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Sample records for plasma deposited heparin-like

  1. Dynamic properties of biologically active synthetic heparin-like hexasaccharides.

    PubMed

    Angulo, Jesús; Hricovíni, Milos; Gairi, Margarida; Guerrini, Marco; de Paz, José Luis; Ojeda, Rafael; Martín-Lomas, Manuel; Nieto, Pedro M

    2005-10-01

    A complete study of the dynamics of two synthetic heparin-like hexasaccharides, D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-1-->iPr (1) and -->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHAc-6-SO4-alpha-(1-->4)-L-IdoA-alpha-(1-->4)-D-GlcNHSO3-alpha-(1-->4)-L-IdoA-2-SO4-alpha-1-->iPr (2), has been performed using 13C-nuclear magnetic resonance (NMR) relaxation parameters, T1, T2, and heteronuclear nuclear Overhauser effect (NOEs). Compound 1 is constituted from sequences corresponding to the major polysaccharide heparin region, while compound 2 contains a sequence never found in natural heparin. They differ from each other only in sulphation patterns, and are capable of stimulating fibroblast growth factors (FGFs)-1 induced mitogenesis. Both oligosaccharides exhibit a remarkable anisotropic overall motion in solution as revealed by their anisotropic ratios (tau /tau||), 4.0 and 3.0 respectively. This is a characteristic behaviour of natural glycosaminoglycans (GAG) which has also been observed for the antithrombin (AT) binding pentasaccharide D-GlcNHSO3-6-SO4-alpha-(1-->4)-D-GlcA-beta-(1-->4)-D-GlcNHSO3-(3,6-SO4)-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-1-->Me (3) (Hricovíni, M., Guerrini, M., Torri, G., Piani, S., and Ungarelli, F. (1995) Conformational analysis of heparin epoxide in aqueous solution. An NMR relaxation study. Carbohydr. Res., 277, 11-23). The motional properties observed for 1 and 2 provide additional support to the suitability of these compounds as heparin models in agreement with previous structural (de Paz, J.L., Angulo, J., Lassaletta, J.M., Nieto, P.M., Redondo-Horcajo, M., Lozano, R.M., Jiménez-Gallego, G., and Martín-Lomas, M. (2001) The activation of fibroblast growth factors by heparin: synthesis, structure and biological activity of heparin-like oligosaccharides. Chembiochem, 2, 673-685; Ojeda, R

  2. Synthesis of heparin-like oligosaccharides on polymer supports.

    PubMed

    Ojeda, Rafael; Terentí, Olimpia; de Paz, José-Luis; Martín-Lomas, Manuel

    2004-01-01

    The biological functions of a variety of proteins are regulated by heparan sulfate glycosaminoglycans. In order to facilitate the elucidation of the molecular basis of glycosaminoglycan-protein interactions we have developed syntheses of heparin-like oligosaccharides on polymer supports. A completely stereoselective strategy previously developed by us for the synthesis of these oligosaccharides in solution has been extended to the solid phase using an acceptor-bound approach. Both a soluble polymer support and a polyethylene glycol-grafted polystyrene resin have been used and different strategies for the attachment of the acceptor to the support have been explored. The attachment of fully protected disaccharide building blocks to a soluble support through the carboxylic group of the uronic acid unit by a succinic ester linkage, the use of trichloroacetimidates as glycosylating agents and of a functionalized Merryfield type resin for the capping process allowed for the construction of hexasaccharide and octasaccharide fragments containing the structural motif of the regular region of heparin. This strategy may facilitate the synthesis of glycosaminoglycan oligosaccharides by using the required building blocks in the glycosylation sequence. PMID:15486451

  3. Plasma Deposition of Amorphous Silicon

    NASA Technical Reports Server (NTRS)

    Calcote, H. F.

    1982-01-01

    Strongly adhering films of silicon are deposited directly on such materials as Pyrex and Vycor (or equivalent materials) and aluminum by a non-equilibrium plasma jet. Amorphous silicon films are formed by decomposition of silicon tetrachloride or trichlorosilane in the plasma. Plasma-jet technique can also be used to deposit an adherent silicon film on aluminum from silane and to dope such films with phosphorus. Ability to deposit silicon films on such readily available, inexpensive substrates could eventually lead to lower cost photovoltaic cells.

  4. Synthesis and structural study of two new heparin-like hexasaccharides.

    PubMed

    Lucas, Ricardo; Angulo, Jesús; Nieto, Pedro M; Martín-Lomas, Manuel

    2003-07-01

    Two new heparin-like hexasaccharides, 5 and 6, have been synthesised using a convergent block strategy and their solution conformations have been determined by NMR spectroscopy and molecular modelling. Both hexasaccharides contain the basic structural motif of the regular region of heparin but with negative charge distributions which have been designed to get insight into the mechanism of fibroblast growth factors (FGFs) activation. PMID:12945695

  5. Conformational changes of fibronectin induced by polystyrene derivatives with a heparin-like function

    SciTech Connect

    Stanislawski, L. ); Serne, H.; Jozefowicz, M. ); Stanislawski, M. )

    1993-05-01

    It was previously reported that polystyrene substituted with the sulfonate group, PSSO[sub 3], which has anticoagulant heparin-like properties, and then coated with fibronectin supports the growth of human umbilical vein endothelial cells. On the other hand, polystyrene substituted with the amino acid sulfamide group, PSSO[sub 2]-Asp, which has a higher anticoagulant activity, and then coated with fibronectin no longer supported the growth of endothelial cells. The authors report here that, while the affinity of fibronectin to either polymer is of the same order of magnitude, fibronectin is adsorbed onto the PSSO[sub 2]-Asp polymer in a different conformation compared to the PSSO[sub 3] polymer. This was shown by a higher binding of polyclonal antifibronectin antibodies to fibronectin-coated PSSO[sub 2]-Asp polymer, and by a decreased susceptibility of the coated fibronectin to proteolysis by thermolysin. This study provides evidence that a solid phase substrate with a strong heparin-like function may influence the conformation and biological properties of fibronectin.

  6. Coating Solar Cells By Microwave Plasma Deposition

    NASA Technical Reports Server (NTRS)

    Minaee, Behrooz; Chitre, Sanjeev R.; Zahedi, Narges

    1991-01-01

    Antireflection films deposited on silicon solar cells at high production rates with microwave-enhanced plasma deposition. Microwave energy at frequency of 2.45 GHz generates plasma in mixture of gases, from which thin film of silicon nitride deposits on silicon substrates. Reaction temperature relatively low (only 250 degrees C), and film deposition rate more than 500 Angstrom/minute - 2 to 5 times faster. Quality of antireflection film similar to that produced by chemical-vapor deposition. Uses less power and consumes smaller quantities of gas. Species formed in plasma longer lived and dissociate reactants in region of chamber well away from plasma-generation region.

  7. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, Peter C.; Watkins, Arthur D.

    1999-01-01

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube.

  8. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, P.C.; Watkins, A.D.

    1999-05-25

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube. 8 figs.

  9. Preparation Of Sources For Plasma Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Waters, William J.; Sliney, Hal; Kowalski, D.

    1993-01-01

    Multicomponent metal targets serving as sources of vapor for plasma vapor deposition made in modified pressureless-sintering process. By use of targets made in modified process, one coats components with materials previously plasma-sprayed or sintered but not plasma-vapor-deposited.

  10. Bio-layer interferometry of a multivalent sulfated virus nanoparticle with heparin-like anticoagulant activity.

    PubMed

    Groner, Myles; Ng, Taryn; Wang, Weidong; Udit, Andrew K

    2015-07-01

    Heparin is a sulfated glycosaminoglycan that is routinely used as an anticoagulant. It is typically purified from bovine or porcine sources, leading to heterogeneity that poses several challenges when used clinically. We have found that the bacteriophage Qβ can be selectively sulfated to yield virus-like nanoparticles (sulf-VLP) that elicit anticoagulant activity similar to heparin. In an effort to explore the binding interactions that heparin-like VLPs make with cationic targets, described herein are bio-layer interferometry studies utilizing the BLItz platform that evaluate the interaction of sulf-VLP with the cationic peptide CDK5 (50% Lys). Streptavidin biosensors modified with biotin-CDK5 were found to bind strongly to sulf-VLP and not to the underivatized nanoparticle. Titration of sulf-VLP yielded concentration-dependent sensorgrams, permitting calculation of rate and equilibrium constants: k(on) = (8 ± 3) × 10(6) s(-1) for the association phase, k(off )= (5 ± 2) × 10(-3) M s(-1) for the dissociation phase, yielding an overall dissociation constant K(D)~ 1 nM. Fitting was best achieved using an equation possessing both exponential and linear terms, suggesting a mechanism more complex than 1:1 binding. To mitigate multivalency and rebinding effects, experiments were conducted with protamine (~70% Arg) added during the dissociation phase, leading to more pronounced dissociation curves and k off values that yielded a near-linear relationship with protamine concentration. PMID:25957844

  11. Angiopoietin-1 prevents severe bleeding complications induced by heparin-like drugs and fibroblast growth factor-2 in mice.

    PubMed

    Jerebtsova, Marina; Das, Jharna R; Tang, Pingtao; Wong, Edward; Ray, Patricio E

    2015-10-01

    Critically ill children can develop bleeding complications when treated with heparin-like drugs. These events are usually attributed to the anticoagulant activity of these drugs. However, previous studies showed that fibroblast growth factor-2 (FGF-2), a heparin-binding growth factor released in the circulation of these patients, could precipitate intestinal hemorrhages in mice treated with the heparin-like drug pentosan polysulfate (PPS). Yet very little is known about how FGF-2 induces bleeding complications in combination with heparin-like drugs. Here, we examined the mechanisms by which circulating FGF-2 induces intestinal hemorrhages in mice treated with PPS. We used a well-characterized mouse model of intestinal hemorrhages induced by FGF-2 plus PPS. Adult FVB/N mice were infected with adenovirus carrying Lac-Z or a secreted form of recombinant human FGF-2, and injected with PPS, at doses that do not induce bleeding complications per se. Mice treated with FGF-2 in combination with PPS developed an intestinal inflammatory reaction that increased the permeability and disrupted the integrity of submucosal intestinal vessels. These changes, together with the anticoagulant activity of PPS, induced lethal hemorrhages. Moreover, a genetically modified form of the endothelial ligand angiopoietin-1 (Ang-1*), which has powerful antipermeability and anti-inflammatory activity, prevented the lethal bleeding complications without correcting the anticoagulant status of these mice. These findings define new mechanisms through which FGF-2 and Ang-1* modulate the outcome of intestinal bleeding complications induced by PPS in mice and may have wider clinical implications for critically ill children treated with heparin-like drugs. PMID:26276817

  12. Plasma Deposition of Doped Amorphous Silicon

    NASA Technical Reports Server (NTRS)

    Calcote, H. F.

    1985-01-01

    Pair of reports present further experimental details of investigation of plasma deposition of films of phosphorous-doped amosphous silicon. Probe measurements of electrical resistance of deposited films indicated films not uniform. In general, it appeared that resistance decreased with film thickness.

  13. Plasma deposited rider rings for hot displacer

    DOEpatents

    Kroebig, Helmut L.

    1976-01-01

    A hot cylinder for a cryogenic refrigerator having two plasma spray deposited rider rings of a corrosion and abrasion resistant material provided in the rider ring grooves, wherein the rider rings are machined to the desired diameter and width after deposition. The rider rings have gas flow flats machined on their outer surface.

  14. On coating adhesion during impulse plasma deposition

    NASA Astrophysics Data System (ADS)

    Nowakowska-Langier, Katarzyna; Zdunek, Krzysztof; Chodun, Rafal; Okrasa, Sebastian; Kwiatkowski, Roch; Malinowski, Karol; Składnik-Sadowska, Elzbieta; Sadowski, Marek J.

    2014-05-01

    The impulse plasma deposition (IPD) technique is the only method of plasma surface engineering (among plasma-based technologies) that allows a synthesis of layers upon a cold unheated substrate and which ensures a good adhesion. This paper presents a study of plasma impacts upon a copper substrate surface during the IPD process. The substrate was exposed to pulsed N2/Al plasma streams during the synthesis of AlN layers. For plasma-material interaction diagnostics, the optical emission spectroscopy method was used. Our results show that interactions of plasma lead to sputtering of the substrate material. It seems that the obtained adhesion of the layers is the result of a complex surface mechanism combined with the effects of pulsed plasma energy impacts upon the unheated substrate. An example of such a result is the value of the critical load for the Al2O3 layer, which was measured by the scratch-test method to be above 40 N.

  15. Monitoring particle growth in deposition plasmas

    NASA Astrophysics Data System (ADS)

    Schlebrowski, T.; Bahre, H.; Böke, M.; Winter, J.

    2013-12-01

    Plasma-enhanced chemical vapor deposition methods are frequently used to deposit barrier layers, e.g. on polymers for food packaging. These plasmas may suffer from particle (dust) formation. We report on a flexible monitoring system for dust. It is based on scanning a 3D plasma volume for particles by laser light scattering. The lower size limit of particles detected in the presented system is 20 nm. We report on existence diagrams for obtaining dust free or dust loaded capacitively or inductively coupled rf-plasmas in C2H2 depending on pressure, flow and rf-power. We further present growth rates for dust in these plasmas and show that monodisperse particles are only obtained during the first growth cycle.

  16. Plasma deposition of aluminum oxide films

    NASA Astrophysics Data System (ADS)

    Catherine, Y.; Talebian, A.

    1988-03-01

    A plasma deposition technique for amorphous aluminum oxide films is discussed. A 450 kHz or 13.56 MHz power supply was used to generate the plasma and the deposition of the film was achieved at low plasma power using trimethyl-aluminum and carbon dioxide reactant sources. It has been found that for the low frequency plasma the growth is strongly dependent upon TMA concentration, indicating that the growth process is mass transport limited. On the other hand using the 13.56 MHz discharge results in a surface controlled growth rate. An increase in the deposition temperature up to 300° C makes the films more dense and lowers their etching rate. FTIR and ESCA measurements showed that oxidation is only completed with high CO2 concentrations and a deposition temperature above 250° C. The dielectric films were found to have a dielectric constant in the range 7.3=2-9 and a refractive index between 1.5 1.8 depending upon deposition conditions.

  17. Plasma deposition of amorphous metal alloys

    DOEpatents

    Hays, A.K.

    1979-07-18

    Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

  18. Plasma deposition of amorphous metal alloys

    DOEpatents

    Hays, Auda K.

    1986-01-01

    Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

  19. Plasma-Modified Atomic Layer Deposition

    NASA Astrophysics Data System (ADS)

    Larrabee, Thomas; Prokes, Sharka

    2015-09-01

    PEALD is known to grow thin films with differing properties from those grown purely via chemical reactions, or thermal ALD processes. However, material properties are still limited when compared to films grown by other deposition techniques. We have used non-growth plasma steps in each ALD cycle to modify properties, in a technique we refer to as plasma-modified ALD. To study how non-growth plasma steps modify properties, we have grown metal oxides with various plasma processing steps from CCPs of Ar, O2, N2, and H2 gases at relatively high pressures of 1-2 mbar. A grid is used to screen ion bombardment of the samples within a commercial Beneq TFS-200 reactor, making this plasma configuration indirect, but not remote. Several properties show significant differences between the films grown with and without these additional steps. These altered properties include crystalline orientation as indicated by XRD, plasmon resonances, photoluminescence, electron paramagnetic resonance, optical dispersion, mobilities, carrier concentrations, and resistivities. Selected plasma-initiated modifications to ALD-grown oxides of zinc, vanadium, and hafnium, and their anticipated applications in novel materials systems will be presented. NRC Postdoc at the Naval Research Laboratory.

  20. Glow discharge plasma deposition of thin films

    DOEpatents

    Weakliem, Herbert A.; Vossen, Jr., John L.

    1984-05-29

    A glow discharge plasma reactor for deposition of thin films from a reactive RF glow discharge is provided with a screen positioned between the walls of the chamber and the cathode to confine the glow discharge region to within the region defined by the screen and the cathode. A substrate for receiving deposition material from a reactive gas is positioned outside the screened region. The screen is electrically connected to the system ground to thereby serve as the anode of the system. The energy of the reactive gas species is reduced as they diffuse through the screen to the substrate. Reactive gas is conducted directly into the glow discharge region through a centrally positioned distribution head to reduce contamination effects otherwise caused by secondary reaction products and impurities deposited on the reactor walls.

  1. Effects of Ar plasma treatment for deposition of ruthenium film by remote plasma atomic layer deposition

    SciTech Connect

    Park, Taeyong; Lee, Jaesang; Park, Jingyu; Jeon, Heeyoung; Jeon, Hyeongtag; Lee, Ki-Hoon; Cho, Byung-Chul; Kim, Moo-Sung; Ahn, Heui-Bok

    2012-01-15

    Ruthenium thin films were deposited on argon plasma-treated SiO{sub 2} and untreated SiO{sub 2} substrates by remote plasma atomic layer deposition using bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp){sub 2}] as a Ru precursor and ammonia plasma as a reactant. The results of in situ Auger electron spectroscopy (AES) analysis indicate that the initial transient region of Ru deposition was decreased by Ar plasma treatment at 400 deg. C, but did not change significantly at 300 deg. C The deposition rate exhibited linearity after continuous film formation and the deposition rates were about 1.7 A/cycle and 0.4 A/cycle at 400 deg. C and 300 deg. C, respectively. Changes of surface energy and polar and dispersive components were measured by the sessile drop test. The quantity of surface amine groups was measured from the surface nitrogen concentration with AES. Furthermore, the Ar plasma-treated SiO{sub 2} contained more amine groups and less hydroxyl groups on the surface than on untreated SiO{sub 2}. Auger spectra exhibited chemical shifts by Ru-O bonding, and larger shifts were observed on untreated substrates due to the strong adhesion of Ru films.

  2. The activation of fibroblast growth factors by heparin: synthesis, structure, and biological activity of heparin-like oligosaccharides.

    PubMed

    de Paz, J L; Angulo, J; Lassaletta, J M; Nieto, P M; Redondo-Horcajo, M; Lozano, R M; Giménez-Gallego, G; Martín-Lomas, M

    2001-09-01

    An effective strategy has been designed for the synthesis of oligosaccharides of different sizes structurally related to the regular region of heparin; this is illustrated by the preparation of hexasaccharide 1 and octasaccharide 2. This synthetic strategy provides the oligosaccharide sequence containing a D-glucosamine unit at the nonreducing end that is not available either by enzymatic or chemical degradation of heparin. It may permit, after slight modifications, the preparation of oligosaccharide fragments with different charge distribution as well. NMR spectroscopy and molecular dynamics simulations have shown that the overall structure of 1 in solution is a stable right-hand helix with four residues per turn. Hexasaccharide 1 and, most likely, octasaccharide 2 are, therefore, chemically well-defined structural models of naturally occurring heparin-like oligosaccharides for use in binding and biological activity studies. Both compounds 1 and 2 induce the mitogenic activity of acid fibroblast growth factor (FGF1), with the half-maximum activating concentration of 2 being equivalent to that of heparin. Sedimentation equilibrium analysis with compound 2 suggests that heparin-induced FGF1 dimerization is not an absolute requirement for biological activity. PMID:11828504

  3. Basic fibroblast growth factor binds to subendothelial extracellular matrix and is released by heparitinase and heparin-like molecules

    SciTech Connect

    Bashkin, P.; Doctrow, S.; Klagsbrun, M.; Svahn, C.M.; Folkman, J.; Vlodavsky, I. )

    1989-02-21

    Basic fibroblast growth factor (bFGF) exhibits specific binding to the extracellular matrix (ECM) produced by cultured endothelial cells. Binding was saturable as a function both of time and of concentration of {sup 125}I-bFGF. Scatchard analysis of FGF binding revealed the presence of about 1.5 x 10{sup 12} binding sites/mm{sup 2} ECM with an apparent k{sub D} of 610 nM. FGF binds to heparan sulfate (HS) in ECM as evidenced by (i) inhibition of binding in the presence of heparin or HS at 0.1-1 {mu}g/mL, but not by chondroitin sulfate, keratan sulfate, or hyaluronic acid at 10 {mu}g/mL, (ii) lack of binding to ECM pretreated with heparitinase, but not with chondroitinase ABC, and (iii) rapid release of up to 90% of ECM-bound FGF by exposure to heparin, HS, or heparitinase, but not to chondroitin sulfate, keratan sulfate, hyaluronic acid, or chondroitinase ABC. Oligosaccharides derived from depolymerized heparin, and as small as the tetrasaccharide, released the ECM-bound FGF, but there was little or no release of FGF by modified nonanticoagulant heparins such as totally desulfated heparin, N-desulfated heparin, and N-acetylated heparin. FGF released from ECM was biologically active, as indicated by its stimulation of cell proliferation and DNA synthesis in vascular endothelial cells and 3T3 fibroblasts. Similar results were obtained in studies on release of endogenous FGF-like mitogenic activity from Descement's membranes of bovine corneas. It is suggested that ECM storage and release of bFGF provide a novel mechanism for regulation of capillary blood vessel growth. Whereas ECM-bound FGF may be prevented from acting on endothelial cells, its displacement by heparin-like molecules and/or HS-degrading enzymes may elicit a neovascular response.

  4. Deposition of diamond-like films by ECR microwave plasma

    NASA Technical Reports Server (NTRS)

    Shing, Yuh-Han (Inventor); Pool, Frederick S. (Inventor)

    1995-01-01

    Hard amorphous hydrogenated carbon, diamond-like films are deposited using an electron cyclotron resonance microwave plasma with a separate radio frequency power bias applied to a substrate stage. The electron cyclotron resonance microwave plasma yields low deposition pressure and creates ion species otherwise unavailable. A magnetic mirror configuration extracts special ion species from a plasma chamber. Different levels of the radio frequency power bias accelerate the ion species of the ECR plasma impinging on a substrate to form different diamond-like films. During the deposition process, a sample stage is maintained at an ambient temperature of less than 100.degree. C. No external heating is applied to the sample stage. The deposition process enables diamond-like films to be deposited on heat-sensitive substrates.

  5. Plasma sprayed and electrospark deposited zirconium metal diffusion barrier coatings

    SciTech Connect

    Hollis, Kendall J; Pena, Maria I

    2010-01-01

    Zirconium metal coatings applied by plasma spraying and electrospark deposition (ESD) have been investigated for use as diffusion barrier coatings on low enrichment uranium fuel for research nuclear reactors. The coatings have been applied to both stainless steel as a surrogate and to simulated nuclear fuel uranium-molybdenum alloy substrates. Deposition parameter development accompanied by coating characterization has been performed. The structure of the plasma sprayed coating was shown to vary with transferred arc current during deposition. The structure of ESD coatings was shown to vary with the capacitance of the deposition equipment.

  6. Plasma assisted deposition of metal fluorides for 193nm applications

    NASA Astrophysics Data System (ADS)

    Bischoff, Martin; Sode, Maik; Gaebler, Dieter; Kaiser, Norbert; Tuennermann, Andreas

    2008-10-01

    The ArF lithography technology requires a minimization of optical losses due to scattering and absorption. Consequently it is necessary to optimize the coating process of metal fluorides. The properties of metal fluoride thin films are mainly affected by the deposition methods, their parameters, and the vacuum conditions. Until now the best results were achieved by metal boat evaporation with high substrate temperature and without plasma assistance. In fact, it was demonstrated that the plasma assisted deposition process results in optical thin films with high packing density but the losses due to absorption were extremely high for deep and vacuum ultraviolet applications. This paper will demonstrate that most of the common metal fluorides can be deposited by electron beam evaporation with plasma assistance. In comparison to other deposition methods, the prepared thin films show low absorption in the VUV spectral range, high packing density, and less water content. The densification of the thin films was performed by a Leybold LION plasma source. As working gas, a variable mixture of fluorine and argon gas was chosen. To understand the deposition process and the interaction of the plasma with the deposition material, various characterization methods like plasma emission spectroscopy and ion current measurements were implemented.

  7. Vapor Phase Deposition Using Plasma Spray-PVD™

    NASA Astrophysics Data System (ADS)

    von Niessen, K.; Gindrat, M.; Refke, A.

    2010-01-01

    Plasma spray—physical vapor deposition (PS-PVD) is a low pressure plasma spray technology to deposit coatings out of the vapor phase. PS-PVD is a part of the family of new hybrid processes recently developed by Sulzer Metco AG (Switzerland) on the basis of the well-established low pressure plasma spraying (LPPS) technology. Included in this new process family are plasma spray—chemical vapor deposition (PS-CVD) and plasma spray—thin film (PS-TF) processes. In comparison to conventional vacuum plasma spraying and LPPS, these new processes use a high energy plasma gun operated at a work pressure below 2 mbar. This leads to unconventional plasma jet characteristics which can be used to obtain specific and unique coatings. An important new feature of PS-PVD is the possibility to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats, but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional PVD technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and EB-PVD coatings. This paper reports on the progress made at Sulzer Metco to develop functional coatings build up from vapor phase of oxide ceramics and metals.

  8. Metal plasma immersion ion implantation and deposition: A review

    SciTech Connect

    Anders, A.

    1996-09-01

    Metal Plasma Immersion Ion Implantation and Deposition (MePIIID) is a hybrid process combining cathodic arc deposition and plasma immersion ion implantation. The properties of metal plasma produced by vacuum arcs are reviewed and the consequences for MePIIID are discussed. Different version of MePIIID are described and compared with traditional methods of surface modification such as ion beam assisted deposition (IBAD). MePIIID is a very versatile approach because of the wide range of ion species and energies used. In one extreme case, films are deposited with ions in the energy range 20--50 eV, and at the other extreme, ions can be implanted with high energy (100 keV or more) without film deposition. Novel features of the technique include the use of improved macroparticle filters; the implementation of several plasma sources for multi-element surface modification; tuning of ion energy during implantation and deposition to tailor the substrate-film intermixed layer and structure of the growing film; simultaneous pulsing of the plasma potential (positive) and substrate bias (negative) with a modified Marx generator; and the use of high ion charge states.

  9. Ion deposition by inductively coupled plasma mass spectrometry

    SciTech Connect

    Hu, K.; Houk, R.S.

    1996-03-01

    An atmospheric pressure inductively coupled plasma (ICP) is used with a quadrupole mass spectrometer (MS) for ion deposition. The deposited element is introduced as a nebulized aqueous solution. Modifications to the ICP-MS device allow generation and deposition of a mass-resolved beam of {sup 165}Ho{sup +} at 5{times}10{sup 12} ions s{sup {minus}1}. The ICP is a universal, multielement ion source that can potentially be used for applications such as deposition of mixtures of widely varying stoichiometry or of alternating layers of different elements. {copyright} {ital 1996 American Vacuum Society}

  10. Plasma sputtering system for deposition of thin film combinatorial libraries

    NASA Astrophysics Data System (ADS)

    Cooper, James S.; Zhang, Guanghai; McGinn, Paul J.

    2005-06-01

    The design of a plasma sputtering system for the deposition of combinatorial libraries is described. A rotating carousel is used to position shadow masks between the targets and the substrate. Multilayer films are built up by depositing sequentially through various masks. Postdeposition annealing is used to promote interdiffusion of the layered structures. Either discrete or compositional gradient libraries can be deposited in this system. Samples appropriate for characterization with a scanning electrochemical microscope or a multichannel microelectrode array system can be produced. The properties of some deposited Pt-Ru films for fuel cell applications are described.

  11. Film synthesis on powders by cathodic arc plasma deposition

    SciTech Connect

    Anders, A.; Anders, S.; Brown, I.G.; Ivanov, I.C.

    1995-04-01

    Cathodic arc plasma deposition was used to coat Al{sub 2}O{sub 3} powder (mesh size 60) with platinum. The power particles were moved during deposition using a mechanical system operating at a resonance frequency of 20 Hz. Scanning electron microscopy and Auger electron microscopy show that all particles are completely coated with a platinum film having a thickness of about 100 nm. The actual deposition time was only 20 s, thus the deposition rate was very high (5 nm/s).

  12. Modeling of Oxidation of Molybdenum Particles during Plasma Spray Deposition

    SciTech Connect

    Fincke, James Russell; Wan, Y. P.; Jiang, X. Y.; Sampath, S.; Prasad, V.; Herman, H.

    2001-06-01

    An oxidation model for molybdenum particles during the plasma spray deposition process is presented. Based on a well-verified model for plasma chemistry and the heating and phase change of particles in a plasma plume, this model accounts for the oxidant diffusion around the surface of particles or splats, oxidation on the surface, as well as oxygen diffusion in molten molybdenum. Calculations are performed for a single molybdenum particle sprayed under Metco-9MB spraying conditions. The oxidation features of particles during the flight are compared with those during the deposition. The result shows the dominance of oxidation of a molybdenum particle during the flight, as well as during deposition when the substrate temperature is high (above 400 °C).

  13. Laser/Plasma/Chemical-Vapor Deposition Of Diamond

    NASA Technical Reports Server (NTRS)

    Hsu, George C.

    1989-01-01

    Proposed process for deposition of diamond films includes combination of plasma induced in hydrocarbon feed gas by microwave radiation and irradiation of plasma and substrate by lasers. Deposition of graphite suppressed. Reaction chamber irradiated at wavelength favoring polymerization of CH2 radical into powders filtered out of gas. CH3 radicals, having desired sp3 configuration, remains in gas to serve as precursors for deposition. Feed gas selected to favor formation of CH3 radicals; candidates include CH4, C2H4, C2H2, and C2H6. Plasma produced by applying sufficient power at frequency of 2.45 GHz and adjusting density of gas to obtain electron kinetic energies around 100 eV in low-pressure, low-temperature regime.

  14. Modeling of formation of deposited layer by plasma spray process

    NASA Astrophysics Data System (ADS)

    Lee, Joo-Dong; Ra, Hyung-Yong; Hong, Kyung-Tae; Hur, Sung-Kang

    1992-03-01

    An analytical model is developed to describe the plasma deposition process in which average solidified thickness and coating and substrate temperatures are obtained. During the deposition process, the solidification rate is periodically varied, due to the impingement of liquid splats, and the amount of liquid in the coating layer increases. Periodical variation of the solidification rate causes temperature fluctuation in coating and substrate. The nature of interfacial structure of plasma-sprayed NiCrBSi MA powder is compared with the result predicted using the model, which indicates that the liquid deposited at the coating surface during deposition causes discontinuous boundaries within the coating. The spraying rate and the solidification rate reverse periodically with spraying process.

  15. Plasma deposited silicon nitride for indium phosphide encapsulation

    NASA Technical Reports Server (NTRS)

    Valco, G. J.; Kapoor, V. J.; Biedenbender, M. D.; Williams, W. D.

    1989-01-01

    The composition and the annealing characteristics of plasma-deposited silicon-nitride encapsulating films on the ion-implanted InP substrates were investigated, using two different substrate-cleaning procedures (organic solvents and HF or HIO3 solutions) prior to encapsulation. The effect of plasma deposition of silicon nitride on the InP substrates was assessed through the current-voltage characteristics of Schottky diodes. Results of XPS analyses showed that the cleaning procedure that employed HF solution left less oxygen on the InP surface than the procedure involving HIO3. No chemical interaction between the film and the substrate was observed before or after annealing.

  16. Thermal properties of plasma-sprayed tungsten deposits

    NASA Astrophysics Data System (ADS)

    Kang, Hyun-Ki

    2004-10-01

    Tungsten powder was plasma-sprayed onto a graphite substrate in order to examine the microstructures, porosities, and thermal conductivities of tungsten deposits. Tungsten was partially oxidized to tungsten oxide (WO 3) after plasma spraying. Most pores were found in the vicinity of lamellar layers in association with oxidation. It was revealed that both tungsten oxide and the lamellar structure with pores have a significant influence on the electrical and thermal conductivity.

  17. Human recombinant interleukin-1 beta- and tumor necrosis factor alpha-mediated suppression of heparin-like compounds on cultured porcine aortic endothelial cells

    SciTech Connect

    Kobayashi, M.; Shimada, K.; Ozawa, T. )

    1990-09-01

    Cytokines are known to tip the balance of the coagulant-anticoagulant molecules on the endothelial cell surface toward intravascular coagulation. Their effects on endothelial cell surface-associated heparin-like compounds have not been examined yet. Incorporation of (35S)sulfate into heparan sulfate on cultured porcine aortic endothelial cells was suppressed by human recombinant interleukin-1 beta (rIL-1 beta) or tumor necrosis factor alpha (rTNF alpha) in a dose- and time-dependent manner with little effect on cell number, protein content, and (3H)leucine incorporation of cells. Maximal inhibition was achieved by incubation of cells with 100 ng/ml of rIL-1 beta or 5 ng/ml of rTNF alpha for 12-24 hours, resulting in a reduction of the synthesis of heparan sulfate on the cell surface by approximately 50%. The dose dependency was consistent with that seen in the stimulation of endothelial cell procoagulant activity by each cytokine. The suppression of heparan sulfate synthesis was sustained for at least 48 hours after pretreatment of cells with cytokines and was unchanged after the addition of indomethacin or polymyxin B. The rate of degradation of prelabeled 35S-heparan sulfate on the cell surface was not altered by cytokine treatments. Neither the size, the net negative charge, nor the proportion of the molecule with high affinity for antithrombin III of endothelial cell heparan sulfate was changed by cytokines. Furthermore, specific binding of 125I-labeled antithrombin III to the endothelial cell surface was reduced to 40-60% of control by cytokines. In parallel with reduction in binding, antithrombin III cofactor activity was partially diminished in cytokine-treated endothelial cells. Thus, cytokine-mediated suppression of heparin-like substance on endothelial cells appears to be another cytokine-inducible endothelial effects affecting coagulation.

  18. Modeling of Erosion and Deposition on Plasma Facing Walls

    SciTech Connect

    Ohya, K.

    2010-05-20

    The unavoidable contact of plasmas with surrounding walls results in plasma-surface interactions (PSIs) that are strongly interlinked and cannot be studied separately. Computer modeling has become increasingly important in understanding mechanisms of PSIs in present devices, ITER and beyond. Modeling of erosion and deposition requires self-consistent calculations of (1) erosion of the wall surface, (2) transport of eroded impurities in the plasma above the surface, (3) redeposition of returning impurities on the surface and (4) resultant material mixing below the surface. In addition, it is necessary to use exact rate coefficients for collision reactions in the plasma and related data for the surface reactions on plasma-facing walls. This chapter describes modeling codes in terms of such PSI issues and the physical and chemical bases of the interactions.

  19. Modeling and Simulation of Plasma Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Smith, Aaron; Bett, Dominic; Cunningham, Monisha; Sen, Sudip

    2015-04-01

    Plasma Enhanced Chemical Vapor Deposition (PECVD) is a process used to deposit thin films from a gas state (vapor) to a solid state on a substrate. Recent study from the X-ray diffraction spectra of SnO2 films deposited as a function of RF power apparently indicates that RF power is playing a stabilizing role and hence in the better deposition. The results show that the RF power results in smoother morphology, improved crystallinity, and lower sheet resistance value in the PECVD process. The PECVD processing allows deposition at lower temperatures, which is often critical in the manufacture of semiconductors. In this talk we will address two aspects of the problem, first to develop a model to study the mechanism of how the PECVD is effected by the RF power, and second to actually simulate the effect of RF power on PECVD. As the PECVD is a very important component of the plasma processing technology with many applications in the semiconductor technology and surface science, the research proposed here has the prospect to revolutionize the plasma processing technology through the stabilizing role of the RF power.

  20. Carbon deposition on metallic surfaces studied by RF plasma discharge

    NASA Astrophysics Data System (ADS)

    Cairns, J. A.; Coad, J. P.; Richards, E. W. T.; Stenhouse, I. A.

    1980-12-01

    The accumulation of carbonaceous deposits on surfaces exposed to gases containing hydrocarbons or carbon monoxide, such as the stainless steel fuel pins in an advanced gas-cooled nuclear reactor, is investigated by means of an RF plasma discharge system. Specimens of the 20/25/Nb steel used for the fuel pins and of copper were subjected to an RF plasma discharge of a CO/CH4 gas mixture, and the amounts and compositions of the deposits formed were determined. The steel is observed to acquire a significant deposit of carbon after 4 h in the discharge, while the copper remained essentially clean. When the steel is coated with a silica layer, however, it is also found to remain clean throughout its exposure, while nearby uncoated steel specimens were contaminated. Spectroscopic examination of the light emitted from the plasma in the vicinity of the specimens indicates that the carbonaceous deposition is induced largely by the catalytic activity of the steel surface itself, and that deposition can be prevented by the use of suitable coatings.

  1. Plasma deposition of polymer composite films incorporating nanocellulose whiskers

    NASA Astrophysics Data System (ADS)

    Samyn, P.; Airoudj, A.; Laborie, M.-P.; Mathew, A. P.; Roucoules, V.

    2011-11-01

    In a trend for sustainable engineering and functionalization of surfaces, we explore the possibilities of gas phase processes to deposit nanocomposite films. From an analysis of pulsed plasma polymerization of maleic anhydride in the presence of nanocellulose whiskers, it seems that thin nanocomposite films can be deposited with various patterns. By specifically modifying plasma parameters such as total power, duty cycle, and monomer gas pressure, the nanocellulose whiskers are either incorporated into a buckled polymer film or single nanocellulose whiskers are deposited on top of a polymeric film. The density of the latter can be controlled by modifying the exact positioning of the substrate in the reactor. The resulting morphologies are evaluated by optical microscopy, AFM, contact angle measurements and ellipsometry.

  2. Plasma deposited diamond-like carbon films for large neutralarrays

    SciTech Connect

    Brown, I.G.; Blakely, E.A.; Bjornstad, K.A.; Galvin, J.E.; Monteiro, O.R.; Sangyuenyongpipat, S.

    2004-07-15

    To understand how large systems of neurons communicate, we need to develop methods for growing patterned networks of large numbers of neurons. We have found that diamond-like carbon thin films formed by energetic deposition from a filtered vacuum arc carbon plasma can serve as ''neuron friendly'' substrates for the growth of large neural arrays. Lithographic masks can be used to form patterns of diamond-like carbon, and regions of selective neuronal attachment can form patterned neural arrays. In the work described here, we used glass microscope slides as substrates on which diamond-like carbon was deposited. PC-12 rat neurons were then cultured on the treated substrates and cell growth monitored. Neuron growth showed excellent contrast, with prolific growth on the treated surfaces and very low growth on the untreated surfaces. Here we describe the vacuum arc plasma deposition technique employed, and summarize results demonstrating that the approach can be used to form large patterns of neurons.

  3. Plasma and Ion Assistance in Physical Vapor Deposition: AHistorical Perspective

    SciTech Connect

    Anders, Andre

    2007-02-28

    Deposition of films using plasma or plasma-assist can betraced back surprisingly far, namely to the 18th century for arcs and tothe 19th century for sputtering. However, only since the 1960s thecoatings community considered other processes than evaporation for largescale commercial use. Ion Plating was perhaps the first importantprocess, introducing vapor ionization and substrate bias to generate abeam of ions arriving on the surface of the growing film. Ratherindependently, cathodic arc deposition was established as an energeticcondensation process, first in the former Soviet Union in the 1970s, andin the 1980s in the Western Hemisphere. About a dozen various ion-basedcoating technologies evolved in the last decades, all characterized byspecific plasma or ion generation processes. Gridded and gridless ionsources were taken from space propulsion and applied to thin filmdeposition. Modeling and simulation have helped to make plasma and ionseffects to be reasonably well understood. Yet--due to the complex, oftennon-linear and non-equilibrium nature of plasma and surfaceinteractions--there is still a place for the experience plasma"sourcerer."

  4. Enhanced surface functionality via plasma modification and plasma deposition techniques to create more biologically relevant materials

    NASA Astrophysics Data System (ADS)

    Shearer, Jeffrey C.

    Functionalizing nanoparticles and other unusually shaped substrates to create more biologically relevant materials has become central to a wide range of research programs. One of the primary challenges in this field is creating highly functionalized surfaces without modifying the underlying bulk material. Traditional wet chemistry techniques utilize thin film depositions to functionalize nanomaterials with oxygen and nitrogen containing functional groups, such as --OH and --NHx. These functional groups can serve to create surfaces that are amenable to cell adhesion or can act as reactive groups for further attachment of larger structures, such as macromolecules or antiviral agents. Additional layers, such as SiO2, are often added between the nanomaterial and the functionalized coating to act as a barrier films, adhesion layers, and to increase overall hydrophilicity. However, some wet chemistry techniques can damage the bulk material during processing. This dissertation examines the use of plasma processing as an alternative method for producing these highly functionalized surfaces on nanoparticles and polymeric scaffolds through the use of plasma modification and plasma enhanced chemical vapor deposition techniques. Specifically, this dissertation will focus on (1) plasma deposition of SiO2 barrier films on nanoparticle substrates; (2) surface functionalization of amine and alcohol groups through (a) plasma co-polymerization and (b) plasma modification; and (3) the design and construction of plasma hardware to facilitate plasma processing of nanoparticles and polymeric scaffolds. The body of work presented herein first examines the fabrication of composite nanoparticles by plasma processing. SiOxC y and hexylamine films were coated onto TiO2 nanoparticles to demonstrate enhanced water dispersion properties. Continuous wave and pulsed allyl alcohol plasmas were used to produce highly functionalized Fe2 O3 supported nanoparticles. Specifically, film composition was

  5. Computer Simulation of Plasma Immersion Ion Implantation and Deposition

    NASA Astrophysics Data System (ADS)

    Miyagawa, Yoshiko; Tanaka, Masaaki; Nakadate, Hiroshi; Nakao, Setsuo; Miyagawa, Soji

    By using a newly developed simulation program "PEGASUS", plasma behavior was analyzed for the plasma immersion ion implantation and deposition (PIII&D). For plasma analysis of low pressure gas which is used in PIII&D, the software uses a particle in cell (PIC) method for the analysis of electric and magnetic fields and the motion of charged particles. A Monte Carlo collision method is used for collisions of ions, electrons and neutrals in the plasma, and the dynamic-SASAMAL code is used for the ion-solid surface interactions. Spatial distributions of potential, electron density and ion density together with the ion flux distribution on the target surface were calculated for the case where a negative pulse voltage was applied to a trench shaped target immersed in a high density Ar plasma (1010 cm-3). The time evolution of sheath length obtained by the simulations for a flat plane part of the surface agreed with the analytical result obtained by the Child-Langmuir method. In a bipolar pulse PIII&D system, a positive and a negative pulse voltages are applied alternately to a workpiece without any other external plasma source. Simulation has been conducted for a target immersed in a very low density Ar plasma (107 cm-3) to compare the plasma generated by a negative and a positive pulse voltage applied to the target. When a negative pulse voltage is applied to the target, only a weak plasma is generated. In contrast to it, when a positive pulse voltage is applied, a two-order or more high density plasma is generated under the same condition. The plasma behavior around a trench shaped target is also presented.

  6. Caracterisation of Titanium Nitride Layers Deposited by Reactive Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Roşu, Radu Alexandru; Şerban, Viorel-Aurel; Bucur, Alexandra Ioana; Popescu, Mihaela; Uţu, Dragoş

    2011-01-01

    Forming and cutting tools are subjected to the intense wear solicitations. Usually, they are either subject to superficial heat treatments or are covered with various materials with high mechanical properties. In recent years, thermal spraying is used increasingly in engineering area because of the large range of materials that can be used for the coatings. Titanium nitride is a ceramic material with high hardness which is used to cover the cutting tools increasing their lifetime. The paper presents the results obtained after deposition of titanium nitride layers by reactive plasma spraying (RPS). As deposition material was used titanium powder and as substratum was used titanium alloy (Ti6Al4V). Macroscopic and microscopic (scanning electron microscopy) images of the deposited layers and the X ray diffraction of the coatings are presented. Demonstration program with layers deposited with thickness between 68,5 and 81,4 μm has been achieved and presented.

  7. Deposition of diamondlike films by electron cyclotron resonance microwave plasmas

    NASA Technical Reports Server (NTRS)

    Pool, F. S.; Shing, Y. H.

    1990-01-01

    Hard a-C:H films have been deposited through electron cyclotron resonance (ECR) microwave plasma decomposition of CH4 diluted with H2 gas. It has been found that hard diamondlike films could only be produced under a RF-induced negative self-bias of the substrate stage. Raman spectra indicate the deposition of two distinct film types: one film type exhibiting well-defined bands at 1360 and 1580/cm and another displaying a broad Raman peak centered at approximately 1500/cm. Variation of the mirror magnetic-field profile of the ECR system was examined, demonstrating the manipulation of film morphology through the extraction of different ion energies.

  8. Synthesis and Deposition of Nanoparticles Using a Hypersonically Expanded Plasma

    SciTech Connect

    Hafiz, Jami; Wang Xiaoliang; Mukherjee, Rajesh; McMurry, Peter H.; Heberlein, Joachim V.R.; Girshick, Steven L.

    2005-10-31

    Si-Ti-N nanostructured coatings were synthesized by inertial impaction of nanoparticles using a process called hypersonic plasma particle deposition (HPPD). Transmission electron microscopy on samples prepared by focused ion beam (FIB) milling show TiN nanocrystallites in an amorphous matrix. X-ray photoelectron spectroscopy results indicate the presence of amorphous Si3N4 in similar films. In-situ particle size distribution measurements show that particle size distributions peak around 14 nm under typical operating conditions.

  9. Deposition Of Diamondlike Films By ECR Microwave Plasma

    NASA Technical Reports Server (NTRS)

    Pool, Frederick S.; Shing, Yuh-Han

    1991-01-01

    Hard, amorphous hydrogenated carbon films of diamondlike quality deposited at room temperature on silicon, optical glass, and quartz through decomposition of CH4 in electron-cyclotron-resonance (ECR) microwave plasma of CH4 diluted with H2. Technique provides hard, abrasion-resistant coatings for lenses and other optical components. Films chemically inert and posses high electrical resistivity and breakdown fields, valuable properties in microelectronics applications.

  10. Plasma deposition and surface modification techniques for wear resistance

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1982-01-01

    The ion-assisted or plasma coating technology is discussed as it applies to the deposition of hard, wear resistant refractory compound films. Of the many sputtering and ion plating modes and configurations the reactive magnetron sputtering and the reactive triode ion plating techniques are the preferred ones to deposit wear resistant coatings for tribological applications. Both of these techniques incorporate additional means to enhance the ionization efficiency and chemical reaction to precision tailor desirable tribological characteristics. Interrelationships between film formation, structure, and ribological properties are strictly controlled by the deposition parameters and the substrate condition. The enhanced ionization contributes to the excellent adherence and coherence, reduced internal stresses and improved structural growth to form dense, cohesive, equiaxed grain structure for improved wear resistance and control.

  11. Plasma enhanced atomic layer deposition of ultrathin oxides on graphene

    NASA Astrophysics Data System (ADS)

    Trimble, Christie J.; Zaniewski, Anna M.; Kaur, Manpuneet; Nemanich, Robert J.

    2015-03-01

    Graphene, a single atomic layer of sp2 bonded carbon atoms, possesses extreme material properties that point toward a plethora of potential electronic applications. Many of these possibilities require the combination of graphene with dielectric materials such as metal oxides. Simultaneously, there is interest in new physical properties that emerge when traditionally three dimensional materials are constrained to ultrathin layers. For both of these objectives, we explore deposition of ultrathin oxide layers on graphene. In this project, we perform plasma enhanced atomic layer deposition (PEALD) of aluminum oxide on graphene that has been grown by chemical vapor deposition atop copper foil and achieve oxide layers that are <1.5 nm. Because exposure to oxygen plasma can cause the graphene to deteriorate, we explore techniques to mitigate this effect and optimize the PEALD process. Following deposition, the graphene and oxide films are transferred to arbitrary substrates for further analysis. We use x-ray photoelectron spectroscopy, Raman spectroscopy, and atomic force microscopy to assess the quality of the resulting films. This work is supported by the National Science Foundation under Grant # DMR-1206935.

  12. Plasma deposition of antimicrobial coating on organic polymer

    NASA Astrophysics Data System (ADS)

    Rżanek-Boroch, Zenobia; Dziadczyk, Paulina; Czajkowska, Danuta; Krawczyk, Krzysztof; Fabianowski, Wojciech

    2013-02-01

    Organic materials used for packing food products prevent the access of microorganisms or gases, like oxygen or water vapor. To prolong the stability of products, preservatives such as sulfur dioxide, sulfites, benzoates, nitrites and many other chemical compounds are used. To eliminate or limit the amount of preservatives added to food, so-called active packaging is sought for, which would limit the development of microorganisms. Such packaging can be achieved, among others, by plasma modification of a material to deposit on its surface substances inhibiting the growth of bacteria. In this work plasma modification was carried out in barrier discharge under atmospheric pressure. Sulfur dioxide or/and sodium oxide were used as the coating precursors. As a result of bacteriological studies it was found that sulfur containing coatings show a 16% inhibition of Salmonella bacteria growth and 8% inhibition of Staphylococcus aureus bacteria growth. Sodium containing coatings show worse (by 10%) inhibiting properties. Moreover, films with plasma deposited coatings show good sealing properties against water vapor. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  13. Hardness of CNx films deposited by MCECR plasma sputtering

    NASA Astrophysics Data System (ADS)

    Cai, Changlong; Li, Junpeng; Mi, Qian; Ma, Weihong; Yan, Yixin; Liang, Haifeng

    2007-12-01

    The CNx (carbon nitride) films were deposited on silicon (100) with Mirror-Confinement-type Electron Cyclotron Resonance (MCECR) plasma sputtering method, which sputters pure carbon target with the Ar/N II plasma. The thickness of CNx films was about 80nm. In this paper, the hardness of CNx films was investigated, and it is measured by the nanoindenter. The technical parameters of MCECR plasma sputtering influencing the hardness of CNx films include the substrate bias, microwave power, target voltage, gas pressure, and the Ar/N II ratio. Results shown that, the hardness of CNx films is bigger, when the substrate bias is at +30V, the microwave power is 200W, the target voltage is +500V, the gas pressure is 2×10 -2Pa, and the Ar/N II ratio is 9/1.

  14. Stress control of silicon nitride films deposited by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Li, Dong-ling; Feng, Xiao-fei; Wen, Zhi-yu; Shang, Zheng-guo; She, Yin

    2016-07-01

    Stress controllable silicon nitride (SiNx) films deposited by plasma enhanced chemical vapor deposition (PECVD) are reported. Low stress SiNx films were deposited in both high frequency (HF) mode and dual frequency (HF/LF) mode. By optimizing process parameters, stress free (-0.27 MPa) SiNx films were obtained with the deposition rate of 45.5 nm/min and the refractive index of 2.06. Furthermore, at HF/LF mode, the stress is significantly influenced by LF ratio and LF power, and can be controlled to be 10 MPa with the LF ratio of 17% and LF power of 150 W. However, LF power has a little effect on the deposition rate due to the interaction between HF power and LF power. The deposited SiNx films have good mechanical and optical properties, low deposition temperature and controllable stress, and can be widely used in integrated circuit (IC), micro-electro-mechanical systems (MEMS) and bio-MEMS.

  15. Positron deposition in plasmas by positronium beam ionization and transport of positrons in tokamak plasmas

    SciTech Connect

    Murphy, T.J.

    1986-11-01

    In a recently proposed positron transport experiment, positrons would be deposited in a fusion plasma by forming a positronium (Ps) beam and passing it through the plasma. Positrons would be deposited as the beam is ionized by plasma ions and electrons. Radial transport of the positrons to the limiter could then be measured by detecting the gamma radiation produced by annihilation of positrons with electrons in the limiter. This would allow measurements of the transport of electron-mass particles and might shed some light on the mechanisms of electron transport in fusion plasmas. In this paper, the deposition and transport of positrons in a tokamak are simulated and the annihilation signal determined for several transport models. Calculations of the expected signals are necessary for the optimal design of a positron transport experiment. There are several mechanisms for the loss of positrons besides transport to the limiter. Annihilation with plasma electrons and reformation of positronium in positron-hydrogen collisions are two such processes. These processes can alter the signal and place restrictions ons on the plasma conditions in which positron transport experiments can be effectively performed.

  16. Diagnostic for Plasma Enhanced Chemical Vapor Deposition and Etch Systems

    NASA Technical Reports Server (NTRS)

    Cappelli, Mark A.

    1999-01-01

    In order to meet NASA's requirements for the rapid development and validation of future generation electronic devices as well as associated materials and processes, enabling technologies ion the processing of semiconductor materials arising from understanding etch chemistries are being developed through a research collaboration between Stanford University and NASA-Ames Research Center, Although a great deal of laboratory-scale research has been performed on many of materials processing plasmas, little is known about the gas-phase and surface chemical reactions that are critical in many etch and deposition processes, and how these reactions are influenced by the variation in operating conditions. In addition, many plasma-based processes suffer from stability and reliability problems leading to a compromise in performance and a potentially increased cost for the semiconductor manufacturing industry. Such a lack of understanding has hindered the development of process models that can aid in the scaling and improvement of plasma etch and deposition systems. The research described involves the study of plasmas used in semiconductor processes. An inductively coupled plasma (ICP) source in place of the standard upper electrode assembly of the Gaseous Electronics Conference (GEC) radio-frequency (RF) Reference Cell is used to investigate the discharge characteristics and chemistries. This ICP source generates plasmas with higher electron densities (approximately 10(exp 12)/cu cm) and lower operating pressures (approximately 7 mTorr) than obtainable with the original parallel-plate version of the GEC Cell. This expanded operating regime is more relevant to new generations of industrial plasma systems being used by the microelectronics industry. The motivation for this study is to develop an understanding of the physical phenomena involved in plasma processing and to measure much needed fundamental parameters, such as gas-phase and surface reaction rates. species

  17. Radio-frequency plasma chemical vapor deposition growth of diamond

    NASA Technical Reports Server (NTRS)

    Meyer, Duane E.; Dillon, Rodney O.; Woollam, John A.

    1989-01-01

    Plasma chemical vapor deposition (CVD) at 13.56 MHz has been used to produce diamond particles in two different inductively coupled systems with a mixture of methane and hydrogen. The effect of a diamondlike carbon (DLC) overcoating on silicon, niobium, and stainless-steel substrates has been investigated and in the case of silicon has been found to enhance particle formation as compared to uncoated polished silicon. In addition the use of carbon monoxide in hydrogen has been found to produce well-defined individual faceted particles as well as polycrystalline films on quartz and DLC coated silicon substrates. Plasma CVD is a competitive approach to production of diamond films. It has the advantage over microwave systems of being easily scaled to large volume and high power.

  18. Plasma-enhanced chemical vapor deposition of multiwalled carbon nanofibers

    NASA Technical Reports Server (NTRS)

    Matthews, Kristopher; Cruden, Brett A.; Chen, Bin; Meyyappan, M.; Delzeit, Lance

    2002-01-01

    Plasma-enhanced chemical vapor deposition is used to grow vertically aligned multiwalled carbon nanofibers (MWNFs). The graphite basal planes in these nanofibers are not parallel as in nanotubes; instead they exhibit a small angle resembling a stacked cone arrangement. A parametric study with varying process parameters such as growth temperature, feedstock composition, and substrate power has been conducted, and these parameters are found to influence the growth rate, diameter, and morphology. The well-aligned MWNFs are suitable for fabricating electrode systems in sensor and device development.

  19. Solution precursor plasma deposition of nanostructured ZnO coatings

    SciTech Connect

    Tummala, Raghavender; Guduru, Ramesh K.; Mohanty, Pravansu S.

    2011-08-15

    Highlights: {yields} The solution precursor route employed is an inexpensive process with capability to produce large scale coatings at fast rates on mass scale production. {yields} It is highly capable of developing tailorable nanostructures. {yields} This technique can be employed to spray the coatings on any kind of substrates including polymers. {yields} The ZnO coatings developed via solution precursor plasma spray process have good electrical conductivity and reflectivity properties in spite of possessing large amount of particulate boundaries, porosity and nanostructured grains. -- Abstract: Zinc oxide (ZnO) is a wide band gap semiconducting material that has various applications including optical, electronic, biomedical and corrosion protection. It is usually synthesized via processing routes, such as vapor deposition techniques, sol-gel, spray pyrolysis and thermal spray of pre-synthesized ZnO powders. Cheaper and faster synthesis techniques are of technological importance due to increased demand in alternative energy applications. Here, we report synthesis of nanostructured ZnO coatings directly from a solution precursor in a single step using plasma spray technique. Nanostructured ZnO coatings were deposited from the solution precursor prepared using zinc acetate and water/isopropanol. An axial liquid atomizer was employed in a DC plasma spray torch to create fine droplets of precursor for faster thermal treatment in the plasma plume to form ZnO. Microstructures of coatings revealed ultrafine particulate agglomerates. X-ray diffraction confirmed polycrystalline nature and hexagonal Wurtzite crystal structure of the coatings. Transmission electron microscopy studies showed fine grains in the range of 10-40 nm. Observed optical transmittance ({approx}65-80%) and reflectivity ({approx}65-70%) in the visible spectrum, and electrical resistivity (48.5-50.1 m{Omega} cm) of ZnO coatings are attributed to ultrafine particulate morphology of the coatings.

  20. Atmospheric Plasma Deposition of Diamond-like Carbon Coatings

    SciTech Connect

    Ladwig, Angela

    2008-01-23

    There is great demand for thin functional coatings in the semiconductor, optics, electronics, medical, automotive and aerospace industries [1-13]. As fabricated components become smaller and more complex, the properties of the materials’ surface take on greater importance. Thin coatings play a key role in tailoring surfaces to give them the desired hardness, wear resistance, chemical inertness, and electrical characteristics. Diamond-like carbon (DLC) coatings possess an array of desirable properties, including outstanding abrasion and wear resistance, chemical inertness, hardness, a low coefficient of friction and exceptionally high dielectric strength [14-22]. Diamond-like carbon is considered to be an amorphous material, containing a mixture of sp2 and sp3 bonded carbon. Based on the percentage of sp3 carbon and the hydrogen content, four different types of DLC coatings have been identified: tetrahedral carbon (ta-C), hydrogenated amorphous carbon (a-C:H) hard, a-C:H soft, and hydrogenated tetrahedral carbon (ta-C:H) [20,24,25]. Possessing the highest hardness of 80 GPa, ta-C possesses an sp3 carbon content of 80 to 88u%, and no appreciable hydrogen content whereas a-C:H soft possesses a hardness of less than 10 GPa, contains an sp3 carbon content of 60% and a hydrogen content between 30 to 50%. Methods used to deposit DLC coatings include ion beam deposition, cathodic arc spray, pulsed laser ablation, argon ion sputtering, and plasma-enhanced chemical vapor deposition [73-83]. Researchers contend that several advantages exist when depositing DLC coatings in a low-pressure environment. For example, ion beam processes are widely utilized since the ion bombardment is thought to promote denser sp3-bonded carbon networks. Other processes, such as sputtering, are better suited for coating large parts [29,30,44]. However, the deposition of DLC in a vacuum system has several disadvantages, including high equipment cost and restrictions on the size and shape of

  1. The non-anticoagulant heparin-like K5 polysaccharide derivative K5-N,OSepi attenuates myocardial ischaemia/reperfusion injury

    PubMed Central

    Collino, Massimo; Pini, Alessandro; Mastroianni, Rosanna; Benetti, Elisa; Lanzi, Cecilia; Bani, Daniele; Chini, Jacopo; Manoni, Marco; Fantozzi, Roberto; Masini, Emanuela

    2012-01-01

    Heparin and low molecular weight heparins have been demonstrated to reduce myocardial ischaemia/reperfusion (I/R) injury, although their use is hampered by the risk of haemorrhagic and thrombotic complications. Chemical and enzymatic modifications of K5 polysaccharide have shown the possibility of producing heparin-like compounds with low anticoagulant activity and strong anti-inflammatory effects. Using a rat model of regional myocardial I/R, we investigated the effects of an epimerized N-,O-sulphated K5 polysaccharide derivative, K5-N,OSepi, on infarct size and histological signs of myocardial injury caused by 30 min. ligature of the left anterior descending coronary artery followed by 1 or 24 h reperfusion. K5-N,OSepi (0.1–1 mg/kg given i.v. 15 min. before reperfusion) significantly reduced the extent of myocardial damage in a dose-dependent manner. Furthermore, we investigated the potential mechanism(s) of the cardioprotective effect(s) afforded by K5-N,OSepi. In left ventricular samples, I/R induced mast cell degranulation and a robust increase in lipid peroxidation, free radical-induced DNA damage and calcium overload. Markers of neutrophil infiltration and activation were also induced by I/R in rat hearts, specifically myeloperoxidase activity, intercellular-adhesion-molecule-1 expression, prostaglandin-E2 and tumour-necrosis-factor-α production. The robust increase in oxidative stress and inflammatory markers was blunted by K5-N,OSepi, in a dose-dependent manner, with maximum at 1 mg/kg. Furthermore, K5-N,OSepi administration attenuated the increase in caspase 3 activity, Bid and Bax activation and ameliorated the decrease in expression of Bcl-2 within the ischaemic myocardium. In conclusion, we demonstrate that the cardioprotective effect of the non-anticoagulant K5 derivative K5-N,OSepi is secondary to a combination of anti-apoptotic and anti-inflammatory effects. PMID:22248092

  2. Friction and wear of plasma-deposited diamond films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Wu, Richard L. C.; Garscadden, Alan; Barnes, Paul N.; Jackson, Howard E.

    1993-01-01

    Reciprocating sliding friction experiments in humid air and in dry nitrogen and unidirectional sliding friction experiments in ultrahigh vacuum were conducted with a natural diamond pin in contact with microwave-plasma-deposited diamond films. Diamond films with a surface roughness (R rms) ranging from 15 to 160 nm were produced by microwave-plasma-assisted chemical vapor deposition. In humid air and in dry nitrogen, abrasion occurred when the diamond pin made grooves in the surfaces of diamond films, and thus the initial coefficients of friction increased with increasing initial surface roughness. The equilibrium coefficients of friction were independent of the initial surface roughness of the diamond films. In vacuum the friction for diamond films contacting a diamond pin arose primarily from adhesion between the sliding surfaces. In these cases, the initial and equilibrium coefficients of friction were independent of the initial surface roughness of the diamond films. The equilibrium coefficients of friction were 0.02 to 0.04 in humid air and in dry nitrogen, but 1.5 to 1.8 in vacuum. The wear factor of the diamond films depended on the initial surface roughness, regardless of environment; it increased with increasing initial surface roughness. The wear factors were considerably higher in vacuum than in humid air and in dry nitrogen.

  3. Fluorinated carboxylic membranes deposited by plasma enhanced chemical vapour deposition for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Thery, J.; Martin, S.; Faucheux, V.; Le Van Jodin, L.; Truffier-Boutry, D.; Martinent, A.; Laurent, J.-Y.

    Among the fuel cell technologies, the polymer electrolyte membrane fuel cells (PEMFCs) are particularly promising because they are energy-efficient, clean, and fuel-flexible (i.e., can use hydrogen or methanol). The great majority of PEM fuel cells rely on a polymer electrolyte from the family of perfluorosulfonic acid membranes, nevertheless alternative materials are currently being developed, mainly to offer the alternative workout techniques which are required for the portable energy sources. Plasma polymerization represents a good solution, as it offers the possibility to deposit thin layer with an accurate and homogeneous thickness, even on 3D surfaces. In this paper, we present the results for the growth of proton conductive fluoro carboxylic membranes elaborated by plasma enhanced chemical vapour deposition. These membranes present conductivity values of the same order than the one of Nafion ®. The properties of the membrane, such as the chemical composition, the ionic conductivity, the swelling behaviour and the permeability were correlated to the plasma process parameters. The membranes were integrated in fuel cells on porous substrates and we present here the results regarding the barrier effect and the power output. Barrier effect similar to those of 40 μm Nafion ® layers was reached for 10 μm thick carboxylic membranes. Power outputs around 3 mW cm -2 were measured. We discuss the results regarding the gas barrier effect and the power outputs.

  4. Selective Plasma Deposition of Fluorocarbon Films on SAMs

    NASA Technical Reports Server (NTRS)

    Crain, Mark M., III; Walsh, Kevin M.; Cohn, Robert W.

    2006-01-01

    A dry plasma process has been demonstrated to be useful for the selective modification of self-assembled monolayers (SAMs) of alkanethiolates. These SAMs are used, during the fabrication of semiconductor electronic devices, as etch masks on gold layers that are destined to be patterned and incorporated into the devices. The selective modification involves the formation of fluorocarbon films that render the SAMs more effective in protecting the masked areas of the gold against etching by a potassium iodide (KI) solution. This modification can be utilized, not only in the fabrication of single electronic devices but also in the fabrication of integrated circuits, microelectromechanical systems, and circuit boards. In the steps that precede the dry plasma process, a silicon mold in the desired pattern is fabricated by standard photolithographic techniques. A stamp is then made by casting polydimethylsiloxane (commonly known as silicone rubber) in the mold. The stamp is coated with an alkanethiol solution, then the stamp is pressed on the gold layer of a device to be fabricated in order to deposit the alkanethiol to form an alkanethiolate SAM in the desired pattern (see figure). Next, the workpiece is exposed to a radio-frequency plasma generated from a mixture of CF4 and H2 gases. After this plasma treatment, the SAM is found to be modified, while the exposed areas of gold remain unchanged. This dry plasma process offers the potential for forming masks superior to those formed in a prior wet etching process. Among the advantages over the wet etching process are greater selectivity, fewer pin holes in the masks, and less nonuniformity of the masks. The fluorocarbon films formed in this way may also be useful as intermediate layers for subsequent fabrication steps and as dielectric layers to be incorporated into finished products.

  5. Plasma effects in aligned carbon nanoflake growth by plasma-enhanced hot filament chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Wang, B. B.; Zheng, K.; Cheng, Q. J.; Ostrikov, K.

    2015-01-01

    Carbon nanofilms are directly grown on silicon substrates by plasma-enhanced hot filament chemical vapor deposition in methane environment. It is shown that the nanofilms are composed of aligned carbon nanoflakes by extensive investigation of experimental results of field emission scanning electron microscopy, micro-Raman spectroscopy and transmission electron microscopy. In comparison with the graphene-like films grown without plasmas, the carbon nanoflakes grow in an alignment mode and the growth rate of the films is increased. The effects of the plasma on the growth of the carbon nanofilms are studied. The plasma plays three main effects of (1) promoting the separation of the carbon nanoflakes from the silicon substrate, (2) accelerating the motion of hydrocarbon radicals, and (3) enhancing the deposition of hydrocarbon ions onto the substrate surface. Due to these plasma-specific effects, the carbon nanofilms can be formed from the aligned carbon nanoflakes with a high rate. These results advance our knowledge on the synthesis, properties and applications of graphene-based materials.

  6. High-density plasma deposition manufacturing productivity improvement

    NASA Astrophysics Data System (ADS)

    Olmer, Leonard J.; Hudson, Chris P.

    1999-09-01

    High Density Plasma (HDP) deposition provides a means to deposit high quality dielectrics meeting submicron gap fill requirements. But, compared to traditional PECVD processing, HDP is relatively expensive due to the higher capital cost of the equipment. In order to keep processing costs low, it became necessary to maximize the wafer throughput of HDP processing without degrading the film properties. The approach taken was to optimize the post deposition microwave in-situ clean efficiency. A regression model, based on actual data, indicated that number of wafers processed before a chamber clean was the dominant factor. Furthermore, a design change in the ceramic hardware, surrounding the electrostatic chuck, provided thermal isolation resulting in an enhanced clean rate of the chamber process kit. An infra-red detector located in the chamber exhaust line provided a means to endpoint the clean and in-film particle data confirmed the infra-red results. The combination of increased chamber clean frequency, optimized clean time and improved process.

  7. Crystal Nucleation in Plasma Deposited Dlc Coatings during Annealing

    NASA Astrophysics Data System (ADS)

    Chaliampalias, D.; Pavlidou, E.; Psyllaki, P.; Chrissafis, K.; Vourlias, G.

    2010-01-01

    Diamond-like carbon (DLC) films, hard carbon coatings, with unique physical and mechanical properties which approach those of natural diamond, such as high hardness, low coefficient of friction and chemical inertness. In several applications, heavy loads and high friction forces are generated and lead to local temperature increase. In such cases these coatings must be thermal stable and with enhanced high temperature oxidation resistance in order to be good candidates for wear protection of metallic components. In the present study a radio frequency plasma deposition system was used for the deposition of 2 μm-thick amorphous DLC coatings onto AISI D2 substrates. The as deposited DLC covered samples were dense, homogeneous and well bonded to the substrate, while no cracks were observed. In order to study the thermal stability of the coatings' DLC nature, in-situ Transmission Electron Microscopic (TEM) observations were carried out during slow annealing of the specimen in the microscope vacuum chamber, as well as thermo-gravimetric (TG) measurements in argon atmosphere, up to 800° C. The first crystallites appeared within the DLC amorphous matrix at about 450° C as surface crystallization, while the mass crystallization started at 600° C as the TG measurements indicated. Finally, the nucleation was completed at 700° C. The oxidation results, performed from ambient temperature up to 1000° C, showed that DLC covered coupons are remarkably resistant as their mass gain was significantly lower than that of the uncovered substrates.

  8. Pulsed and continuous wave acrylic acid radio frequency plasma deposits: plasma and surface chemistry.

    PubMed

    Voronin, Sergey A; Zelzer, Mischa; Fotea, Catalin; Alexander, Morgan R; Bradley, James W

    2007-04-01

    Plasma polymers have been formed from acrylic acid using a pulsed power source. An on-pulse duration of 100 micros was used with a range of discharge off-times between 0 (continuous wave) and 20,000 micros. X-ray photoelectron spectroscopy (XPS) has been used in combination with trifluoroethanol (TFE) derivatization to quantify the surface concentration of the carboxylic acid functionality in the deposit. Retention of this functionality from the monomer varied from 2% to 65%. When input power was expressed as the time-averaged energy per monomer molecule, E(mean), the deposit chemistry achieved could be described using a single relationship for all deposition conditions. Deposition rates were monitored using a quartz crystal microbalance, which revealed a range from 20 to 200 microg m(-2) s(-1), and these fell as COOH functional retention increased. The flow rate was found to be the major determinant of the deposition rate, rather than being uniquely defined by E(mean), connected to the rate at which fresh monomer enters the system in the monomer deficient regime. The neutral species were collected in a time-averaged manner. As the energy delivered per molecule in the system (E(mean)) decreased, the amount of intact monomer increased, with the average neutral mass approaching 72 amu as E(mean) tends to zero. No neutral oligomeric species were detected. Langmuir probes have been used to determine the temporal evolution of the density and temperature of the electrons in the plasma and the plasma potential adjacent to the depositing film. It has been found that even 500 micros into the afterglow period that ionic densities are still significant, 5-10% of the on-time density, and that ion accelerating sheath potentials fall from 40 V in the on-time to a few volts in the off-time. We have made the first detailed, time- and energy-resolved mass spectrometry measurements in depositing acrylic acid plasma. These have allowed us to identify and quantify the positive ion

  9. Deposition of aligned bamboo-like carbon nanotubes via microwave plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Cui, H.; Zhou, O.; Stoner, B. R.

    2000-11-01

    Aligned multiwall carbon nanotubes have been grown on silicon substrates by microwave plasma enhanced chemical vapor deposition using methane/ammonia mixtures. Scanning electron microscopy shows that the nanotubes are well aligned with high aspect ratio and growth direction normal to the substrate. Transmission electron microscopy reveals that the majority phase has a bamboo-like structure. Data are also presented showing process variable effects on the size and microstructure of the aligned nanotubes, giving insight into possible nucleation and growth mechanisms for the process.

  10. Mathematical modeling of plasma deposition and hardening of coatings-switched electrical parameters

    NASA Astrophysics Data System (ADS)

    Kadyrmetov, A. M.; Sharifullin, S. N.; Pustovalov, AS

    2016-01-01

    This paper presents the results of simulation of plasma deposition and hardening of coatings in modulating the electrical parameters. Mathematical models are based on physical models of gas-dynamic mechanisms more dynamic and thermal processes of the plasma jet. As an example the modeling of dynamic processes of heterogeneous plasma jet, modulated current pulses indirect arc plasma torch.

  11. Carbon Nanotubes/Nanofibers by Plasma Enhanced Chemical Vapour Deposition

    NASA Technical Reports Server (NTRS)

    Teo, K. B. K.; Hash, D. B.; Bell, M. S.; Chhowalla, M.; Cruden, B. A.; Amaratunga, G. A. J.; Meyyappan, M.; Milne, W. I.

    2005-01-01

    Plasma enhanced chemical vapour deposition (PECVD) has been recently used for the production of vertically aligned carbon nanotubedfibers (CN) directly on substrates. These structures are potentially important technologically as electron field emitters (e.g. microguns, microwave amplifiers, displays), nanoelectrodes for sensors, filter media, superhydrophobic surfaces and thermal interface materials for microelectronics. A parametric study on the growth of CN grown by glow discharge dc-PECVD is presented. In this technique, a substrate containing thin film Ni catalyst is exposed to C2H2 and NH3 gases at 700 C. Without plasma, this process is essentially thermal CVD which produces curly spaghetti-like CN as seen in Fig. 1 (a). With the plasma generated by biasing the substrate at -6OOV, we observed that the CN align vertically during growth as shown in Fig. l(b), and that the magnitude of the applied substrate bias affects the degree of alignment. The thickness of the thin film Ni catalyst was found to determine the average diameter and inversely the length of the CN. The yield and density of the CN were controlled by the use of different diffusion barrier materials under the Ni catalyst. Patterned CN growth [Fig. l(c)], with la variation in CN diameter of 4.1% and 6.3% respectively, is achieved by lithographically defining the Ni thin film prior to growth. The shape of the structures could be varied from very straight nanotube-like to conical tip-like nanofibers by increasing the ratio of C2H2 in the gas flow. Due to the plasma decomposition of C2H2, amorphous carbon (a-C) is an undesirable byproduct which could coat the substrate during CN growth. Using a combination of depth profiled Auger electron spectroscopy to study the substrate and in-situ mass spectroscopy to examine gas phase neutrals and ions, the optimal conditions for a-C free growth of CN is determined.

  12. Effect of deposition conditions on properties of plasma polymerized carbon disulfide

    SciTech Connect

    Sadhir, R.K.; Schoch, K.F. Jr.

    1995-12-31

    This paper discusses the results on deposition conditions, rates of polymerization and properties of carbon disulfide films prepared by two techniques viz. plasma polymerization and argon-plasma-assisted polymerization of carbon disulfide. A higher rate of polymerization and sulfur content was obtained for carbon disulfide films prepared by plasma polymerization technique. The ultimate objective of this research work was to prepare thin film solid state batteries using the optimized carbon disulfide polymer films deposited by plasma techniques, as active material.

  13. Dielectric properties of 'diamondlike' carbon prepared by RF plasma deposition

    NASA Technical Reports Server (NTRS)

    Lamb, J. D.; Woollam, J. A.

    1985-01-01

    Metal-carbon-metal structures were fabricated using either gold or aluminum evaporated electrodes and RF plasma (methane) deposited 'diamondlike' carbon films. Alternating-current conductance and capacitance versus voltage and frequency (10 Hz to 13 MHz) data were taken to determine the dielectric properties of these films. Conductance versus frequency data fit a generalized power law, consistent with both dc and hopping conduction components. The capacitance versus frequency data are well matched to the conductance versus frequency data, as predicted by a Kramers-Kronig analysis. The dielectric loss tangent is nearly constant at 0.5 to 1.0 percent over the frequency range from 1 to 100 kHz. The dc resistivity is above 10 to the 13th ohm cm, and the dc breakdown strength is above 8 x 10 to the 6th V/cm is properly prepared samples.

  14. Growth of graphene films by plasma enhanced chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Baraton, Laurent; Gangloff, Laurent; Xavier, Stéphane; Cojocaru, Costel S.; Huc, Vincent; Legagneux, Pierre; Lee, Young Hee; Pribat, Didier

    2009-08-01

    Since it was isolated in 2004, graphene, the first known 2D crystal, is the object of a growing interest, due to the range of its possible applications as well as its intrinsic properties. From large scale electronics and photovoltaics to spintronics and fundamental quantum phenomena, graphene films have attracted a large community of researchers. But bringing graphene to industrial applications will require a reliable, low cost and easily scalable synthesis process. In this paper we present a new growth process based on plasma enhanced chemical vapor deposition. Furthermore, we show that, when the substrate is an oxidized silicon wafer covered by a nickel thin film, graphene is formed not only on top of the nickel film, but also at the interface with the supporting SiO2 layer. The films grown using this method were characterized using classical methods (Raman spectroscopy, AFM, SEM) and their conductivity is found to be close to those reported by others.

  15. Coaxial carbon plasma gun deposition of amorphous carbon films

    NASA Technical Reports Server (NTRS)

    Sater, D. M.; Gulino, D. A.; Rutledge, S. K.

    1984-01-01

    A unique plasma gun employing coaxial carbon electrodes was used in an attempt to deposit thin films of amorphous diamond-like carbon. A number of different structural, compositional, and electrical characterization techniques were used to characterize these films. These included scanning electron microscopy, scanning transmission electron microscopy, X ray diffraction and absorption, spectrographic analysis, energy dispersive spectroscopy, and selected area electron diffraction. Optical absorption and electrical resistivity measurements were also performed. The films were determined to be primarily amorphous, with poor adhesion to fused silica substrates. Many inclusions of particulates were found to be present as well. Analysis of these particulates revealed the presence of trace impurities, such as Fe and Cu, which were also found in the graphite electrode material. The electrodes were the source of these impurities. No evidence of diamond-like crystallite structure was found in any of the film samples. Details of the apparatus, experimental procedure, and film characteristics are presented.

  16. Low Temperature Deposition of β-phase Silicon Nitride Using Inductively Coupled Plasma Chemical Vapor Deposition Technique

    NASA Astrophysics Data System (ADS)

    Kshirsagar, Abhijeet; Duttagupta, S. P.; Gangal, S. A.

    2010-12-01

    Silicon nitride (SiN) films have been deposited at low temperature (≤100° C), by Inductively Coupled Plasma Chemical Vapor Deposition (ICPCVD) technique. The chemical and physical properties of deposited SiN films such as refractive index, deposition rate, and film stress have been measured. Additional structural characterization is performed using X-ray diffraction (XRD) and Micro Raman Spectroscopy. It is found that the films obtained are of low stress and have β-phase. To the best of authors knowledge such low temperature, low stress, β-phase SiN films deposition using ICPCVD are being reported for the first time.

  17. High growth rate homoepitaxial diamond film deposition at high temperatures by microwave plasma-assisted chemical vapor deposition

    NASA Technical Reports Server (NTRS)

    Vohra, Yogesh K. (Inventor); McCauley, Thomas S. (Inventor)

    1997-01-01

    The deposition of high quality diamond films at high linear growth rates and substrate temperatures for microwave-plasma chemical vapor deposition is disclosed. The linear growth rate achieved for this process is generally greater than 50 .mu.m/hr for high quality films, as compared to rates of less than 5 .mu.m/hr generally reported for MPCVD processes.

  18. High Temperature Multilayer Environmental Barrier Coatings Deposited Via Plasma Spray-Physical Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Harder, Bryan James; Zhu, Dongming; Schmitt, Michael P.; Wolfe, Douglas E.

    2014-01-01

    Si-based ceramic matrix composites (CMCs) require environmental barrier coatings (EBCs) in combustion environments to avoid rapid material loss. Candidate EBC materials have use temperatures only marginally above current technology, but the addition of a columnar oxide topcoat can substantially increase the durability. Plasma Spray-Physical Vapor Deposition (PS-PVD) allows application of these multilayer EBCs in a single process. The PS-PVD technique is a unique method that combines conventional thermal spray and vapor phase methods, allowing for tailoring of thin, dense layers or columnar microstructures by varying deposition conditions. Multilayer coatings were deposited on CMC specimens and assessed for durability under high heat flux and load. Coated samples with surface temperatures ranging from 2400-2700F and 10 ksi loads using the high heat flux laser rigs at NASA Glenn. Coating morphology was characterized in the as-sprayed condition and after thermomechanical loading using electron microscopy and the phase structure was tracked using X-ray diffraction.

  19. Ablation Plasma Ion Implantation Optimization and Deposition of Compound Coatings

    NASA Astrophysics Data System (ADS)

    Jones, M. C.; Qi, B.; Gilgenbach, R. M.; Johnston, M. D.; Lau, Y. Y.; Doll, G. L.; Lazarides, A.

    2002-10-01

    Ablation Plasma Ion Implantation (APII) utilizes KrF laser ablation plasma plumes to implant ions into pulsed, negatively-biased substrates [1]. Ablation targets are Ti foils and TiN disks. Substrates are Si wafers and Al, biased from 0 to -10 kV. Optimization experiments address: 1) configurations that reduce arcing, 2) reduction of particulate, and 3) deposition/implantation of compounds (e.g. TiN). Arcing is suppressed by positioning the target perpendicular (previously parallel) to the substrate. Thus, bias voltage can be applied at the same time as the KrF laser, resulting in higher ion current. This geometry also yields lower particulate. APII with TiN has the goal of hardened coatings with excellent adhesion. SEM, AFM, XPS, TEM, and scratch tests characterize properties of the thin films. Ti APII films at - 4kV are smoother with lower friction. 1. B. Qi, R.M. Gilgenbach, Y.Y. Lau, M.D. Johnston, J. Lian, L.M. Wang, G. L. Doll and A. Lazarides, APL, 78, 3785 (2001) * Research funded by NSF

  20. Computer simulation of plasma for plasma immersed ion implantation and deposition with bipolar pulses

    NASA Astrophysics Data System (ADS)

    Miyagawa, Y.; Ikeyama, M.; Miyagawa, S.; Nakadate, H.

    2003-05-01

    In order to analyze the plasma behavior under the plasma immersion ion implantation and deposition (PIII&D) condition, a newly developed simulation software "PEGASUS" has been used. The spatial distributions of potential, ion and electron density were calculated for trench-shaped target immersed in Ar plasma (1 mTorr, 10 10 cm -3). The obtained time dependence of sheath length agreed with the analytical results based on Child-Langmuir theory. In the bipolar pulse PIII&D system, a positive- and a negative- pulse voltage are applied alternately to a target, instead of negative pulses used in the conventional PIII&D method. Using simulation, the following results were obtained; when a negative pulse voltage is applied to a target, a weak plasma is generated around the target. In contrast, when a positive pulse voltage is applied, a more intense plasma is generated under the same conditions. The results obtained by simulation of the behavior of ions and electrons near a trench-shaped target are presented.

  1. Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor deposition

    SciTech Connect

    Bartlome, Richard De Wolf, Stefaan; Demaurex, Bénédicte; Ballif, Christophe; Amanatides, Eleftherios; Mataras, Dimitrios

    2015-05-28

    We clarify the difference between the SiH{sub 4} consumption efficiency η and the SiH{sub 4} depletion fraction D, as measured in the pumping line and the actual reactor of an industrial plasma-enhanced chemical vapor deposition system. In the absence of significant polysilane and powder formation, η is proportional to the film growth rate. Above a certain powder formation threshold, any additional amount of SiH{sub 4} consumed translates into increased powder formation rather than into a faster growing Si film. In order to discuss a zero-dimensional analytical model and a two-dimensional numerical model, we measure η as a function of the radio frequency (RF) power density coupled into the plasma, the total gas flow rate, the input SiH{sub 4} concentration, and the reactor pressure. The adjunction of a small trimethylboron flow rate increases η and reduces the formation of powder, while the adjunction of a small disilane flow rate decreases η and favors the formation of powder. Unlike η, D is a location-dependent quantity. It is related to the SiH{sub 4} concentration in the plasma c{sub p}, and to the phase of the growing Si film, whether the substrate is glass or a c-Si wafer. In order to investigate transient effects due to the RF matching, the precoating of reactor walls, or the introduction of a purifier in the gas line, we measure the gas residence time and acquire time-resolved SiH{sub 4} density measurements throughout the ignition and the termination of a plasma.

  2. Radio frequency plasma power dependence of the moisture permeation barrier characteristics of Al{sub 2}O{sub 3} films deposited by remote plasma atomic layer deposition

    SciTech Connect

    Jung, Hyunsoo; Samsung Display Co. Ltd., Tangjeong, Chungcheongnam-Do 336-741 ; Choi, Hagyoung; Lee, Sanghun; Jeon, Heeyoung; Jeon, Hyeongtag; Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791

    2013-11-07

    In the present study, we investigated the gas and moisture permeation barrier properties of Al{sub 2}O{sub 3} films deposited on polyethersulfone films (PES) by capacitively coupled plasma (CCP) type Remote Plasma Atomic Layer Deposition (RPALD) at Radio Frequency (RF) plasma powers ranging from 100 W to 400 W in 100 W increments using Trimethylaluminum [TMA, Al(CH{sub 3}){sub 3}] as the Al source and O{sub 2} plasma as the reactant. To study the gas and moisture permeation barrier properties of 100-nm-thick Al{sub 2}O{sub 3} at various plasma powers, the Water Vapor Transmission Rate (WVTR) was measured using an electrical Ca degradation test. WVTR decreased as plasma power increased with WVTR values for 400 W and 100 W of 2.6 × 10{sup −4} gm{sup −2}day{sup −1} and 1.2 × 10{sup −3} gm{sup −2}day{sup −1}, respectively. The trends for life time, Al-O and O-H bond, density, and stoichiometry were similar to that of WVTR with improvement associated with increasing plasma power. Further, among plasma power ranging from 100 W to 400 W, the highest power of 400 W resulted in the best moisture permeation barrier properties. This result was attributed to differences in volume and amount of ion and radical fluxes, to join the ALD process, generated by O{sub 2} plasma as the plasma power changed during ALD process, which was determined using a plasma diagnosis technique called the Floating Harmonic Method (FHM). Plasma diagnosis by FHM revealed an increase in ion flux with increasing plasma power. With respect to the ALD process, our results indicated that higher plasma power generated increased ion and radical flux compared with lower plasma power. Thus, a higher plasma power provides the best gas and moisture permeation barrier properties.

  3. No primexine and plasma membrane undulation is essential for primexine deposition and plasma membrane undulation during microsporogenesis in Arabidopsis.

    PubMed

    Chang, Hai-Shuang; Zhang, Cheng; Chang, Yu-Hua; Zhu, Jun; Xu, Xiao-Feng; Shi, Zhi-Hao; Zhang, Xiao-Lei; Xu, Ling; Huang, Hai; Zhang, Sen; Yang, Zhong-Nan

    2012-01-01

    Primexine deposition and plasma membrane undulation are the initial steps of pollen wall formation. However, little is known about the genes involved in this important biological process. Here, we report a novel gene, NO PRIMEXINE AND PLASMA MEMBRANE UNDULATION (NPU), which functions in the early stage of pollen wall development in Arabidopsis (Arabidopsis thaliana). Loss of NPU function causes male sterility due to a defect in callose synthesis and sporopollenin deposition, resulting in disrupted pollen in npu mutants. Transmission electronic microscopy observation demonstrated that primexine deposition and plasma membrane undulation are completely absent in the npu mutants. NPU encodes a membrane protein with two transmembrane domains and one intracellular domain. In situ hybridization analysis revealed that NPU is strongly expressed in microspores and the tapetum during the tetrad stage. All these results together indicate that NPU plays a vital role in primexine deposition and plasma membrane undulation during early pollen wall development. PMID:22100644

  4. Analysis of hydrogen plasma in a microwave plasma chemical vapor deposition reactor

    NASA Astrophysics Data System (ADS)

    Shivkumar, G.; Tholeti, S. S.; Alrefae, M. A.; Fisher, T. S.; Alexeenko, A. A.

    2016-03-01

    The aim of this work is to build a numerical model of hydrogen plasma inside a microwave plasma chemical vapor deposition system. This model will help in understanding and optimizing the conditions for the growth of carbon nanostructures. A 2D axisymmetric model of the system is implemented using the finite element high frequency Maxwell solver and the heat transfer solver in COMSOL Multiphysics. The system is modeled to study variation in parameters with reactor geometry, microwave power, and gas pressure. The results are compared with experimental measurements from the Q-branch of the H2 Fulcher band of hydrogen using an optical emission spectroscopy technique. The parameter γ in Füner's model is calibrated to match experimental observations at a power of 500 W and 30 Torr. Good agreement is found between the modeling and experimental results for a wide range of powers and pressures. The gas temperature exhibits a weak dependence on power and a strong dependence on gas pressure. The inclusion of a vertical dielectric pillar that concentrates the plasma increases the maximum electron temperature by 70%, the maximum gas temperature by 50%, and the maximum electron number density by 70% when compared to conditions without the pillar at 500 W and 30 Torr. Experimental observations also indicate intensified plasma with the inclusion of a pillar.

  5. Characterization of Carbon Deposits Formed During Plasma Pyrolysis of Xinjiang Candle Coal

    NASA Astrophysics Data System (ADS)

    Zhu, Guilin; Meng, Yuedong; Shu, Xingsheng; Fang, Shidong

    2009-08-01

    Carbon deposits were formed on the reactor wall during plasma pyrolysis of the Xinjiang candle coal in our V-style plasma pyrolysis pilot-plant. The carbon deposits were studied using a scanning electronic microscope (SEM) and the X-ray diffraction (XRD) method. It was found that carbon deposits located at different parts in the reactor exhibited different microscopic patterns. The formation mechanism of the carbon deposits was deduced. The downward increase in the graphitization degree of the carbon deposits was found and interpreted.

  6. Deposition of materials using a plasma focus of tens of joules

    NASA Astrophysics Data System (ADS)

    Inestrosa-Izurieta, M. J.; Jauregui, P.; Soto, L.

    2016-05-01

    Physical properties of transient plasmas, energetic ions and electrons, as produced in plasma focus (PF) discharges are substantially different than the conventional plasma devices used for plasma nanofabrication. In particular, PF discharges provide new and unique opportunities in processing and synthesis of new materials. Since PF discharges have very short duration and produce plasmas of high ion density, the anode is exposed to a high energy density causing its pulverization and generating a vapour of material that allows a fast deposit. In this paper a table top plasma focus of tens of joules, PF-50J, was used to produce material deposition. First deposits obtained from detached anode material (steel) or a metallic insert (titanium) from the plasma ejected after the pinch in the axial direction are presented.

  7. Effect of plasma parameters on characteristics of silicon nitride film deposited by single and dual frequency plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Sahu, B. B.; Yin, Yongyi; Han, Jeon G.

    2016-03-01

    This work investigates the deposition of hydrogenated amorphous silicon nitride films using various low-temperature plasmas. Utilizing radio-frequency (RF, 13.56 MHz) and ultra-high frequency (UHF, 320 MHz) powers, different plasma enhanced chemical vapor deposition processes are conducted in the mixture of reactive N2/NH3/SiH4 gases. The processes are extensively characterized using different plasma diagnostic tools to study their plasma and radical generation capabilities. A typical transition of the electron energy distribution function from single- to bi-Maxwellian type is achieved by combining RF and ultra-high powers. Data analysis revealed that the RF/UHF dual frequency power enhances the plasma surface heating and produces hot electron population with relatively low electron temperature and high plasma density. Using various film analysis methods, we have investigated the role of plasma parameters on the compositional, structural, and optical properties of the deposited films to optimize the process conditions. The presented results show that the dual frequency power is effective for enhancing dissociation and ionization of neutrals, which in turn helps in enabling high deposition rate and improving film properties.

  8. Electrochromic Devices Deposited on Low-Temperature Plastics by Plasma-Enhanced Chemical Vapor Deposition

    SciTech Connect

    Robbins, Joshua; Seman, Michael

    2005-09-20

    Electrochromic windows have been identified by the Basic energy Sciences Advisory committee as an important technology for the reduction of energy spent on heating and cooling in residential and commercial buildings. Electrochromic devices have the ability to reversibly alter their optical properties in response to a small electric field. By blocking ultraviolet and infrared radiation, while modulating the incoming visible radiation, electrochromics could reduce energy consumption by several Quads per year. This amounts to several percent of the total annual national energy expenditures. The purpose of this project was to demonstrate proof of concept for using plasma-enhanced chemical vapor deposition (PECVD) for depositing all five layers necessary for full electrochromic devices, as an alternative to sputtering techniques. The overall goal is to produce electrochromic devices on flexible polymer substrates using PECVD to significantly reduce the cost of the final product. We have successfully deposited all of the films necessary for a complete electrochromic devices using PECVD. The electrochromic layer, WO3, displayed excellent change in visible transmission with good switching times. The storage layer, V2O5, exhibited a high storage capacity and good clear state transmission. The electrolyte, Ta2O5, was shown to functional with good electrical resistivity to go along with the ability to transfer Li ions. There were issues with leakage over larger areas, which can be address with further process development. We developed a process to deposit ZnO:Ga with a sheet resistance of < 50 W/sq. with > 90% transmission. Although we were not able to deposit on polymers due to the temperatures required in combination with the inverted position of our substrates. Two types of full devices were produced. Devices with Ta2O5 were shown to be functional using small aluminum dots as the top contact. The polymer electrolyte devices were shown to have a clear state transmission of

  9. Influence of emitter temperature on the energy deposition in a low-pressure plasma

    NASA Astrophysics Data System (ADS)

    Levko, Dmitry; Raja, Laxminarayan L.

    2016-03-01

    The influence of emitter temperature on the energy deposition into low-pressure plasma is studied by the self-consistent one-dimensional Particle-in-Cell Monte Carlo Collisions model. Depending on the emitter temperature, different modes of discharge operation are obtained. The mode type depends on the plasma frequency and does not depend on the ratio between the densities of beam and plasma electrons. Namely, plasma is stable when the plasma frequency is small. For this plasma, the energy transfer from emitted electrons to plasma electrons is inefficient. The increase in the plasma frequency results first in the excitation of two-stream electron instability. However, since the thermal velocity of plasma electrons is smaller than the electrostatic wave velocity, the resonant wave-particle interaction is inefficient for the energy deposition into the plasma. Further increase in the plasma frequency leads to the distortion of beam of emitted electrons. Then, the electrostatic wave generated due to two-stream instability decays into multiple slower waves. Phase velocities of these waves are comparable with the thermal velocity of plasma electrons which makes possible the resonant wave-particle interaction. This results in the efficient energy deposition from emitted electrons into the plasma.

  10. Optical emission study of a doped diamond deposition process by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Rayar, M.; Supiot, P.; Veis, P.; Gicquel, A.

    2008-08-01

    Standard H2/CH4/B2H6 plasmas (99% of H2 and 1% of CH4, with 0-100ppm of B2H6 added) used for doped diamond film growth are studied by optical emission spectroscopy in order to gain a better understanding of the influence of boron species on the gas phase chemistry. Only two boron species are detected under our experimental conditions (9/15/23Wcm-3 average microwave power density values), and the emission spectra used for studies reported here are B(S1/22-P1/2,3/202) and BH [AΠ1-XΣ+1(0,0)]. Variations of their respective emission intensities as a function of the ratio B /C, the boron to carbon ratio in the gas mixture, are reported. We confirmed that the plasma parameters (Tg, Te, and ne) are not affected by the introduction of diborane, and the number densities of B atoms and BH radical species were estimated from experimental measurements. The results are compared to those obtained from a zero-dimensional chemical kinetic model where two groups of reactions are considered: (1) BHx+H ↔BHx -1+H2 (x=1-3) by analogy with the well-known equilibrium CHx+H set of reactions, which occurs, in particular, in diamond deposition reactors; and (2) from conventional organic chemistry, the set of reactions involving boron species: BHx+C2H2 (x =0-1). The results clearly show that the model based on hydrogen and boron hydrides reactions alone is not consistent with the experimental results, while it is so when taking into account both sets of reactions. Once an upper limit for the boron species number densities has been estimated, axial profiles are calculated on the basis of the plasma model results obtained previously in Laboratoire d'Ingénierie des Matériaux et des Hautes Pressions, and significant differences in trends for different boron species are found. At the plasma-to-substrate boundary, [BH] and [B] drop off in contrast to [BH2], which shows little decrease, and [BH3], which shows little increase, in this region.

  11. Vertically aligned peptide nanostructures using plasma-enhanced chemical vapor deposition.

    PubMed

    Vasudev, Milana C; Koerner, Hilmar; Singh, Kristi M; Partlow, Benjamin P; Kaplan, David L; Gazit, Ehud; Bunning, Timothy J; Naik, Rajesh R

    2014-02-10

    In this study, we utilize plasma-enhanced chemical vapor deposition (PECVD) for the deposition of nanostructures composed of diphenylalanine. PECVD is a solvent-free approach and allows sublimation of the peptide to form dense, uniform arrays of peptide nanostructures on a variety of substrates. The PECVD deposited d-diphenylalanine nanostructures have a range of chemical and physical properties depending on the specific discharge parameters used during the deposition process. PMID:24400716

  12. Microstructure and characterization of a novel cobalt coating prepared by cathode plasma electrolytic deposition

    NASA Astrophysics Data System (ADS)

    Quan, Cheng; He, Yedong

    2015-10-01

    A novel cobalt coating was prepared by cathode plasma electrolytic deposition (CPED). The kinetics of the electrode process in cathode plasma electrolytic deposition was studied. The composition and microstructure of the deposited coatings were investigated by SEM, EDS, XRD and TEM. The novel cobalt coatings were dense and uniform, showing a typically molten morphology, and were deposited with a rather fast rate. Different from the coatings prepared by conventional electrodeposition or chemical plating, pure cobalt coatings with face center cubic (fcc) structure were obtained by CPED. The deposited coatings were nanocrystalline structure with an average grain size of 40-50 nm, exhibited high hardness, excellent adhesion with the stainless steels, and superior wear resistance. The properties of the novel cobalt coatings prepared by CPED have been improved significantly, as compared with that prepared by conventional methods. It reveals that cathode plasma electrolytic deposition is an effective way to prepare novel cobalt coatings with high quality.

  13. Experimental investigation on geometrical aspects of micro-plasma deposited tool steel for repair applications

    NASA Astrophysics Data System (ADS)

    Jhavar, S.; Paul, C. P.; Jain, N. K.

    2014-08-01

    Recent advancement in direct material deposition processes found wide applications in rapid prototyping, manufacturing and tooling industry. Micro-plasma deposition is one of the recent developments in this domain. This paper reports the deployment of newly integrated micro-plasma deposition system for the deposition of AISI P-20 tool steel on the AISI P20 tool steel substrate. A number of test tracks for single track deposition were deposited at the various combination of processing parameters. The sets of parameters yielding good deposits were selected to deposit overlap tracks. The geometry of single and overlapped tracks was evaluated to understand the parametric dependence. The study indicates that the aspect ratio of track geometry (ratio of width to height of track) is dependent on the processing parameters and the discharge current is identified as the most dominating parameters (contribution = 44%), followed by scan speed (contribution = 26.68%) and wire feed rate (contribution = 26.98%) with almost same effect. The microscopic study of the deposits indicates that the material deposited at the optimum processing parameters is free from surface and bulk defects. The estimated material properties are found to be at par with conventional processed material. This feasibility study proved that the micro-plasma deposition can be used for the generation of surfaces and multi-featured material deposition. It paved a way for the application of the process in die/mold repairs.

  14. Deposition of dielectric films on silicon using a fore-vacuum plasma electron source

    NASA Astrophysics Data System (ADS)

    Zolotukhin, D. B.; Oks, E. M.; Tyunkov, A. V.; Yushkov, Yu. G.

    2016-06-01

    We describe an experiment on the use of a fore-vacuum-pressure, plasma-cathode, electron beam source with current up to 100 mA and beam energy up to 15 keV for deposition of Mg and Al oxide films on Si substrates in an oxygen atmosphere at a pressure of 10 Pa. The metals (Al and Mg) were evaporated and ionized using the electron beam with the formation of a gas-metal beam-plasma. The plasma was deposited on the surface of Si substrates. The elemental composition of the deposited films was analyzed.

  15. Deposition of diamond-like carbon film using electron cyclotron resonance plasma

    NASA Astrophysics Data System (ADS)

    Kuo, S. C.; Kunhardt, E. E.; Srivatsa, A. R.

    1991-11-01

    Hard diamond-like carbon films were deposited on Si(100) substrates using a CH4 plasma created through electron cyclotron resonance (ECR) heating. The ECR plasma was excited by a Lisitano coil. These films could be deposited with a negative dc bias (-200 V) or a RF-induced negative self-bias (-100 V) on the substrates. The deposition rate of the film was about 2.3 A/s. The deposited films were characterized by Raman spectroscopy and near-edge X-ray absorption fine structure analysis.

  16. Deposition of diamond-like carbon film using electron cyclotron resonance plasma

    SciTech Connect

    Kuo, S.C.; Kunhardt, E.E. ); Srivatsa, A.R. )

    1991-11-11

    Hard diamond-like carbon films were deposited on Si(100) substrates using a CH{sub 4} plasma created through electron cyclotron resonance (ECR) heating. The ECR plasma was excited by a Lisitano coil. These films could be deposited with a negative dc bias ({minus}200 V) or a rf-induced negative self-bias ({minus}100 V) on the substrates. The deposition rate of the film was about 2.3 A/s. The deposited films were characterized by Raman spectroscopy and near-edge x-ray absorption fine structure analysis.

  17. Role of plasma enhanced atomic layer deposition reactor wall conditions on radical and ion substrate fluxes

    SciTech Connect

    Sowa, Mark J.

    2014-01-15

    Chamber wall conditions, such as wall temperature and film deposits, have long been known to influence plasma source performance on thin film processing equipment. Plasma physical characteristics depend on conductive/insulating properties of chamber walls. Radical fluxes depend on plasma characteristics as well as wall recombination rates, which can be wall material and temperature dependent. Variations in substrate delivery of plasma generated species (radicals, ions, etc.) impact the resulting etch or deposition process resulting in process drift. Plasma enhanced atomic layer deposition is known to depend strongly on substrate radical flux, but film properties can be influenced by other plasma generated phenomena, such as ion bombardment. In this paper, the chamber wall conditions on a plasma enhanced atomic layer deposition process are investigated. The downstream oxygen radical and ion fluxes from an inductively coupled plasma source are indirectly monitored in temperature controlled (25–190 °C) stainless steel and quartz reactors over a range of oxygen flow rates. Etch rates of a photoresist coated quartz crystal microbalance are used to study the oxygen radical flux dependence on reactor characteristics. Plasma density estimates from Langmuir probe ion saturation current measurements are used to study the ion flux dependence on reactor characteristics. Reactor temperature was not found to impact radical and ion fluxes substantially. Radical and ion fluxes were higher for quartz walls compared to stainless steel walls over all oxygen flow rates considered. The radical flux to ion flux ratio is likely to be a critical parameter for the deposition of consistent film properties. Reactor wall material, gas flow rate/pressure, and distance from the plasma source all impact the radical to ion flux ratio. These results indicate maintaining chamber wall conditions will be important for delivering consistent results from plasma enhanced atomic layer deposition

  18. Plasma sheath physics and dose uniformity in enhanced glow discharge plasma immersion ion implantation and deposition

    SciTech Connect

    Li Liuhe; Li Jianhui; Kwok, Dixon T. K.; Chu, Paul K.; Wang Zhuo

    2009-07-01

    Based on the multiple-grid particle-in-cell code, an advanced simulation model is established to study the sheath physics and dose uniformity along the sample stage in order to provide the theoretical basis for further improvement of enhanced glow discharge plasma immersion ion implantation and deposition. At t=7.0 mus, the expansion of the sheath in the horizontal direction is hindered by the dielectric cage. The electron focusing effect is demonstrated by this model. Most of the ions at the inside wall of the cage are implanted into the edge of the sample stage and a relatively uniform ion fluence distribution with a large peak is observed at the end. Compared to the results obtained from the previous model, a higher implant fluence and larger area of uniformity are disclosed.

  19. Contamination due to memory effects in filtered vacuum arc plasma deposition systems

    SciTech Connect

    Martins, D.R.; Salvadori, M.C.; Verdonck, P.; Brown, I.G.

    2002-08-13

    Thin film synthesis by filtered vacuum arc plasma deposition is a widely used technique with a number of important emerging technological applications. A characteristic feature of the method is that during the deposition process not only is the substrate coated by the plasma, but the plasma gun itself and the magnetic field coil and/or vacuum vessel section constituting the macroparticle filter are also coated to some extent. If then the plasma gun cathode is changed to a new element, there can be a contamination of the subsequent film deposition by sputtering from various parts of the system of the previous coating species. We have experimentally explored this effect and compared our results with theoretical estimates of sputtering from the SRIM (Stopping and Range of Ions in Matter) code. We find film contamination of order 10-4 - 10-3, and the memory of the prior history of the deposition hardware can be relatively long-lasting.

  20. Ultrafast thermal plasma physical vapor deposition of yttria-stabilized zirconia for novel thermal barrier coatings

    NASA Astrophysics Data System (ADS)

    Huang, Heji; Eguchi, Keisuke; Kambara, Makoto; Yoshida, Toyonobu

    2006-03-01

    This research aims to develop advanced thermal plasma spraying technology for the next-generation thermal barrier coatings (TBCs) with a high power hybrid plasma spraying system. By using thermal plasma physical vapor deposition (TP-PVD), various functional structured yttria-stabilized zirconia (YSZ) coatings were deposited. Parameters, such as powder feeding rate, hydrogen gas concentration, and total mass flow rate of the plasma gas, were optimized, and their influences on the evaporation of YSZ powder were investigated. Ultrafast deposition of a thick coating was achieved at a rate of over 150 μm/min. The deposited porous coating has a low thermal conductivity of 0.7W/mK and the dense coating with interlaced t' domains possesses a high nanohardness of 27.85 GPa and a high reflectance. These characteristics show that the TP-PVD technique is a very valuable process for manufacturing novel TBCs.

  1. Process Conditions and Microstructures of Ceramic Coatings by Gas Phase Deposition Based on Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Mauer, G.; Hospach, A.; Zotov, N.; Vaßen, R.

    2013-03-01

    Plasma spraying at very low pressure (50-200 Pa) is significantly different from atmospheric plasma conditions (APS). By applying powder feedstock, it is possible to fragment the particles into very small clusters or even to evaporate the material. As a consequence, the deposition mechanisms and the resulting coating microstructures could be quite different compared to conventional APS liquid splat deposition. Thin and dense ceramic coatings as well as columnar-structured strain-tolerant coatings with low thermal conductivity can be achieved offering new possibilities for application in energy systems. To exploit the potential of such a gas phase deposition from plasma spray-based processes, the deposition mechanisms and their dependency on process conditions must be better understood. Thus, plasma conditions were investigated by optical emission spectroscopy. Coating experiments were performed, partially at extreme conditions. Based on the observed microstructures, a phenomenological model is developed to identify basic growth mechanisms.

  2. Low-pressure microwave plasma nucleation and deposition of diamond films

    NASA Technical Reports Server (NTRS)

    Shing, Y. H.; Pool, F. S.; Rich, D. H.

    1992-01-01

    Low-pressure microwave plasma nucleation and deposition of diamond films were investigated in the pressure range 10-mtorr to 10 torr, at substrate temperatures 400-750 C and with CH4 and O2 concentrations in H2 plasma of 2-15 percent and 2-10 percent, respectively. The experiments were performed in a microwave plasma system consisting of a microwave plasma chamber, a downstream deposition chamber, and an RF induction heated sample stage. Scanning electron microscopy of diamond films deposited at 600 C with 5 percent CH4 and 5 percent O2 in H2 plasmas showed high-quality well faceted crystallites of 1/2 micron size. Cathodoluminescence measurements of these films showed very few nitrogen impurities and no detectable silicon impurities.

  3. The Role of Plasma in Plasma Enhanced Chemical Vapour Deposition of Nanostructure Growth

    NASA Technical Reports Server (NTRS)

    Hash, David B.; Meyyappan, M.; Teo, Kenneth B. K.; Lacerda, Rodrigo G.; Rupesinghe, Nalin L.

    2004-01-01

    Chemical vapour deposition (CVD) has become the preferred process for high yield growth of carbon nanotubes and nanofibres because of its ability to pattern growth through lithographic positioning of transition metal catalysts on substrates. Many potential applications of nanotubes such as field emitters [1] require not only patterned growth but also vertical alignment. Some degree of ali,ment in thermal CVD processes can be obtained when carbon nanotubes are grown closely together as a result of van der Waals interactions. The ali,onment however is marginal, and the van der Waals prerequisite makes growth of freestanding nanofibres with thermal CVD unrealizable. The application of electric fields as a means of ali,onment has been shown to overcome this limitation [2-5], and highly aligned nanostructures can be grown if electric fields on the order of 0.5 V/microns are employed. Plasma enhanced CVD in various configurations including dc, rf, microwave, inductive and electron cyclotron resonance has been pursued as a means of enabling alignment in the CVD process. However, the sheath fields for the non-dc sources are in general not sufficient for a high degree of ali,pment and an additional dc bias is usually applied to the growth substrate. This begs the question as to the actual role of the plasma. It is clear that the plasma itself is not required for aligned growth as references [3] and [4] employed fields through small applied voltages (3-20 V) across very small electrode spacings (10-100 microns) and thus avoided striking a discharge.

  4. Electrowetting on plasma-deposited fluorocarbon hydrophobic films for biofluid transport in microfluidics

    SciTech Connect

    Bayiati, P.; Tserepi, A.; Petrou, P. S.; Kakabakos, S. E.; Misiakos, K.; Gogolides, E.

    2007-05-15

    The present work focuses on the plasma deposition of fluorocarbon (FC) films on surfaces and the electrostatic control of their wettability (electrowetting). Such films can be employed for actuation of fluid transport in microfluidic devices, when deposited over patterned electrodes. Here, the deposition was performed using C{sub 4}F{sub 8} and the plasma parameters that permit the creation of films with optimized properties desirable for electrowetting were established. The wettability of the plasma-deposited surfaces was characterized by means of contact angle measurements (in the static and dynamic mode). The thickness of the deposited films was probed in situ by means of spectroscopic ellipsometry, while the surface roughness was provided by atomic force microscopy. These plasma-deposited FC films in combination with silicon nitride, a material of high dielectric constant, were used to create a dielectric structure that requires reduced voltages for successful electrowetting. Electrowetting experiments using protein solutions were conducted on such optimized dielectric structures and were compared with similar structures bearing commercial spin-coated Teflon registered amorphous fluoropolymer (AF) film as the hydrophobic top layer. Our results show that plasma-deposited FC films have desirable electrowetting behavior and minimal protein adsorption, a requirement for successful transport of biological solutions in 'digital' microfluidics.

  5. Study on effect of plasma surface treatments for diamond deposition by DC arc plasmatron.

    PubMed

    Kang, In-Je; Joa, Sang-Beom; Lee, Heon-Ju

    2013-11-01

    To improve the thermal conductivity and wear resistance of ceramic materials in the field of renewable energy technologies, diamond coating by plasma processing has been carried out in recent years. This study's goal is to improve diamond deposition on Al2O3 ceramic substrates by plasma surface treatments. Before diamond deposition was carried out in a vacuum, plasma surface treatments using Ar gas were conducted to improve conditions for deposition. We also conducted plasma processing for diamond deposition on Al2O3 ceramic substrates using a DC arc Plasmatron. The Al2O3 ceramic substrates with diamond film (5 x 15 mm2), were investigated by SEM (Scanning Electron Microscopy), AFM (Atomic Force Microscopy) and XRD (X-ray Diffractometer). Then, the C-H stretching of synthetic diamond films by FTIR (Fourier Transform Infrared Spectroscopy) was studied. We identified nanocrystalline diamond films on the Al2O3 ceramic substrates. The results showed us that the deposition rate of diamond films was 2.3 microm/h after plasma surface treatments. Comparing the above result with untreated ceramic substrates, the deposition rate improved with the surface roughness of the deposited diamond films. PMID:24245257

  6. Method For Plasma Source Ion Implantation And Deposition For Cylindrical Surfaces

    DOEpatents

    Fetherston, Robert P. , Shamim, Muhammad M. , Conrad, John R.

    1997-12-02

    Uniform ion implantation and deposition onto cylindrical surfaces is achieved by placing a cylindrical electrode in coaxial and conformal relation to the target surface. For implantation and deposition of an inner bore surface the electrode is placed inside the target. For implantation and deposition on an outer cylindrical surface the electrode is placed around the outside of the target. A plasma is generated between the electrode and the target cylindrical surface. Applying a pulse of high voltage to the target causes ions from the plasma to be driven onto the cylindrical target surface. The plasma contained in the space between the target and the electrode is uniform, resulting in a uniform implantation or deposition of the target surface. Since the plasma is largely contained in the space between the target and the electrode, contamination of the vacuum chamber enclosing the target and electrodes by inadvertent ion deposition is reduced. The coaxial alignment of the target and the electrode may be employed for the ion assisted deposition of sputtered metals onto the target, resulting in a uniform coating of the cylindrical target surface by the sputtered material. The independently generated and contained plasmas associated with each cylindrical target/electrode pair allows for effective batch processing of multiple cylindrical targets within a single vacuum chamber, resulting in both uniform implantation or deposition, and reduced contamination of one target by adjacent target/electrode pairs.

  7. High power impulse magnetron sputtering and related discharges: scalable plasma sources for plasma-based ion implantation and deposition

    SciTech Connect

    Anders, Andre

    2009-09-01

    High power impulse magnetron sputtering (HIPIMS) and related self-sputtering techniques are reviewed from a viewpoint of plasma-based ion implantation and deposition (PBII&D). HIPIMS combines the classical, scalable sputtering technology with pulsed power, which is an elegant way of ionizing the sputtered atoms. Related approaches, such as sustained self-sputtering, are also considered. The resulting intense flux of ions to the substrate consists of a mixture of metal and gas ions when using a process gas, or of metal ions only when using `gasless? or pure self-sputtering. In many respects, processing with HIPIMS plasmas is similar to processing with filtered cathodic arc plasmas, though the former is easier to scale to large areas. Both ion implantation and etching (high bias voltage, without deposition) and thin film deposition (low bias, or bias of low duty cycle) have been demonstrated.

  8. Fabrication of Carbon Nanotubes by Slot-Excited Microwave Plasma-Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Shim, Gyu Il; Kojima, Yoshihiro; Kono, Satoshi; Ohno, Yutaka; Ishijima, Tatsuo

    2008-07-01

    Carbon nanotubes (CNTs) are fabricated by adopting plasma-enhanced chemical vapor deposition (PECVD) with a planar microwave plasma source. Plasma is produced by a slot antenna at 2.45-GHz microwave injection in CH4/H2 mixture. In this study, it is shown that avoiding the exposure of the substrate to the plasma drastically improves the CNT growth. Furthermore, it is found that the CNT quality can be controlled with the optimization of one of the steps in the catalyst treatment, such as the preheating procedure; the treated catalyst is considered to be unaffected by the heating in the high-density microwave plasma treatment during the CNT growth.

  9. Plasma-enhanced atomic layer deposition: a gas-phase route to hydrophilic, glueable polytetrafluoroethylene.

    PubMed

    Roy, Amit K; Dendooven, Jolien; Deduytsche, Davy; Devloo-Casier, Kilian; Ragaert, Kim; Cardon, Ludwig; Detavernier, Christophe

    2015-02-28

    This communication reports an approach based on plasma-enhanced atomic layer deposition of aluminium oxide for the functionalization of polytetrafluoroethylene (PTFE or "Teflon") surfaces. Alternating exposure of PTFE to oxygen plasma and trimethylaluminium causes a permanent hydrophilic effect, and a more than 10-fold improvement of the "glueability" of PTFE to aluminium. PMID:25631168

  10. Plasma-enhanced atomic layer deposition of silicon dioxide films using plasma-activated triisopropylsilane as a precursor

    SciTech Connect

    Jeon, Ki-Moon; Shin, Jae-Su; Yun, Ju-Young; Jun Lee, Sang; Kang, Sang-Woo

    2014-05-15

    The plasma-enhanced atomic layer deposition (PEALD) process was developed as a growth technique of SiO{sub 2} thin films using a plasma-activated triisopropylsilane [TIPS, ((iPr){sub 3}SiH)] precursor. TIPS was activated by an argon plasma at the precursor injection stage of the process. Using the activated TIPS, it was possible to control the growth rate per cycle of the deposited films by adjusting the plasma ignition time. The PEALD technique allowed deposition of SiO{sub 2} films at temperatures as low as 50 °C without carbon impurities. In addition, films obtained with plasma ignition times of 3 s and 10 s had similar values of root-mean-square surface roughness. In order to evaluate the suitability of TIPS as a precursor for low-temperature deposition of SiO{sub 2} films, the vapor pressure of TIPS was measured. The thermal stability and the reactivity of the gas-phase TIPS with respect to water vapor were also investigated by analyzing the intensity changes of the C–H and Si–H peaks in the Fourier-transform infrared spectrum of TIPS.

  11. Influence of the normalized ion flux on the constitution of alumina films deposited by plasma-assisted chemical vapor deposition

    SciTech Connect

    Kurapov, Denis; Reiss, Jennifer; Trinh, David H.; Hultman, Lars; Schneider, Jochen M.

    2007-07-15

    Alumina thin films were deposited onto tempered hot working steel substrates from an AlCl{sub 3}-O{sub 2}-Ar-H{sub 2} gas mixture by plasma-assisted chemical vapor deposition. The normalized ion flux was varied during deposition through changes in precursor content while keeping the cathode voltage and the total pressure constant. As the precursor content in the total gas mixture was increased from 0.8% to 5.8%, the deposition rate increased 12-fold, while the normalized ion flux decreased by approximately 90%. The constitution, morphology, impurity incorporation, and the elastic properties of the alumina thin films were found to depend on the normalized ion flux. These changes in structure, composition, and properties induced by normalized ion flux may be understood by considering mechanisms related to surface and bulk diffusion.

  12. Plasma-deposited amorphous hydrogenated carbon films and their tribological properties

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Pouch, J. J.; Alterovitz, S. A.

    1989-01-01

    Recent work on the properties of diamondlike carbon films and their dependence on preparation conditions are reviewed. The results of the study indicate that plasma deposition enables one to deposit a variety of amorphous hydrogenated carbon (a-C:H) films exhibiting more diamondlike behavior to more graphitic behavior. The plasma-deposited a-C:H can be effectively used as hard, wear-resistant, and protective lubricating films on ceramic materials such as Si(sub 3)N(sub 4) under a variety of environmental conditions such as moist air, dry nitrogen, and vacuum.

  13. Plasma-deposited amorphous hydrogenated carbon films and their tribological properties

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Pouch, John J.; Alterovitz, Samuel A.

    1989-01-01

    Recent work on the properties of diamondlike carbon films and their dependence on preparation conditions are reviewed. The results of the study indicate that plasma deposition enables one to deposit a variety of amorphous hydrogenated carbon (a-C:H ) films exhibiting more diamondlike behavior to more graphitic behavior. The plasma-deposited a-C:H can be effectively used as hard, wear-resistant, and protective lubricating films on ceramic materials such as Si(sub 3)N(sub 4) under a variety of environmental conditions such as moist air, dry nitrogrn, and vacuum.

  14. Study on re-sputtering during CNx film deposition through spectroscopic diagnostics of plasma

    NASA Astrophysics Data System (ADS)

    Liang, Peipei; Yang, Xu; Li, Hui; Cai, Hua; Sun, Jian; Xu, Ning; Wu, Jiada

    2015-10-01

    A nitrogen-carbon plasma was generated during the deposition of carbon nitride (CNx) thin films by pulsed laser ablation of a graphite target in a discharge nitrogen plasma, and the optical emission of the generated nitrogen-carbon plasma was measured for the diagnostics of the plasma and the characterization of the process of CNx film deposition. The nitrogen-carbon plasma was recognized to contain various species including nitrogen molecules and molecular ions excited in the ambient N2 gas, carbon atoms and atomic ions ablated from the graphite target and CN radicals. The temporal evolution and spatial distribution of the CN emission and their dependence on the substrate bias voltage show two groups of CN radicals flying in opposite directions. One represents the CN radicals formed as the products of the reactions occurring in the nitrogen-carbon plasma, revealing the reactive deposition of CNx film due to the reactive expansion of the ablation carbon plasma in the discharge nitrogen plasma and the effective formation of gaseous CN radicals as precursors for CNx film growth. The other one represents the CN radicals re-sputtered from the growing CNx film by energetic plasma species, evidencing the re-sputtering of the growing film accompanying film growth. And, the re-sputtering presents ion-induced sputtering features.

  15. Deposition Of Materials Using A Simple Planar Coil Radio Frequency Inductively Coupled Plasma System

    SciTech Connect

    Ng, K. H.; Wong, C. S.; Yap, S. L.; Gan, S. N.

    2009-07-07

    A planar coil RF inductively coupled plasma (PC-RFICP) systems is set up for the purpose of thin film deposition. The system is powered by a 13.56 MHz, 550 W, 50 OMEGA RF generator. The RF power is transferred to the plasma via a planar induction coil. The impedance matching unit consists of an air core step-down transformer and a tunable vacuum capacitor. This system is used for the plasma enhanced chemical vapor deposition (PECVD) of diamond-like carbon (DLC) film on silicon substrate, and hydrogenated amorphous carbon (a-C:H) film.

  16. Compositional study of silicon oxynitride thin films deposited using electron cyclotron resonance plasma-enhanced chemical vapor deposition technique

    SciTech Connect

    Baumann, H.; Sah, R.E.

    2005-05-01

    We have used backscattering spectrometry and {sup 15}N({sup 1}H,{alpha},{gamma}){sup 12}C nuclear reaction analysis techniques to study in detail the variation in the composition of silicon oxynitride films with deposition parameters. The films were deposited using 2.45 GHz electron cyclotron resonance plasma-enhanced chemical vapor deposition (PECVD) technique from mixtures of precursors argon, nitrous oxide, and silane at deposition temperature 90 deg. C. The deposition pressure and nitrous oxide-to-silane gas flow rates ratio have been found to have a pronounced influence on the composition of the films. When the deposition pressure was varied for a given nitrous oxide-to-silane gas flow ratio, the amount of silicon and nitrogen increased with the deposition pressure, while the amount of oxygen decreased. For a given deposition pressure, the amount of incorporated nitrogen and hydrogen decreased while that of oxygen increased with increasing nitrous oxide-to-silane gas flow rates ratio. For nitrous oxide-to-silane gas flow ratio of 5, we obtained films which contained neither chemically bonded nor nonbonded nitrogen atoms as revealed by the results of infrared spectroscopy, backscattering spectrometry, and nuclear reaction analysis. Our results demonstrate the nitrogen-free nearly stoichiometric silicon dioxide films can be prepared from a mixture of precursors argon, nitrous oxide, and silane at low substrate temperature using high-density PECVD technique. This avoids the use of a hazardous and an often forbidden pair of silane and oxygen gases in a plasma reactor.

  17. Control of interface nanoscale structure created by plasma-enhanced chemical vapor deposition.

    PubMed

    Peri, Someswara R; Akgun, Bulent; Satija, Sushil K; Jiang, Hao; Enlow, Jesse; Bunning, Timothy J; Foster, Mark D

    2011-09-01

    Tailoring the structure of films deposited by plasma-enhanced chemical vapor deposition (PECVD) to specific applications requires a depth-resolved understanding of how the interface structures in such films are impacted by variations in deposition parameters such as feed position and plasma power. Analysis of complementary X-ray and neutron reflectivity (XR, NR) data provide a rich picture of changes in structure with feed position and plasma power, with those changes resolved on the nanoscale. For plasma-polymerized octafluorocyclobutane (PP-OFCB) films, a region of distinct chemical composition and lower cross-link density is found at the substrate interface for the range of processing conditions studied and a surface layer of lower cross-link density also appears when plasma power exceeds 40 W. Varying the distance of the feed from the plasma impacts the degree of cross-linking in the film center, thickness of the surface layer, and thickness of the transition region at the substrate. Deposition at the highest power, 65 W, both enhances cross-linking and creates loose fragments with fluorine content higher than the average. The thickness of the low cross-link density region at the air interface plays an important role in determining the width of the interface built with a layer subsequently deposited atop the first. PMID:21875044

  18. Local deposition of SiOx plasma polymer films by a miniaturized atmospheric pressure plasma jet (APPJ)

    NASA Astrophysics Data System (ADS)

    Schäfer, J.; Foest, R.; Quade, A.; Ohl, A.; Weltmann, K.-D.

    2008-10-01

    An atmospheric plasma jet (APPJ, 27.17 MHz, Ar with 1% HMDSO) has been studied for the deposition of thin silicon-organic films. Jet geometries are attractive for local surface treatment or for conformal covering of 3D forms, e.g. inner walls of wells, trenches or cavities, because they are not confined by electrodes and their dimensions can be varied from several centimetres down to the sub-millimetre region. Deposition experiments have been performed on flat polymer and glass samples with a deposition rate of 0.25-23 nm s-1. The knowledge of the static deposition profile of the plasma source (footprint) is essential to allow for a controlled deposition with the source moving relative to the substrate. By adjusting the plasma parameters (RF power and gas flow) to the geometry (i.e. electrode configuration, tube diameter, relative tube position, substrate distance) the footprint can be shaped from a ring form reflecting the tube dimension to a parabolic profile. Next to the conventional stochastic mode of operation we observe a characteristic locked mode—reported here for the first time for an RF-APPJ which can improve the film deposition process distinctively. The experimental results of the local film distribution agree well with an analytical model of the deposition kinetics. The film properties have been evaluated (profilometry, XPS, FT-IR spectroscopy and SEM) for different deposition conditions and substrate distance. The FT-IR spectra demonstrate dominating SiO absorption bands, thus providing an indication for the prevailing (inorganic) SiOx character of the films. HMDSO molecules disintegrate to a sufficient degree as proved by the absence of CH2 absorption in the spectra. XPS measurements confirm the local dependence with a slightly increased organic character a few millimetres away from the maximum in the deposition profile. The substrate distance and the source direction both seem relevant and require consideration during coating of 3D objects.

  19. Niobium thin film coating on a 500-MHz copper cavity by plasma deposition

    SciTech Connect

    Haipeng Wang; Genfa Wu; H. Phillips; Robert Rimmer; Anne-Marie Valente; Andy Wu

    2005-05-16

    A system using an Electron Cyclotron Resonance (ECR) plasma source for the deposition of a thin niobium film inside a copper cavity for superconducting accelerator applications has been designed and is being constructed. The system uses a 500-MHz copper cavity as both substrate and vacuum chamber. The ECR plasma will be created to produce direct niobium ion deposition. The central cylindrical grid is DC biased to control the deposition energy. This paper describes the design of several subcomponents including the vacuum chamber, RF supply, biasing grid and magnet coils. Operational parameters are compared between an operating sample deposition system and this system. Engineering work progress toward the first plasma creation will be reported here.

  20. Deposition of Hard Chrome Coating onto Heat Susceptible Substrates by Low Power Microwave Plasma Spray

    NASA Astrophysics Data System (ADS)

    Redza, Ahmad; Yasui, Toshiaki; Fukumoto, Masahiro

    2016-02-01

    Microwave plasma spray requires relatively low power, which is lower than 1 kW in comparison to other plasma spraying method. Until now, we are able to deposit Cu and Hydroxyapatite coating onto heat susceptible substrate, CFRP which are difficult for conventional plasma spray due to the excessive heat input. In this paper, a hard chromium coating was deposited onto SUS304 and CFRP by a low power microwave plasma spray technique. By controlling the working gas flow rate and spraying distance, a hard chrome coating with thickness of approximately 30 μm was successfully deposited onto CFRP substrate with hardness of 1110 Hv0.05. Furthermore, the coating produced here is higher than that produced by hard chrome plating.

  1. Studies of Discharge Parameters Influence on the IPD Plasma Deposition Process

    NASA Astrophysics Data System (ADS)

    Rabiński, Marek; Zdunek, Krzysztof

    2006-01-01

    The paper presents recent studies of a current sheet dynamics influence on the surface engineering process of impulse plasma deposition (IPD). During the IPD process plasma is generated in the working gas due to a high-voltage high-current oscillating pulse discharge, ignited within an interelectrode region of a coaxial accelerator. The changes of plasma dynamics and generation mechanisms, e.g. the electric arc instead of the plasma sheet formation during the consecutive half-periods of discharge, cause the different deposition efficiency for accelerator with the outer electrode system composed of stainless steel rods instead of standard tubular one. The coating efficiency and deposited layer quality have been examined for the titanium nitride as the model material for surface engineering.

  2. The effect of bias voltage on the morphology and wettability of plasma deposited titanium oxide films

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Li, Yan; Guo, Kai; Zhang, Jing

    2008-02-01

    Hydrophobic and hydrophilic films with titanium oxide inside were grown by radio frequency plasma enhanced chemical vapor deposition (RF--PECVD) on glass substrates. Bias voltage was used as an assistant for the deposition process. And a comparison was made between with and without the bias voltage. Titanium tetraisopropoxide (TTIP-Ti (OC 3H 7) 4) was used as the precursor compound. Film wettability was tested by water contact angle measurement (CAM). The water contact angle (WAC) of the film deposited in plasma without biased voltage was greater than 145°, while the WAC of the film deposited in plasma with biased voltage was less than 30°. The morphology of the deposited films was observed by scanning electron microscope (SEM). It is found that the films grown without bias voltage were covered with lots of nano grain and pores, but the surface of the films deposition with bias voltage was much dense. The chemical structure and property of the deposited films were analyzed by Fourier-transformed infrared spectroscopy (FTIR), while the plasma phase was investigated by optical emission spectroscopy (OES).

  3. Optical emission studies of reactive species in plasma deposition

    SciTech Connect

    Kampas, F.J.; Griffith, R.W.

    1981-01-01

    Optical emission studies of the glow-discharge deposition of a-Si:H alloys reveal the presence of reactive species derived from process gases and impurities. Studies of the dependences of emission intensities upon deposition parameters elucidate the mechanisms of formation of these species. Effects of impurities detected by emission spectroscopy upon a-Si:H film electronic properties are discussed. A model of the chemical reactions involved in film growth is presented.

  4. Plasma deposition of thin film multilayers for surface engineering

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, R.; Kumar, Sushil

    2012-06-01

    Plasma surface Engineering for enhancing optical and tribological behaviour of a surface is discussed. Specifically, it is shown how optimized PECVD processing can produce sophisticated Rugate filters and AR coatings on plastic lenses. It is found that multilayer Diamond Like Carbon coatings (DLC), in a functionally graded geometry, obtained by a combination of plasma intensive processing, not only can impart high value of hardness to a surface but also wear protection at high contact loads.

  5. Modelling of plasma generation and thin film deposition by a non-thermal plasma jet at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Sigeneger, F.; Becker, M. M.; Foest, R.; Loffhagen, D.

    2016-09-01

    The gas flow and plasma in a miniaturized non-thermal atmospheric pressure plasma jet for plasma enhanced chemical vapour deposition has been investigated by means of hydrodynamic modelling. The investigation focuses on the interplay between the plasma generation in the active zone where the power is supplied by an rf voltage to the filaments, the transport of active plasma particles due to the gas flow into the effluent, their reactions with the thin film precursor molecules and the transport of precursor fragments towards the substrate. The main features of the spatially two-dimensional model used are given. The results of the numerical modelling show that most active particles of the argon plasma are mainly confined within the active volume in the outer capillary of the plasma jet, with the exception of molecular argon ions which are transported remarkably into the effluent together with slow electrons. A simplified model of the precursor kinetics yields radial profiles of precursor fragment fluxes onto the substrate, which agree qualitatively with the measured profiles of thin films obtained by static film deposition experiments.

  6. Reactive sputter-deposition of AlN films by dense plasma focus

    SciTech Connect

    Sadiq, Mehboob; Ahmad, S.; Shafiq, M.; Zakaullah, M.; Ahmad, R.; Waheed, A.

    2006-11-15

    A low energy (1.45 kJ) dense plasma focus device is used to deposit thin films of aluminum nitride (AlN) at room temperature on silicon substrates. For deposition of films, a conventional hollow copper anode is replaced with a solid aluminum anode and nitrogen is used as fill gas. The films are deposited using a multiple number of focus shots by placing the substrate in front of the anode. The deposited films are characterized using x-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, and a microhardness test. The XRD analysis of the films shows that the deposited films show strong c-axis alignment. The Raman spectra of the films indicate that the deposited films are under compressive stress and crystalline quality decreases with increasing number of focus shots. The microhardness results point toward the uniform deposition of hard AlN layers on silicon substrates.

  7. Deuterium and helium release and microstructure of tungsten deposition layers formed by RF plasma sputtering

    SciTech Connect

    Katayama, K.; Imaoka, K.; Tokitani, M.; Miyamoto, M.; Nishikawa, M.; Fukada, S.; Yoshida, N.

    2008-07-15

    It is important to evaluate tritium behavior in tungsten deposition layers considering a long-term plasma operation. In this study, tungsten deposition layers were formed by deuterium or helium RF plasma sputtering. The release behavior of deuterium or helium from the layers were observed by a thermal desorption method. When a tungsten deposition layer does not contain oxygen, the retained deuterium is mainly released as D{sub 2}. When oxygen exists in the layer, the majority of deuterium is released as water vapor. Tungsten deposition layers have an amorphous structure and consist offline grain with size of 2-3 nm. Numerous bubbles are observed in the layers. A formation of tungsten deposition layer in a fusion reactor may make tritium control more difficult. (authors)

  8. In situ mechanical spectroscopy of laser deposited films using plasma plume excited reed

    SciTech Connect

    Scharf, Thorsten; Krebs, Hans-Ulrich

    2006-09-15

    We show a new approach to in situ measure the mechanical properties of pulsed laser deposited thin films by plasma plume excited reed with high accuracy. A vibrating reed, consisting of a Si substrate, is mounted into a pulsed laser deposition chamber. After deposition of the polymer film for investigation, the Si substrate is excited by the energy of the expanding laser plasma coming from a Ag target. The oscillations of the reed and their damping are measured using a diode laser reflected at the back side of the substrate, by observing the reflections with a position sensitive detector. Data collection as well as the coordination with the deposition setup are done computer controlled. Temperature dependent measurements of the damping of the reed oscillations then allow us to perform mechanical spectroscopy investigations of laser deposited polymer films.

  9. Properties of silicon dioxide films deposited at low temperatures by microwave plasma enhanced decomposition of tetraethylorthosilicate

    SciTech Connect

    Ray, S.K.; Maiti, C.K.; Lahiri, S.K.; Chakrabarti, N.B.

    1992-05-01

    Silicon dioxide films have been deposited at low temperatures (200-250{degrees}C) by microwave plasma enhanced decomposition of tetraethylorthosilicate (TEOS). The effects of the presence of oxygen in the discharge in film deposition rate, mechanism, and the physical properties of the films have been investigated. Structural characterization of the deposited films has been carried out by etch rate measurements, infrared transmission spectra, x-ray photoelectron spectroscopy, Auger, and secondary ion mass spectrometry analyses. Films deposited using TEOS and oxygen have confirmed a density comparable to standard silane-based low-pressure chemical vapor deposited and plasma enhanced chemical vapor deposited oxides, nearly perfect stoichiometry, extremely low sodium and carbon content, and the absence of many undesirable hydrogen related bonds. Various electrical properties, viz., resistivity, breakdown strength, fixed oxide charge density, interface state density, and trapping behavior have been evaluated by the characterization of metal-oxide-semiconductor capacitors fabricated using deposited oxides. Deposited films on thin native oxides grown by either in situ plasma oxidation or a low temperature thermal oxidation exhibited excellent electrical properties. 32 refs., 16 figs., 2 tabs.

  10. Angular emission of ions and mass deposition from femtosecond and nanosecond laser-produced plasmas

    SciTech Connect

    Verhoff, B.; Harilal, S. S.; Hassanein, A.

    2012-06-15

    We investigated the angular distribution of ions and atoms emanating from femto- and nanosecond laser-produced metal plasmas under similar laser fluence conditions. For producing plasmas, aluminum targets are ablated in vacuum employing pulses from a Ti:Sapphire ultrafast laser (40 fs, 800 nm) and an Nd:YAG laser (6 ns, 1064 nm). The angular distribution of ion emission as well as the kinetic energy distribution is characterized by a Faraday cup, while a quartz microbalance is used for evaluating deposited mass. The ion and deposited mass features showed that fs laser ablated plasmas produced higher kinetic energy and more mass per pulse than ns plumes over all angles. The ion flux and kinetic energy studies show fs laser plasmas produce narrower angular distribution while ns laser plasmas provide narrower energy distribution.

  11. Plasma-Assisted Mist Chemical Vapor Deposition of Zinc Oxide Films for Flexible Electronics

    NASA Astrophysics Data System (ADS)

    Takenaka, Kosuke; Uchida, Giichiro; Setsuhara, Yuichi

    2015-09-01

    Plasma-assisted mist chemical vapor deposition of ZnO films was performed for transparent conductive oxide formation of flexible electronics. In this study, ZnO films deposition using atmospheric-pressure He plasma generated by a micro-hollow cathode-type plasma source has been demonstrated. To obtain detail information according to generation of species in the plasma, the optical emission spectra of the atmospheric pressure He plasma with and without mist were measured. The result without mist shows considerable emissions of He lines, emissions attributed to the excitation and dissociation of air including N2 and O2 (N, O, and NO radials, and N2 molecule; N2 second positive band and first positive band), while the results with mist showed strong emissions attributed to the dissociation of H2O (OH and H radicals). The deposition of ZnO films was performed using atmospheric-pressure He plasma. The XRD patterns showed no crystallization of the ZnO films irradiated with pure He. On the other hand, the ZnO film crystallized with the irradiation with He/O2 mixture plasma. These results indicate that the atmospheric-pressure He/O2 mixture plasma has sufficient reactivity necessary for the crystallization of ZnO films at room temperature. This work was supported partly by The Grant-in-Aid for Scientific Research (KAKENHI) (Grant-in-Aid for Scientific Research(C)) from the Japan Society for the Promotion of Science (JSPS).

  12. Effects of plasma power on the growth of carbon nanotubes in the plasma enhanced chemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Abdi, Y.; Arzi, E.; Mohajerzadeh, S.

    2008-11-01

    Effects of plasma power on the growth of the multi-wall carbon nanotubes (CNTs) are reported. CNTs were grown on the silicon wafers by plasma enhanced chemical vapor deposition (PECVD) method using a mixture of acetylene and hydrogen at the temperature of 650°C. Plasma powers ranging from zero to 35W were applied on the samples and the effects of different magnitudes of the plasma power on the growth direction of the CNTs were investigated. Regular vertically aligned nanotubes were obtained at plasma power of 25W. In order to set on the plasma during the growth, electrical force was applied on the carbon ions. Nickel layer was used as a catalyst, and prior to the nanotubes growth step, it was treated by hydrogen plasma bombardment in order to obtain the Ni nano-islands. In this step, as the plasma power on the Ni layer was increased, the grain size of nickel nano-particles decreased, and hence, nanotubes of smaller diameter were obtained later on. At the last step some anomalous structures of agglomerated CNTs were obtained by controlling the plasma power. Samples were analyzed by scanning tunneling microscopy (STM) and scanning electron microscopy (SEM).

  13. ZnO thin film deposition using colliding plasma plumes and single plasma plume: Structural and optical properties

    SciTech Connect

    Gupta, Shyam L. Thareja, Raj K.

    2013-12-14

    We report the comparative study on synthesis of thin films of ZnO on glass substrates using IR laser ablated colliding plasma plumes and conventional pulsed laser deposition using 355 nm in oxygen ambient. The optical properties of deposited films are characterized using optical transmission in the UV-visible range of spectrum and photoluminescence measurements. X-ray diffraction and atomic force microscopy are used to investigate the surface morphology of synthesized ZnO films. The films synthesized using colliding plumes created with 1064 nm are non-polar a-plane ZnO with transmission in UV-visible (300–800 nm) region ∼60% compared to polycrystalline thin film deposited using single plume which has chunk deposition and poor optical response. However, deposition with 355 nm single plume shows polar c-axis oriented thin film with average roughness (∼thickness) of ∼86 nm (∼850 nm) compared to ∼2 nm (∼3 μm) for 1064 nm colliding plumes. These observed differences in the quality and properties of thin films are attributed to the flux of mono-energetic plasma species with almost uniform kinetic energy and higher thermal velocity reaching the substrate from interaction/stagnation zone of colliding plasma plumes.

  14. Latest innovations in large area web coating technology via plasma enhanced chemical vapor deposition source technology

    SciTech Connect

    George, M. A.; Chandra, H.; Morse, P.; Madocks, J.

    2009-07-15

    In this article, the authors discuss the latest results of our development of large area plasma enhanced chemical vapor deposition (PECVD) source technologies for flexible substrates. A significant challenge is the economical application of thin films for use as vapor barriers, transparent conductive oxides, and optical interference thin films. Here at General Plasma the authors have developed two innovative PECVD source technologies that provide an economical alternative to low temperature sputtering technologies and enable some thin film materials not accessible by sputtering. The Penning Discharge Plasma (PDP trade mark sign ) source is designed for high rate direct PECVD deposition on insulating, temperature sensitive web [J. Modocks, Proceedings of the Society of Vacuum Coaters, 2003 (unpublished), p. 187]. This technology has been utilized to deposit SiO{sub 2} and SiC:H for barrier applications [V. Shamamian et al. Proceedings of the Flexible Displays and Manufacturing Conferrence, 2006 (unpublished)]. The Plasma Beam Source (PBS trade mark sign ) is a remote plasma source that is more versatile for deposition on not only insulating flexible substrates but also conductive or rigid substrates for deposition of thin films that are sensitive to the high ion bombardment flux inherent to the PDP trade mark sign technology. The authors have developed PBS thin film processes in our laboratory for deposition of SiO{sub 2}, SiC:O, SiN:C, SiN:H, ZnO, FeO{sub x}, and Al{sub 2}O{sub 3}. [M. A. George, Conference Proceedings of the Association of Industrial Metallizers, Coaters, and Laminators (AIMCAL), 2007 (unpublished)]. The authors discuss the design of the patented sources, plasma physics, and chemistry of the deposited thin films.

  15. Silicon nitride films deposited with an electron beam created plasma

    NASA Astrophysics Data System (ADS)

    Bishop, D. C.; Emery, K. A.; Rocca, J. J.; Thompson, L. R.; Zamani, H.; Collins, G. J.

    1984-03-01

    The electron beam assisted chemical vapor deposition (EBCVD) of silicon nitride films using NH3, N2, and SiH4 as the reactant gases is reported. The films have been deposited on aluminum, SiO2, and polysilicon film substrates as well as on crystalline silicon substrates. The range of experimental conditions under which silicon nitrides have been deposited includes substrate temperatures from 50 to 400 C, electron beam currents of 2-40 mA, electron beam energies of 1-5 keV, total ambient pressures of 0.1-0.4 Torr, and NH3/SiH4 mass flow ratios of 1-80. The physical, electrical, and chemical properties of the EBCVD films are discussed.

  16. Mass spectrometric studies of SiO2 deposition in an indirect plasma enhanced LPCVD system

    NASA Technical Reports Server (NTRS)

    Iyer, R.; Lile, D. L.; Mcconica, C. M.

    1993-01-01

    Reaction pathways for the low temperature deposition of SiO2 from silane and indirect plasma-excited oxygen-nitrogen mixtures are proposed based on experimental evidence gained from mass spectrometry in an indirect plasma enhanced chemical vapor deposition chamber. It was observed that about 80-85 percent of the silane was oxidized to byproduct hydrogen and only about 15-20 percent to water. Such conversion levels have led us to interpret that silanol (SiH3OH) could be the precursor for SiO2 film deposition, rather than siloxane /(SiH3)2O/ which has generally been cited in the literature. From mass spectrometry, we have also shown the effects of the plasma, and of mixing small amounts of N2 with the oxygen flow, in increasing the deposition rate of SiO2. Free radical reaction of nitric oxide, synthesized from the reaction of oxygen and nitrogen in the plasma chamber, and an *ncrease in atomic oxygen concentration, are believed to be the reasons for these SiO2 deposition rate increases. Through mass spectrometry we have, in addition, been able to identify products, presumably originating from terminating reactions, among a sequence of chemical reactions proposed for the deposition of SiO2.

  17. Plasma Spray-Physical Vapor Deposition (PS-PVD) of Ceramics for Protective Coatings

    NASA Technical Reports Server (NTRS)

    Harder, Bryan J.; Zhu, Dongming

    2011-01-01

    In order to generate advanced multilayer thermal and environmental protection systems, a new deposition process is needed to bridge the gap between conventional plasma spray, which produces relatively thick coatings on the order of 125-250 microns, and conventional vapor phase processes such as electron beam physical vapor deposition (EB-PVD) which are limited by relatively slow deposition rates, high investment costs, and coating material vapor pressure requirements. The use of Plasma Spray - Physical Vapor Deposition (PS-PVD) processing fills this gap and allows thin (< 10 microns) single layers to be deposited and multilayer coatings of less than 100 microns to be generated with the flexibility to tailor microstructures by changing processing conditions. Coatings of yttria-stabilized zirconia (YSZ) were applied to NiCrAlY bond coated superalloy substrates using the PS-PVD coater at NASA Glenn Research Center. A design-of-experiments was used to examine the effects of process variables (Ar/He plasma gas ratio, the total plasma gas flow, and the torch current) on chamber pressure and torch power. Coating thickness, phase and microstructure were evaluated for each set of deposition conditions. Low chamber pressures and high power were shown to increase coating thickness and create columnar-like structures. Likewise, high chamber pressures and low power had lower growth rates, but resulted in flatter, more homogeneous layers

  18. Deposition of polymeric perfluored thin films in proton ionic membranes by plasma processes

    NASA Astrophysics Data System (ADS)

    Polak, Peter Lubomir; Mousinho, Ana Paula; Ordonez, Nelson; da Silva Zambom, Luis; Mansano, Ronaldo Domingues

    2007-10-01

    In this work the surfaces of polymeric membranes based on Nafion (proton conducting material), used in proton exchange membranes fuel cells (PEMFC) had been modified by plasma deposition of perfluored polymers, in order to improve its functioning in systems of energy generation (fuel cells). The deposition increases the chemical resistance of the proton ionic polymers without losing the electrical properties. The processing of the membranes also reduces the permeability of the membranes to the alcohols (methanol and ethanol), thus preventing poisoning of the fuel cell. The processing of the membranes of Nafion was carried through in a system of plasma deposition using a mixture of CF 4 and H 2 gases. The plasma processing was made mainly to increase the chemical resistance and result in hydrophobic surfaces. The Fourier transformed infrared (FTIR) technique supplies a spectrum with information about the CF n bond formation. Through the Rutherford back scattering (RBS) technique it was possible to verify the deposition rate of the polymeric layer. The plasma process with composition of 60% of CF 4 and 40% of H 2 presented the best deposition rate. By the spectrum analysis for the optimized configuration, it was possible to verify that the film deposition occurred with a thickness of 90 nm, and fluorine concentration was nearly 30%. Voltammetry made possible to verify that the fluorination increases the membranes chemical resistance, improving the stability of Nafion, becoming an attractive process for construction of fuel cells.

  19. Mechanical and piezoresistive properties of thin silicon films deposited by plasma-enhanced chemical vapor deposition and hot-wire chemical vapor deposition at low substrate temperatures

    NASA Astrophysics Data System (ADS)

    Gaspar, J.; Gualdino, A.; Lemke, B.; Paul, O.; Chu, V.; Conde, J. P.

    2012-07-01

    This paper reports on the mechanical and piezoresistance characterization of hydrogenated amorphous and nanocrystalline silicon thin films deposited by hot-wire chemical vapor deposition (HWCVD) and radio-frequency plasma-enhanced chemical vapor deposition (PECVD) using substrate temperatures between 100 and 250 °C. The microtensile technique is used to determine film properties such as Young's modulus, fracture strength and Weibull parameters, and linear and quadratic piezoresistance coefficients obtained at large applied stresses. The 95%-confidence interval for the elastic constant of the films characterized, 85.9 ± 0.3 GPa, does not depend significantly on the deposition method or on film structure. In contrast, mean fracture strength values range between 256 ± 8 MPa and 600 ± 32 MPa: nanocrystalline layers are slightly stronger than their amorphous counterparts and a pronounced increase in strength is observed for films deposited using HWCVD when compared to those grown by PECVD. Extracted Weibull moduli are below 10. In terms of piezoresistance, n-doped radio-frequency nanocrystalline silicon films deposited at 250 °C present longitudinal piezoresistive coefficients as large as -(2.57 ± 0.03) × 10-10 Pa-1 with marginally nonlinear response. Such values approach those of crystalline silicon and of polysilicon layers deposited at much higher temperatures.

  20. Interaction of platelets, fibrinogen and endothelial cells with plasma deposited PEO-like films

    NASA Astrophysics Data System (ADS)

    Yang, Zhilu; Wang, Jin; Li, Xin; Tu, Qiufen; Sun, Hong; Huang, Nan

    2012-02-01

    For blood-contacting biomedical implants like retrievable vena cava filters, surface-based diagnostic devices or in vivo sensors, limiting thrombosis and cell adhesion is paramount, due to a decrease even failure in performance. Plasma deposited PEO-like films were investigated as surface modifications. In this work, mixed gas composed of tetraethylene glycol dimethyl ether (tetraglyme) vapor and oxygen was used as precursor. It was revealed that plasma polymerization under high ratio of oxygen/tetraglyme led to deposition of the films that had high content of ether groups. This kind of PEO-like films had good stability in phosphate buffer solution. In vitro hemocompatibility and endothelial cell (EC) adhesion revealed low platelet adhesion, platelet activation, fibrinogen adhesion, EC adhesion and proliferation on such plasma deposited PEO-like films. This made it a potential candidate for the applications in anti-fouling surfaces of blood-contacting biomedical devices.

  1. Characterization of low dielectric constant plasma polymer films deposited by plasma-enhanced chemical vapor deposition using decamethyl-cyclopentasiloxane and cyclohexane as the precursors

    SciTech Connect

    Yang, Jaeyoung; Lee, Sungwoo; Park, Hyoungsun; Jung, Donggeun; Chae, Heeyeop

    2006-01-15

    We investigated the properties of plasma polymer films deposited by plasma-enhanced chemical vapor deposition using a mixture of decamethyl-cyclopentasiloxane (C{sub 10}H{sub 30}O{sub 5}Si{sub 5}) and cyclohexane (C{sub 6}H{sub 12}) as the precursors, which we refer to as plasma polymerized decamethyl-cyclopentasiloxane: cyclohexane (PPDMCPSO:CHex) films. The relative dielectric constants, k, of the plasma polymer films were correlated with the Fourier transform infrared absorption peaks of the C-Hx, Si-CH{sub 3}, and Si-O related groups. As the amount of the CHx species in the as-deposited plasma polymer films increased, the k value and the leakage current density of the thin films decreased. The subsequent annealing of the PPDMCPSO:CHex film at 400 deg. C for 1 h further reduced the k value to as low as k=2.05. This annealed PPDMCPSO:CHex thin film showed a leakage current density of the order of 4x10{sup -7} A/cm{sup 2} at 1 MV/cm and a breakdown field of 6.5 MV/cm. Through the bias-temperature stress test, it was estimated that the PPDMCPSO:CHex film with a k value of 2.05 would retain its insulating properties for ten years at 167 deg. C under an electrical field of 1 MV/cm, when it is presented as a layer adjacent to Cu/TaN(10 nm)

  2. Structural Evolution of SiC Films During Plasma-Assisted Chemical Vapour Deposition

    NASA Astrophysics Data System (ADS)

    Ding, Siye; Yan, Guanchao; Zhu, Xiaodong; Zhou, Haiyang

    2009-04-01

    Evolution of chemical bonding configurations for the films deposited from hexamethyldisiloxane (HMDSO) diluted with H2 during plasma assisted chemical vapour deposition is investigated. In the experiment a small amount of CH4 was added to adjust the plasma environment and modify the structure of the deposited films. The measurements of Raman spectroscopy and X-ray diffraction (XRD) revealed the production of 6H-SiC embedded in the amorphous matrix without the input of CH4. As CH4 was introduced into the deposition reaction, the transition of 6H-SiC to cubic SiC in the films took place, and also the film surfaces changed from a structure of ellipsoids to cauliflower-like shapes. With a further increase of CH4 in the flow ratio, the obtained films varied from Si-C bonding dominant to a sp2/sp3 carbon-rich composition.

  3. Plasma source ion implantation to increase the adhesion of subsequently deposited coatings

    SciTech Connect

    Wood, B.P.; Walter, K.C.; Taylor, T.N.

    1997-10-01

    In Plasma Source Ion Implantation (PSII) an object is placed in a plasma and pulse biased to a high negative potential, so as to implant the plasma ions into the surface of the object. Although ion implantation, by itself, can yield desirable surface modification, it is even more useful as a method of creating a functionally graded interface between the substrate material and a subsequently deposited coating, which may be produced by altering operating conditions on the same plasma source. Although this interfacial region is very thin - as little as 20 nm - it can greatly increase the adhesion of the deposited coatings. We present here a description of this process, and compare a simulation of the graded interface with an XPS depth profile of the interfacial region for erbium metal implanted into steel.

  4. Growing aluminum nitride films by Plasma-Enhanced Atomic Layer Deposition at low temperatures

    NASA Astrophysics Data System (ADS)

    Tarala, V. A.; Altakhov, A. S.; Martens, V. Ya; Lisitsyn, S. V.

    2015-11-01

    Aluminum nitride films have been grown by Plasma-Enhanced Atomic Layer Deposition method. It was found that at temperatures of 250 °C and 280 °C increase of the plasma exposure step duration over 6 s, as well as increase of reactor purge step duration over 1 s does not affect the growth rate, however, it affects the microstructure of the films. It was found that crystalline aluminum nitride films deposit with plasma exposure duration over 10 s and the reactor purging over 10 s. When the temperature drops the increase of reactor purge step duration and plasma exposure step duration over 20 s is required for crystalline AlN film growth.

  5. Characterisation of the TiO2 coatings deposited by plasma spraying

    NASA Astrophysics Data System (ADS)

    Benea, M. L.; Benea, L. P.

    2016-02-01

    Plasma spraying of materials such as ceramics and non-metals, which have high melting points, has become a well-established commercial process. Such coatings are increasingly used in aerospace, automobile, textile, medical, printing and electrical industries to impart proprieties such as corrosion resistance, thermal resistance, wear resistance, etc. One of the most important characteristics of thermal barrier coatings is the ability to undergo fast temperature changes without failing, the so called thermal shock resistance. The formation of residual stresses in plasma sprayed ceramic and metallic coatings is a very complex process. Several factors, such as substrate material, substrate thickness, physical properties of both the substrate and the coating material, deposition rate, relative velocity of the plasma torch, etc. determine the final residual stress state of the coating at room temperature. Our objective is to characterize the titanium oxide and aluminium oxide coatings deposited by plasma spraying in structural terms, the resistance to thermal shock and residual stresses.

  6. Deposition of Functional Coatings from an Acetylene-Containing Plasma at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Plevako, F. V.; Gorbatov, S. V.; Davidovich, P. A.; Prikhod‧ko, E. M.; Shushkov, S. V.; Krul‧, L. P.; Butovskaya, G. V.; Shakhno, O. V.; Gusakova, S. V.; Korolik, O. V.; Mazanik, A. V.

    2016-03-01

    Properties of thin coatings formed on polymer and glass substrates by plasma-enhanced chemical vapor deposition from a mixture of nitrogen with acetylene at atmospheric pressure were investigated. It was established that chemically stable transparent films with a mass ratio of fixed carbon and nitrogen C:N ~ 2:1 are formed on the surface of these substrates. When the deposition time was increased, arrays of dendrite-like structures were formed on the substrates.

  7. Plasma-induced surface modification of polydimethylsiloxane aimed at reducing salt and protein deposition.

    PubMed

    De Smet, Nele; Rymarczyk-Machal, Monika; Schacht, Etienne

    2011-01-01

    Polydimethylsiloxane (PDMS) is an elastomer that is widely used in construction and for biological and biomedical applications. The biocompatibility of PDMS was improved by different surface treatment methods, i.e., plasma treatment or a combination of plasma treatment with UV-irradiation or redox initiator, to minimize the effects of deposition of salts and proteins. In this work we used the vinyl monomers sulfobetaine and AMPS which have good biocompatible properties. PMID:21176391

  8. Microwave engineering of plasma-assisted CVD reactors for diamond deposition

    NASA Astrophysics Data System (ADS)

    Silva, F.; Hassouni, K.; Bonnin, X.; Gicquel, A.

    2009-09-01

    The unique properties of CVD diamond make it a compelling choice for high power electronics. In order to achieve industrial use of CVD diamond, one must simultaneously obtain an excellent control of the film purity, very low defect content and a sufficiently rapid growth rate. Currently, only microwave plasma-assisted chemical vapour deposition (MPACVD) processes making use of resonant cavity systems provide enough atomic hydrogen to satisfy these requirements. We show in this paper that the use of high microwave power density (MWPD) plasmas is necessary to promote atomic hydrogen concentrations that are high enough to ensure the deposition of high purity diamond films at large growth rates. Moreover, the deposition of homogeneous films on large surfaces calls for the production of plasma with appropriate shapes and large volumes. The production of such plasmas needs generating a fairly high electric field over extended regions and requires a careful design of the MW coupling system, especially the cavity. As far as MW coupling efficiency is concerned, the presence of a plasma load represents a mismatching perturbation to the cavity. This perturbation is especially important at high MWPD where the reflected fraction of the input power may be quite high. This mismatch can lead to a pronounced heating of the reactor walls. It must therefore be taken into account from the very beginning of the reactor design. This requires the implementation of plasma modelling tools coupled to detailed electromagnetic simulations. This is discussed in section 3. We also briefly discuss the operating principles of the main commercial plasma reactors before introducing the reactor design methodology we have developed. Modelling results for a new generation of reactors developed at LIMHP, working at very high power density, will be presented. Lastly, we show that scaling up this type of reactor to lower frequencies (915 MHz) can result in high density plasmas allowing for fast and

  9. Microwave engineering of plasma-assisted CVD reactors for diamond deposition.

    PubMed

    Silva, F; Hassouni, K; Bonnin, X; Gicquel, A

    2009-09-01

    The unique properties of CVD diamond make it a compelling choice for high power electronics. In order to achieve industrial use of CVD diamond, one must simultaneously obtain an excellent control of the film purity, very low defect content and a sufficiently rapid growth rate. Currently, only microwave plasma-assisted chemical vapour deposition (MPACVD) processes making use of resonant cavity systems provide enough atomic hydrogen to satisfy these requirements. We show in this paper that the use of high microwave power density (MWPD) plasmas is necessary to promote atomic hydrogen concentrations that are high enough to ensure the deposition of high purity diamond films at large growth rates. Moreover, the deposition of homogeneous films on large surfaces calls for the production of plasma with appropriate shapes and large volumes. The production of such plasmas needs generating a fairly high electric field over extended regions and requires a careful design of the MW coupling system, especially the cavity. As far as MW coupling efficiency is concerned, the presence of a plasma load represents a mismatching perturbation to the cavity. This perturbation is especially important at high MWPD where the reflected fraction of the input power may be quite high. This mismatch can lead to a pronounced heating of the reactor walls. It must therefore be taken into account from the very beginning of the reactor design. This requires the implementation of plasma modelling tools coupled to detailed electromagnetic simulations. This is discussed in section 3. We also briefly discuss the operating principles of the main commercial plasma reactors before introducing the reactor design methodology we have developed. Modelling results for a new generation of reactors developed at LIMHP, working at very high power density, will be presented. Lastly, we show that scaling up this type of reactor to lower frequencies (915 MHz) can result in high density plasmas allowing for fast and

  10. Silicon carbon alloy thin film depositions using electron cyclotron resonance microwave plasmas

    NASA Technical Reports Server (NTRS)

    Shing, Y. H.; Pool, F. S.

    1990-01-01

    Amorphous and microcrystalline silicon carbon films (a-SiC:H, micro-c-SiC:H) have been deposited using SiH4, CH4 and H2 mixed gas ECR (electron cyclotron resonance) plasmas. The optical bandgap of a-SiC:H films is not dependent on the hydrogen dilution in the ECR plasma. The deposition rate of a-SiC:H films is found to be strongly dependent on the ECR magnetic field and the hydrogen dilution. The hydrogen dilution effect on the deposition rate indicates that the etching in ECR hydrogen plasmas plays an important role in the deposition of a-SiC:H films. The optical constants n and k of ECR-deposited a-SiC:H films in the wavelength region of 0.4 to 1.0 micron are determined to be 2.03-1.90 and 0.04-0.00, respectively. The microstructures of ECR-deposited micro-c-SiC:H films are shown by X-ray diffraction and SEM (scanning electron microscopy) to be composed of 1000-A alpha-SiC microcrystallites and amorphous network structures.

  11. Scalability of plasma enhanced atomic layer deposited ruthenium films for interconnect applications

    SciTech Connect

    Swerts, J.; Armini, S.; Carbonell, L.; Delabie, A.; Franquet, A.; Mertens, S.; Popovici, M.; Schaekers, M.; Witters, T.; Toekei, Z.; Beyer, G.; Van Elshocht, S.; Gravey, V.; Cockburn, A.; Shah, K.; Aubuchon, J.

    2012-01-15

    Ru thin films were deposited by plasma enhanced atomic layer deposition using MethylCyclopentadienylPyrrolylRuthenium (MeCpPy)Ru and N{sub 2}/NH{sub 3} plasma. The growth characteristics have been studied on titanium nitride or tantalum nitride substrates of various thicknesses. On SiO{sub 2}, a large incubation period has been observed, which can be resolved by the use of a metal nitride layer of {approx} 0.8 nm. The growth characteristics of Ru layers deposited on ultra-thin metal nitride layers are similar to those on thick metal nitride substrates despite the fact that the metal nitride layers are not fully closed. Scaled Ru/metal nitride stacks were deposited in narrow lines down to 25 nm width. Thinning of the metal nitride does not impact the conformality of the Ru layer in the narrow lines. For the thinnest lines the Ru deposited on the side wall showed a more granular structure when compared to the bottom of the trench, which is attributed to the plasma directionality during the deposition process.

  12. Antibiofouling Properties of Plasma-Deposited Oxazoline-Based Thin Films.

    PubMed

    Cavallaro, Alex A; Macgregor-Ramiasa, Melanie N; Vasilev, Krasimir

    2016-03-01

    Infections caused by the bacterial colonization of medical devices are a substantial problem to patients and healthcare. Biopassive polyoxazoline coatings are attracting attention in the biomedical field as one of the potential solutions to this problem. Here, we present an original and swift way to produce plasma-deposited oxazoline-based films for antifouling applications. The films developed via the plasma deposition of 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline have tunable thickness and surface properties. Diverse film chemistries were achieved by tuning and optimizing the deposition conditions. Human-derived fibroblasts were used to confirm the biocompatibility of oxazoline derived coatings. The capacity of the coatings to resist biofilm attachment was studied as a function of deposition power and mode (i.e., continuous wave or pulsed) and precursor flow rates for both 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline. After careful tuning of the deposition parameters films having the capacity to resist biofilm formation by more than 90% were achieved. The substrate-independent and customizable properties of the new generation of plasma deposited oxazoline thin films developed in this work make them attractive candidates for the coating of medical devices and other applications where bacteria surface colonization and biofilm formation is an issue. PMID:26901823

  13. Deposition kinetics and characterization of stable ionomers from hexamethyldisiloxane and methacrylic acid by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Urstöger, Georg; Resel, Roland; Koller, Georg; Coclite, Anna Maria

    2016-04-01

    A novel ionomer of hexamethyldisiloxane and methacrylic acid was synthesized by plasma enhanced chemical vapor deposition (PECVD). The PECVD process, being solventless, allows mixing of monomers with very different solubilities, and for polymers formed at high deposition rates and with high structural stability (due to the high number of cross-links and covalent bonding to the substrate) to be obtained. A kinetic study over a large set of parameters was run with the aim of determining the optimal conditions for high stability and proton conductivity of the polymer layer. Copolymers with good stability over 6 months' time in air and water were obtained, as demonstrated by ellipsometry, X-Ray reflectivity, and FT-IR spectroscopy. Stable coatings showed also proton conductivity as high as 1.1 ± 0.1 mS cm-1. Chemical analysis showed that due to the high molecular weight of the chosen precursors, it was possible to keep the plasma energy-input-per-mass low. This allowed limited precursor fragmentation and the functional groups of both monomers to be retained during the plasma polymerization.

  14. Plasma-based ion implantation and deposition: A review of physics,technology, and applications

    SciTech Connect

    Pelletier, Jacques; Anders, Andre

    2005-05-16

    After pioneering work in the 1980s, plasma-based ion implantation (PBII) and plasma-based ion implantation and deposition (PBIID) can now be considered mature technologies for surface modification and thin film deposition. This review starts by looking at the historical development and recalling the basic ideas of PBII. Advantages and disadvantages are compared to conventional ion beam implantation and physical vapor deposition for PBII and PBIID, respectively, followed by a summary of the physics of sheath dynamics, plasma and pulse specifications, plasma diagnostics, and process modeling. The review moves on to technology considerations for plasma sources and process reactors. PBII surface modification and PBIID coatings are applied in a wide range of situations. They include the by-now traditional tribological applications of reducing wear and corrosion through the formation of hard, tough, smooth, low-friction and chemically inert phases and coatings, e.g. for engine components. PBII has become viable for the formation of shallow junctions and other applications in microelectronics. More recently, the rapidly growing field of biomaterial synthesis makes used of PBII&D to produce surgical implants, bio- and blood-compatible surfaces and coatings, etc. With limitations, also non-conducting materials such as plastic sheets can be treated. The major interest in PBII processing originates from its flexibility in ion energy (from a few eV up to about 100 keV), and the capability to efficiently treat, or deposit on, large areas, and (within limits) to process non-flat, three-dimensional workpieces, including forming and modifying metastable phases and nanostructures. We use the acronym PBII&D when referring to both implantation and deposition, while PBIID implies that deposition is part of the process.

  15. Plasma Diagnostics For The Investigation of Silane Based Glow Discharge Deposition Processes

    NASA Astrophysics Data System (ADS)

    Mataras, Dimitrios

    2001-10-01

    In this work is presented the study of microcrystalline silicon PECVD process through highly diluted silane in hydrogen discharges. The investigation is performed by applying different non intrusive plasma diagnostics (electrical, optical, mass spectrometric and laser interferometric measurements). Each of these measurements is related to different plasma sub-processes (gas physics, plasma chemistry and plasma surface interaction) and compose a complete set, proper for the investigation of the effect of external discharge parameters on the deposition processes. In the specific case these plasma diagnostics are applied for prospecting the optimal experimental conditions from the ic-Si:H deposition rate point of view. Namely, the main characteristics of the effect of frequency, discharge geometry, power consumption and total gas pressure on the deposition process are presented successively. Special attention is given to the study of the frequency effect (13.56 MHz 50 MHz) indicating that the correct way to compare results of different driving frequency discharges is by maintaining constant the total power dissipation in the discharge. The important role of frequency in the achievement of high deposition rates and on the optimization of all other parameters is underlined. Finally, the proper combination of experimental conditions that result from the optimal choice of each of the above-mentioned discharge parameters and lead to high microcrystalline silicon deposition rates (7.5 Å/sec) is presented. The increase of silane dissociation rate towards neutral radicals (frequency effect), the contribution of highly sticking to the surface radicals (discharge geometry optimum) and the controlled production of higher radicals through secondary gas phase reactions (total gas pressure), are presented as prerequisites for the achievement of high deposition rates.

  16. Effect of argon and hydrogen on deposition of silicon from tetrochlrosilane in cold plasmas

    NASA Technical Reports Server (NTRS)

    Manory, R. R.; d.

    1985-01-01

    The roles of Ar and H2 on the decomposition of SiCl4 in cold plasma were investigated by Langmuir probes and mass spectrometry. Decomposition of the reactant by Ar only has been found to be very slow. In presence of H2 in the plasma SiCl4 is decomposed by fast radical-molecule reactions which are further enhanced by Ar due to additional ion-molecule reactions in which more H radicals are produced. A model for the plasma-surface interactions during deposition of mu-Si in the Ar + H2 + SiCl4 system is presented.

  17. Energy deposition of heavy ions in the regime of strong beam-plasma correlations.

    PubMed

    Gericke, D O; Schlanges, M

    2003-03-01

    The energy loss of highly charged ions in dense plasmas is investigated. The applied model includes strong beam-plasma correlation via a quantum T-matrix treatment of the cross sections. Dynamic screening effects are modeled by using a Debye-like potential with a velocity dependent screening length that guarantees the known low and high beam velocity limits. It is shown that this phenomenological model is in good agreement with simulation data up to very high beam-plasma coupling. An analysis of the stopping process shows considerably longer ranges and a less localized energy deposition if strong coupling is treated properly. PMID:12689203

  18. Energy deposition in parallel-plate plasma accelerators. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Dicapua, M. S.

    1971-01-01

    To appraise the ratio of energy deposition into kinetic and thermal modes in plasma accelerators, a parallel-plate plasma accelerator has been operated in the quasi-steady mode with current pulses in the range of 10 to 100 kilo-amperes (kA), durations of the order of one millisecond, and argon mass flows up to 100 grams/sec. From photographic observations, spectroscopic measurements of velocity and electron density, and pressure measurements with a fast-rise piezoelectric transducer it is found that, for currents between 50 and 90 kA, the accelerated argon plasma is supersonic with ion velocities of 5 to 6 kilometers/sec.

  19. PIV analysis of the homogeneity of energy deposition during development of a plasma actuator channel

    NASA Astrophysics Data System (ADS)

    Glazyrin, F. N.; Znamenskaya, I. A.; Mursenkova, I. V.; Naumov, D. S.; Sysoev, N. N.

    2016-01-01

    Nonstationary velocity fields that arise during the development of flows behind shock (blast) waves initiated by pulsed surface sliding discharge in air at a pressure of (2-4) × 104 Pa have been experimentally studied by the particle image velocimetry (PIV) technique. Plasma sheets (nanosecond discharges slipping over a dielectric surface) were initiated on walls of a rectangular chamber. Spatial analysis of the shape of shock-wave fronts and the distribution of flow velocities behind these waves showed that the pulsed energy deposition is homogeneous along discharge channels of a plasma sheet, while the integral visible plasma glow intensity decreases in the direction of channel propagation.

  20. Analysis of mass transport in an atmospheric pressure remote plasma-enhanced chemical vapor deposition process

    SciTech Connect

    Cardoso, R. P.; Belmonte, T.; Henrion, G.; Gries, T.; Tixhon, E.

    2010-01-15

    In remote microwave plasma enhanced chemical vapor deposition processes operated at atmospheric pressure, high deposition rates are associated with the localization of precursors on the treated surface. We show that mass transport can be advantageously ensured by convection for the heavier precursor, the lighter being driven by turbulent diffusion toward the surface. Transport by laminar diffusion is negligible. The use of high flow rates is mandatory to have a good mixing of species. The use of an injection nozzle with micrometer-sized hole enables us to define accurately the reaction area between the reactive species. The localization of the flow leads to high deposition rates by confining the reactive species over a small area, the deposition yield being therefore very high. Increasing the temperature modifies nonlinearly the deposition rates and the coating properties.

  1. From plasma immersion ion implantation to deposition: A historical perspective on principles and trends

    SciTech Connect

    Anders, Andre

    2001-06-14

    Plasma immersion techniques of surface modification are known under a myriad of names. The family of techniques reaches from pure plasma ion implantation, to ion implantation and deposition hybrid modes, to modes that are essentially plasma film deposition with substrate bias. In the most general sense, all plasma immersion techniques have in common that the surface of a substrate (target) is exposed to plasma and that relatively high substrate bias is applied. The bias is usually pulsed. In this review, the roots of immersion techniques are explored, some going back to the 1800s, followed by a discussion of the groundbreaking works of Adler and Conrad in the 1980s. In the 1990s, plasma immersion techniques matured in theoretical understanding, scaling, and the range of applications. First commercial facilities are now operational. Various immersion concepts are compiled and explained in this review. While gas (often nitrogen) ion implantation dominated the early years, film-forming immersion techniques and semiconductor processing gained importance. In the 1980s and 1990s we have seen exponential growth of the field but signs of slowdown are clear since 1998. Nevertheless, plasma immersion techniques have found, and will continue to have, an important place among surface modification techniques.

  2. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    SciTech Connect

    Dechana, A.; Thamboon, P.; Boonyawan, D.

    2014-10-15

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al{sub 2}O{sub 3} layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al{sub 2}O{sub 3} films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

  3. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    NASA Astrophysics Data System (ADS)

    Dechana, A.; Thamboon, P.; Boonyawan, D.

    2014-10-01

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al2O3 layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al2O3 films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

  4. Versatile high rate plasma deposition and processing with very high frequency excitation

    SciTech Connect

    Heintze, M.

    1997-07-01

    The interest in plasma deposition using very high frequency (VHF) excitation arose after the preparation of a-Si:H at high growth rates was demonstrated. Subsequently the improved process flexibility and the control of material properties offered by the variation of the plasma excitation frequency was recognized. The preparation of amorphous and microcrystalline thin films in a VHF-plasma is described. The increased growth rates have been attributed to an enhancement of film precursor formation at VHF, to the decreased sheath thickness as well as to an enhancement of the surface reactivity by positive ions. Plasma diagnostic investigations show that the parameters mainly affected by the excitation frequency are the ion flux to the electrodes as well as the sheaths potentials and widths, rather than the plasma density. 55 refs., 13 figs.

  5. Photocatalytic property of titanium dioxide thin films deposited by radio frequency magnetron sputtering in argon and water vapour plasma

    NASA Astrophysics Data System (ADS)

    Sirghi, L.; Hatanaka, Y.; Sakaguchi, K.

    2015-10-01

    The present work is investigating the photocatalytic activity of TiO2 thin films deposited by radiofrequency magnetron sputtering of a pure TiO2 target in Ar and Ar/H2O (pressure ratio 40/3) plasmas. Optical absorption, structure, surface morphology and chemical structure of the deposited films were comparatively studied. The films were amorphous and included a large amount of hydroxyl groups (about 5% of oxygen atoms were bounded to hydrogen) irrespective of the intentional content of water in the deposition chamber. Incorporation of hydroxyl groups in the film deposited in pure Ar plasma is explained as contamination of the working gas with water molecules desorbed by plasma from the deposition chamber walls. However, intentional input of water vapour into the discharge chamber decreased the deposition speed and roughness of the deposited films. The good photocatalytic activity of the deposited films could be attributed hydroxyl groups in their structures.

  6. Rapid Deposition of Titanium Oxide and Zinc Oxide Films by Solution Precursor Plasma Spray

    NASA Astrophysics Data System (ADS)

    Ando, Yasutaka

    In order to develop a high rate atmospheric film deposition process for functional films, as a basic study, deposition of titanium oxide film and zinc oxide film by solution precursor plasma spray (SPPS) was conducted in open air. Consequently, in the case of titanium oxide film deposition, anantase film and amorphous film as well as rutile film could be deposited by varying the deposition distance. In the case of anatase dominant film, photo-catalytic properties of the films could be confirmed by wettability test. In addition, the dye sensitized sollar cell (DSC) using the TiO2 film deposited by this SPPS technique as photo voltaic device generates 49mV in OCV. On the other hand, in the case of zinc oxide film deposition, it was proved that well crystallized ZnO films with photo catalytic properties could be deposited. From these results, this process was found to have high potential for high rate functional film deposition process conducted in the air.

  7. Bipolar resistive switching properties of AlN films deposited by plasma-enhanced atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Zhang, Qilong; Yang, Hui; Wu, Huayu; Zhou, Juehui; Hu, Liang

    2014-10-01

    AlN thin films deposited by plasma-enhanced atomic layer deposition (PEALD) have been used to investigate the resistive switching (RS) behavior. The bipolar RS properties were observed in the Cu/PEALD-AlN/Pt devices, which are induced upon the formation/disruption of Cu conducting filaments, as confirmed by the temperature dependent resistances relationships at different resistance states. The resistance ratio of the high and low resistance states (HRS/LRS) is 102-105. The dominant conduction mechanisms at HRS and LRS are trap-controlled space charge limited current and Ohmic behavior, respectively. This study demonstrated that the PEALD-AlN films have a great potential for the applications in high-density resistance random access memory.

  8. Temperature-independent formation of Au nanoparticles in ionic liquids by arc plasma deposition

    NASA Astrophysics Data System (ADS)

    Hatakeyama, Yoshikiyo; Kimura, Satoshi; Kameyama, Tatsuya; Agawa, Yoshiaki; Tanaka, Hiroyuki; Judai, Ken; Torimoto, Tsukasa; Nishikawa, Keiko

    2016-08-01

    An effective preparation method of Au nanoparticles (NPs) is presented, wherein an arc plasma deposition technique is combined with ionic liquids (ILs) used as capture media. This method requires no chemical reaction. By selecting ILs, size-controlled Au NPs are produced easily and on a massive scale.

  9. Lithium phosphorous oxynitride films synthesized by a plasma-assisted directed vapor deposition approach

    SciTech Connect

    Kim, Yoon Gu; Wadley, H. N. G.

    2008-01-15

    A plasma-assisted directed vapor deposition approach has been explored for the synthesis of lithium phosphorous oxynitride (Lipon) thin films. A Li{sub 3}PO{sub 4} source was first evaporated using a high voltage electron beam and the resulting vapor entrained in a nitrogen-doped supersonic helium gas jet and deposited on a substrate at ambient temperature. This approach failed to incorporate significant concentrations of nitrogen in the films. A hollow cathode technique was then used to create an argon plasma that enabled partial ionization of both the Li{sub 3}PO{sub 4} vapor and nitrogen gas just above the substrate surface. The plasma-enhanced deposition process greatly increased the gas phase and surface reactivity of the system and facilitated the synthesis and high rate deposition of amorphous Lipon films with the N/P ratios between 0.39 and 1.49. Manipulation of the plasma-enhanced process conditions also enabled control of the pore morphology and significantly affected the ionic transport properties of these films. This enabled the synthesis of electrolyte films with lithium ion conductivities in the 10{sup -7}-10{sup -8} S/m range. They appear to be well suited for thin-film battery applications.

  10. Ion enhanced deposition by dual titanium and acetylene plasma immersion ion implantation

    NASA Astrophysics Data System (ADS)

    Zeng, Z. M.; Tian, X. B.; Chu, P. K.

    2003-01-01

    Plasma immersion ion implantation and deposition (PIII-D) offers a non-line-of-sight fabrication method for various types of thin films on steels to improve the surface properties. In this work, titanium films were first deposited on 9Cr18 (AISI440) stainless bearing steel by metal plasma immersion ion implantation and deposition (MePIII-D) using a titanium vacuum arc plasma source. Afterwards, carbon implantation and carbon film deposition were performed by acetylene (C2H2) plasma immersion ion implantation. Multiple-layered structures with superior properties were produced by conducting Ti MePIII-D + C2H2 PIII successively. The composition and structure of the films were investigated employing Auger electron spectroscopy and Raman spectroscopy. It is shown that the mixing for Ti and C atoms is much better when the target bias is higher during Ti MePIII-D. A top diamond-like carbon layer and a titanium oxycarbide layer are formed on the 9Cr18 steel surface. The wear test results indicate that this dual PIII-D method can significantly enhance the wear properties and decrease the surface friction coefficient of 9Cr18 steel.

  11. Plasma deposition of silver nanoparticles on ultrafiltration membranes: antibacterial and anti-biofouling properties

    PubMed Central

    Cruz, Mercedes Cecilia; Ruano, Gustavo; Wolf, Marcus; Hecker, Dominic; Vidaurre, Elza Castro; Schmittgens, Ralph; Rajal, Verónica Beatriz

    2015-01-01

    A novel and versatile plasma reactor was used to modify Polyethersulphone commercial membranes. The equipment was applied to: i) functionalize the membranes with low-temperature plasmas, ii) deposit a film of poly(methyl methacrylate) (PMMA) by Plasma Enhanced Chemical Vapor Deposition (PECVD) and, iii) deposit silver nanoparticles (SNP) by Gas Flow Sputtering. Each modification process was performed in the same reactor consecutively, without exposure of the membranes to atmospheric air. Scanning electron microscopy and transmission electron microscopy were used to characterize the particles and modified membranes. SNP are evenly distributed on the membrane surface. Particle fixation and transport inside membranes were assessed before- and after-washing assays by X-ray photoelectron spectroscopy depth profiling analysis. PMMA addition improved SNP fixation. Plasma-treated membranes showed higher hydrophilicity. Anti-biofouling activity was successfully achieved against Gram-positive (Enterococcus faecalis) and -negative (Salmonella Typhimurium) bacteria. Therefore, disinfection by ultrafiltration showed substantial resistance to biofouling. The post-synthesis functionalization process developed provides a more efficient fabrication route for anti-biofouling and anti-bacterial membranes used in the water treatment field. To the best of our knowledge, this is the first report of a gas phase condensation process combined with a PECVD procedure in order to deposit SNP on commercial membranes to inhibit biofouling formation. PMID:26166926

  12. Correlations between plasma variables and the deposition process of Si films from chlorosilanes in low pressure RF plasma of argon and hydrogen

    NASA Technical Reports Server (NTRS)

    Avni, R.; Carmi, U.; Grill, A.; Manory, R.; Grossman, E.

    1984-01-01

    The dissociation of chlorosilanes to silicon and its deposition on a solid substrate in a RF plasma of mixtures of argon and hydrogen were investigated as a function of the macrovariables of the plasma. The dissociation mechanism of chlorosilanes and HCl as well as the formation of Si in the plasma state were studied by sampling the plasma with a quadrupole mass spectrometer. Macrovariables such as pressure, net RF power input and locations in the plasma reactor strongly influence the kinetics of dissociation. The deposition process of microcrystalline silicon films and its chlorine contamination were correlated to the dissociation mechanism of chlorosilanes and HCl.

  13. Spectroscopic ellipsometry study of hydrogenated amorphous silicon carbon alloy films deposited by plasma enhanced chemical vapor deposition

    SciTech Connect

    Basa, D. K.; Abbate, G.; Ambrosone, G.; Marino, A.; Coscia, U.

    2010-01-15

    The optical properties of the hydrogenated amorphous silicon carbon alloy films, prepared by plasma enhanced chemical vapor deposition technique from silane and methane gas mixture diluted in helium, have been investigated using variable angle spectroscopic ellipsometry in the photon energy range from 0.73 to 4.59 eV. Tauc-Lorentz model has been employed for the analysis of the optical spectra and it has been demonstrated that the model parameters are correlated with the carbon content as well as to the structural properties of the studied films.

  14. Controlled deposition of plasma activated coatings on zirconium substrates

    NASA Astrophysics Data System (ADS)

    Akhavan, Behnam; Bilek, Marcela

    2015-12-01

    Zirconium-based alloys are promising materials for orthopedic prostheses due to their low toxicity, superb corrosion resistivity, and favorable mechanical properties. The integration of such bio-implantable devices with local host tissues can strongly be improved by the development of a plasma polymerized acetylene and nitrogen (PPAN) that immobilizes bio-active molecules. The surface chemistry of PPAN is critically important as it plays a key role in affecting the surface free energy that alters the functionality of bio-active molecules at the surface. The cross-linking degree of PPAN is another key property that directly influences the water-permeability and thus also the stability of films in aqueous media. In this study we demonstrate that by simply tuning the zirconium bias voltage, control over the surface chemistry and cross-linking degree of PANN is achieved.

  15. Characterization of bismuth nanospheres deposited by plasma focus device

    SciTech Connect

    Ahmad, M.; Al-Hawat, Sh.; Akel, M.; Mrad, O.

    2015-02-14

    A new method for producing thin layer of bismuth nanospheres based on the use of low energy plasma focus device is demonstrated. Various techniques such as scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been used to characterize the morphology and the composition of the nanospheres. Experimental parameters may be adjusted to favour the formation of bismuth nanospheres instead of microspheres. Therefore, the formation of large surface of homogeneous layer of bismuth nanospheres with sizes of below 100 nm can be obtained. The natural snowball phenomenon is observed to be reproduced in nanoscale where spheres roll over the small nanospheres and grow up to bigger sizes that can reach micro dimensions. The comet-like structure, a reverse phenomenon to snowball is also observed.

  16. Characterization of bismuth nanospheres deposited by plasma focus device

    NASA Astrophysics Data System (ADS)

    Ahmad, M.; Al-Hawat, Sh.; Akel, M.; Mrad, O.

    2015-02-01

    A new method for producing thin layer of bismuth nanospheres based on the use of low energy plasma focus device is demonstrated. Various techniques such as scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been used to characterize the morphology and the composition of the nanospheres. Experimental parameters may be adjusted to favour the formation of bismuth nanospheres instead of microspheres. Therefore, the formation of large surface of homogeneous layer of bismuth nanospheres with sizes of below 100 nm can be obtained. The natural snowball phenomenon is observed to be reproduced in nanoscale where spheres roll over the small nanospheres and grow up to bigger sizes that can reach micro dimensions. The comet-like structure, a reverse phenomenon to snowball is also observed.

  17. Optical emission diagnostics of plasmas in chemical vapor deposition of single-crystal diamond

    SciTech Connect

    Hemawan, Kadek W. Hemley, Russell J.

    2015-11-15

    A key aspect of single crystal diamond growth via microwave plasma chemical vapor deposition is in-process control of the local plasma–substrate environment, that is, plasma gas phase concentrations of activated species at the plasma boundary layer near the substrate surface. Emission spectra of the plasma relative to the diamond substrate inside the microwave plasma reactor chamber have been analyzed via optical emission spectroscopy. The spectra of radical species such as CH, C{sub 2}, and H (Balmer series) important for diamond growth were identified and analyzed. The emission intensities of these electronically excited species were found to be more dependent on operating pressure than on microwave power. Plasma gas temperatures were calculated from measurements of the C{sub 2} Swan band (d{sup 3}Π → a{sup 3}Π transition) system. The plasma gas temperature ranges from 2800 to 3400 K depending on the spatial location of the plasma ball, microwave power and operating pressure. Addition of Ar into CH{sub 4}+H{sub 2} plasma input gas mixture has little influence on the Hα, Hβ, and Hγ intensities and single-crystal diamond growth rates.

  18. Oxygen-Plasma-Treated Indium-Tin-Oxide Films on Nonalkali Glass Deposited by Super Density Arc Plasma Ion Plating

    NASA Astrophysics Data System (ADS)

    Kim, Soo Young; Hong, Kihyon; Son, Jun Ho; Jung, Gwan Ho; Lee, Jong-Lam; Choi, Kyu Han; Song, Kyu Ho; Ahn, Kyung Chul

    2008-02-01

    The effects of O2 plasma treatment on both the chemical composition and work function of an indium-tin-oxide (ITO) film were investigated. ITO films were deposited on non-alkali glass substrate by super density arc plasma ion plating for application in active-matrix organic light-emitting diodes (OLEDs). The water contact angle decreased from 38 to 11° as the ITO films were treated with O2 plasma for 60 s at a plasma power of 150 W, indicating an increase in the hydrophilicity of the surface. It was found that there were no distinct changes in the microstructure or electrical properties of the ITO films with O2 plasma treatment. Synchrotron radiation photoemission spectroscopy data revealed that O2 plasma treatment decreased the amount of carbon contamination and increased the number of unscreened states of In3+ and (O2)2- peroxo species. This played the role of increasing the work function of the ITO films by 1.7 eV. As a result, the turn-on voltage of the OLED decreased markedly from 24 to 8 V and the maximum luminance value of the OLED increased to 2500 cd/m2.

  19. Flexible system for multiple plasma immersion ion implantation-deposition processes

    NASA Astrophysics Data System (ADS)

    Tian, Xiubo; Fu, Ricky K. Y.; Chu, Paul K.; Anders, Andre; Gong, Chunzhi; Yang, Shiqin

    2003-12-01

    Multiple plasma immersion ion implantation-deposition offers better flexibility compared to other thin film deposition techniques with regard to process optimization. The plasmas may be based on either cathodic arc plasmas (metal ions) or gas plasmas (gas ions) or both of them. Processing parameters such as pulsing frequency, pulse duration, bias voltage amplitude, and so on, that critically affect the film structure, internal stress, surface morphology, and other surface properties can be adjusted relatively easily to optimize the process. The plasma density can be readily controlled via the input power to obtain the desirable gas-to-metal ion ratios in the films. The high-voltage pulses can be applied to the samples within (in-duration mode), before (before-duration mode), or after (after-duration mode) the firing of the cathodic arcs. Consequently, dynamic ion beam assisted deposition processes incorporating various mixes of gas and metal ions can be achieved to yield thin films with the desirable properties. The immersion configuration provides to a certain degree the ability to treat components that are large and possess irregular geometries without resorting to complex sample manipulation or beam scanning. In this article we describe the hardware functions of such a system, voltage-current behavior to satisfy the needs of different processes, as well as typical experimental results.

  20. Atomic Layer Deposition of Silicon Nitride from Bis(tert-butylamino)silane and N2 Plasma.

    PubMed

    Knoops, Harm C M; Braeken, Eline M J; de Peuter, Koen; Potts, Stephen E; Haukka, Suvi; Pore, Viljami; Kessels, Wilhelmus M M

    2015-09-01

    Atomic layer deposition (ALD) of silicon nitride (SiNx) is deemed essential for a variety of applications in nanoelectronics, such as gate spacer layers in transistors. In this work an ALD process using bis(tert-butylamino)silane (BTBAS) and N2 plasma was developed and studied. The process exhibited a wide temperature window starting from room temperature up to 500 °C. The material properties and wet-etch rates were investigated as a function of plasma exposure time, plasma pressure, and substrate table temperature. Table temperatures of 300-500 °C yielded a high material quality and a composition close to Si3N4 was obtained at 500 °C (N/Si=1.4±0.1, mass density=2.9±0.1 g/cm3, refractive index=1.96±0.03). Low wet-etch rates of ∼1 nm/min were obtained for films deposited at table temperatures of 400 °C and higher, similar to that achieved in the literature using low-pressure chemical vapor deposition of SiNx at >700 °C. For novel applications requiring significantly lower temperatures, the temperature window from room temperature to 200 °C can be a solution, where relatively high material quality was obtained when operating at low plasma pressures or long plasma exposure times. PMID:26305370

  1. Plasma-enhanced chemical vapor deposition of graphene on copper substrates

    SciTech Connect

    Woehrl, Nicolas Schulz, Stephan; Ochedowski, Oliver; Gottlieb, Steven; Shibasaki, Kosuke

    2014-04-15

    A plasma enhanced vapor deposition process is used to synthesize graphene from a hydrogen/methane gas mixture on copper samples. The graphene samples were transferred onto SiO{sub 2} substrates and characterized by Raman spectroscopic mapping and atomic force microscope topographical mapping. Analysis of the Raman bands shows that the deposited graphene is clearly SLG and that the sheets are deposited on large areas of several mm{sup 2}. The defect density in the graphene sheets is calculated using Raman measurements and the influence of the process pressure on the defect density is measured. Furthermore the origin of these defects is discussed with respect to the process parameters and hence the plasma environment.

  2. Surface and corrosion characteristics of carbon plasma implanted and deposited nickel-titanium alloy

    SciTech Connect

    Poon, R.W.Y.; Liu, X.Y.; Chung, C.Y.; Chu, P.K.; Yeung, K.W.K.; Lu, W.W.; Cheung, K.M.C.

    2005-05-01

    Nickel-titanium shape memory alloys (NiTi) are potentially useful in orthopedic implants on account of their super-elastic and shape memory properties. However, the materials are prone to surface corrosion and the most common problem is out-diffusion of harmful Ni ions from the substrate into body tissues and fluids. In order to improve the corrosion resistance and related surface properties, we used the technique of plasma immersion ion implantation and deposition to deposit an amorphous hydrogenated carbon coating onto NiTi and implant carbon into NiTi. Both the deposited amorphous carbon film and carbon plasma implanted samples exhibit much improved corrosion resistances and surface mechanical properties and possible mechanisms are suggested.

  3. Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J.

    2015-11-01

    Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH4/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H2 into the deposition gas chemistry. Electronically excited species of CN, C2, Ar, N2, CH, Hβ, and Hα were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T2g phonon at 1333 cm-1 peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit "coral" and "cauliflower-like" morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.

  4. Direct deposition of aluminum oxide gate dielectric on graphene channel using nitrogen plasma treatment

    SciTech Connect

    Lim, Taekyung; Kim, Dongchool; Ju, Sanghyun

    2013-07-01

    Deposition of high-quality dielectric on a graphene channel is an essential technology to overcome structural constraints for the development of nano-electronic devices. In this study, we investigated a method for directly depositing aluminum oxide (Al{sub 2}O{sub 3}) on a graphene channel through nitrogen plasma treatment. The deposited Al{sub 2}O{sub 3} thin film on graphene demonstrated excellent dielectric properties with negligible charge trapping and de-trapping in the gate insulator. A top-gate-structural graphene transistor was fabricated using Al{sub 2}O{sub 3} as the gate dielectric with nitrogen plasma treatment on graphene channel region, and exhibited p-type transistor characteristics.

  5. Plasma-enhanced chemical vapor deposition of amorphous Si on graphene

    NASA Astrophysics Data System (ADS)

    Lupina, G.; Strobel, C.; Dabrowski, J.; Lippert, G.; Kitzmann, J.; Krause, H. M.; Wenger, Ch.; Lukosius, M.; Wolff, A.; Albert, M.; Bartha, J. W.

    2016-05-01

    Plasma-enhanced chemical vapor deposition of thin a-Si:H layers on transferred large area graphene is investigated. Radio frequency (RF, 13.56 MHz) and very high frequency (VHF, 140 MHz) plasma processes are compared. Both methods provide conformal coating of graphene with Si layers as thin as 20 nm without any additional seed layer. The RF plasma process results in amorphization of the graphene layer. In contrast, the VHF process keeps the high crystalline quality of the graphene layer almost intact. Correlation analysis of Raman 2D and G band positions indicates that Si deposition induces reduction of the initial doping in graphene and an increase of compressive strain. Upon rapid thermal annealing, the amorphous Si layer undergoes dehydrogenation and transformation into a polycrystalline film, whereby a high crystalline quality of graphene is preserved.

  6. Plasma-enhanced chemical vapor deposition method to coat micropipettes with diamond-like carbon

    SciTech Connect

    Kakuta, Naoto; Watanabe, Mayu; Yamada, Yukio; Okuyama, Naoki; Mabuchi, Kunihiko

    2005-07-15

    This article provides a simple method for coating glass micropipettes with diamond-like carbon (DLC) through plasma-enhanced chemical vapor deposition. The apparatus uses a cathode that is a thin-metal-coated micropipette itself and an anode that is a meshed cylinder with its cylinder axis along the micropipette length. To produce a uniform plasma and prevent a temperature increase at the tip due to ion collision concentration, we investigated the effect of the height and diameter of the meshed cylindrical anode on the plasma. Intermittent deposition is also effective for inhibiting the temperature rise and producing high quality DLC films. Measured Raman spectra and electric resistivity indicate that a DLC film suitable for use as an insulating film can be produced on the micropipette. This coating method should also be useful for other extremely small probes.

  7. Simultaneous Power Deposition Detection of Two EC Beams with the BIS Analysis in Moving TCV Plasmas

    NASA Astrophysics Data System (ADS)

    Curchod, L.; Pochelon, A.; Decker, J.; Felici, F.; Goodman, T. P.; Moret, J.-M.; Paley, J. I.

    2009-11-01

    Modulation of power amplitude is a widespread to determine the radial absorption profile of externally launched power in fusion plasmas. There are many techniques to analyze the plasma response to such a modulation. The break-in-slope (BIS) analysis can draw an estimated power deposition profile for each power step up. In this paper, the BIS analysis is used to monitor the power deposition location of one or two EC power beams simultaneously in a non-stationary plasma being displaced vertically in the TCV tokamak vessel. Except from radial discrepancies, the results have high time resolution and compare well with simulations from the R2D2-C3PO-LUKE ray-tracing and Fokker-Planck code suite.

  8. Plasma Spray-PVD: A New Thermal Spray Process to Deposit Out of the Vapor Phase

    NASA Astrophysics Data System (ADS)

    von Niessen, Konstantin; Gindrat, Malko

    2011-06-01

    Plasma spray-physical vapor deposition (PS-PVD) is a low pressure plasma spray technology recently developed by Sulzer Metco AG (Switzerland). Even though it is a thermal spray process, it can deposit coatings out of the vapor phase. The basis of PS-PVD is the low pressure plasma spraying (LPPS) technology that has been well established in industry for several years. In comparison to conventional vacuum plasma spraying (VPS) or low pressure plasma spraying (LPPS), the new proposed process uses a high energy plasma gun operated at a reduced work pressure of 0.1 kPa (1 mbar). Owing to the high energy plasma and further reduced work pressure, PS-PVD is able to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional physical vapor deposition (PVD) technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and electron beam-physical vapor deposition (EB-PVD) coatings. In contrast to EB-PVD, PS-PVD incorporates the vaporized coating material into a supersonic plasma plume. Owing to the forced gas stream of the plasma jet, complex shaped parts such as multi-airfoil turbine vanes can be coated with columnar thermal barrier coatings using PS-PVD. Even shadowed areas and areas which are not in the line of sight of the coating source can be coated homogeneously. This article reports on the progress made by Sulzer Metco in developing a thermal spray process to produce coatings out of the vapor phase. Columnar thermal barrier coatings made of Yttria-stabilized Zircona (YSZ) are optimized to serve in a turbine engine. This process includes not only preferable coating properties such as strain tolerance and erosion

  9. Transport and Deposition of 13c From Methane Injection into Detached H-Mode Plasmas in DIII-D

    SciTech Connect

    Wampler, W R; McLean, A G; Allen, S L; Brooks, N H; Elder, J D; Fenstermacher, M E; Groth, M; Stangeby, P C; West, W P; Whyte, D G

    2006-06-01

    Experiments are described which examine the transport and deposition of carbon entering the main plasma scrape-off layer in DIII-D. {sup 13}CH{sub 4} was injected from a toroidally symmetric source into the crown of lower single-null detached ELMy H-mode plasmas. {sup 13}C deposition, mapped by nuclear reaction analysis of tiles, was high at the inner divertor but absent at the outer divertor, as found previously for low density L-mode plasmas. This asymmetry indicates that ionized carbon is swept towards the inner divertor by a fast flow in the scrape-off layer. In the private flux region between inner and outer strike points, carbon deposition was low for L-mode but high for the H-mode plasmas. OEDGE modeling reproduces observed deposition patterns and indicates that neutral carbon dominates deposition in the divertor from detached H-mode plasmas.

  10. Behavior of incorporated nitrogen in plasma-nitrided silicon oxide formed by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Shinoda, Nao; Itokawa, Hiroshi; Fujitsuka, Ryota; Sekine, Katsuyuki; Onoue, Seiji; Tonotani, Junichi

    2016-04-01

    The behavior of nitrogen (N) atoms in plasma-nitrided silicon oxide (SiO2) formed by chemical vapor deposition (CVD) was characterized by physical analysis and from electrical properties. The changes in the chemical bonding and distribution of N in plasma-nitrided SiO2 were investigated for different subsequent processes. N-Si3, N-Si2O, and N2 are formed in a SiO2 film by plasma nitridation. N2 molecules diffuse out during annealing at temperatures higher than 900 °C. NH species are generated from N2 molecules and H in the SiO2 film with subsequent oxide deposition using O3 as an oxidant. The capacitance-voltage (C-V) curves of metal-oxide-semiconductor (MOS) capacitors are obtained. The negative shift of the C-V curve is caused by the increase in the density of positive fix charge traps in CVD-SiO2 induced by plasma nitridation. The C-V curve of plasma-nitrided SiO2 subjected to annealing shifts to the positive direction and that subjected to the subsequent oxide deposition shifts markedly to the negative direction. It is clarified that the density of positive charge fixed traps in plasma-nitrided SiO2 films decrease because the amount of N2 molecules is decreased by annealing, and that the density of traps increases because NH species are generated and move to the interface between SiO2 and the Si substrate with the subsequent oxide deposition.

  11. Study on electrostatic and electromagnetic probes operated in ceramic and metallic depositing plasmas

    NASA Astrophysics Data System (ADS)

    Styrnoll, T.; Bienholz, S.; Lapke, M.; Awakowicz, P.

    2014-04-01

    This paper discusses plasma probe diagnostics, namely the multipole resonance probe (MRP) and Langmuir probe (LP), operated in depositing plasmas. The aim of this work is to show that the combination of both probes provides stable and robust measurements and clear determination of plasma parameters for metallic and ceramic coating processes. The probes use different approaches to determine plasma parameters, e.g. electron density ne and electron temperature Te. The LP is a well-established plasma diagnostic, and its applicability in technological plasmas is well documented. The LP is a dc probe that performs a voltage sweep and analyses the measured current, which makes it insensitive against conductive metallic coating. However, once the LP is dielectrically coated with a ceramic film, its functionality is constricted. In contrast, the MRP was recently presented as a monitoring tool, which is insensitive to coating with dielectric ceramics. It is a new plasma diagnostic based on the concept of active plasma resonance spectroscopy, which uses the universal characteristic of all plasmas to resonate on or near the electron plasma frequency. The MRP emits a frequency sweep and the absorption of the signal, the |S11| parameter, is analysed. Since the MRP concept is based on electromagnetic waves, which are able to transmit dielectrics, it is insensitive to dielectric coatings. But once the MRP is metallized with a thin conductive film, no undisturbed RF-signal can be emitted into the plasma, which leads to falsified plasma parameter. In order to compare both systems, during metallic or dielectric coating, the probes are operated in a magnetron CCP, which is equipped with a titanium target. We present measurements in metallic and dielectric coating processes with both probes and elaborate advantages and problems of each probe operated in each coating environment.

  12. Surface modification of biomaterials by pulsed laser ablation deposition and plasma/gamma polymerization

    NASA Astrophysics Data System (ADS)

    Rau, Kaustubh R.

    Surface modification of stainless-steel was carried out by two different methods: pulsed laser ablation deposition (PLAD) and a combined plasma/gamma process. A potential application was the surface modification of endovascular stents, to enhance biocompatibility. The pulsed laser ablation deposition process, had not been previously reported for modifying stents and represented a unique and potentially important method for surface modification of biomaterials. Polydimethylsiloxane (PDMS) elatomer was studied using the PLAD technique. Cross- linked PDMS was deemed important because of its general use for biomedical implants and devices as well as in other fields. Furthermore, PDMS deposition using PLAD had not been previously studied and any information gained on its ablation characteristics could be important scientifically and technologically. The studies reported here showed that the deposited silicone film properties had a dependence on the laser energy density incident on the target. Smooth, hydrophobic, silicone-like films were deposited at low energy densities (100-150 mJ/cm2). At high energy densities (>200 mJ/cm2), the films had an higher oxygen content than PDMS, were hydrophilic and tended to show a more particulate morphology. It was also determined that (1)the deposited films were stable and extremely adherent to the substrate, (2)silicone deposition exhibited an `incubation effect' which led to the film properties changing with laser pulse number and (3)films deposited under high vacuum were similar to films deposited at low vacuum levels. The mechanical properties of the PLAD films were determined by nanomechanical measurements which are based on the Atomic Force Microscope (AFM). From these measurements, it was possible to determine the modulus of the films and also study their scratch resistance. Such measurement techniques represent a significant advance over current state-of-the-art thin film characterization methods. An empirical model for

  13. Conformal encapsulation of three-dimensional, bioresorbable polymeric scaffolds using plasma-enhanced chemical vapor deposition.

    PubMed

    Hawker, Morgan J; Pegalajar-Jurado, Adoracion; Fisher, Ellen R

    2014-10-21

    Bioresorbable polymers such as poly(ε-caprolactone) (PCL) have a multitude of potential biomaterial applications such as controlled-release drug delivery and regenerative tissue engineering. For such biological applications, the fabrication of porous three-dimensional bioresorbable materials with tunable surface chemistry is critical to maximize their surface-to-volume ratio, mimic the extracellular matrix, and increase drug-loading capacity. Here, two different fluorocarbon (FC) precursors (octofluoropropane (C3F8) and hexafluoropropylene oxide (HFPO)) were used to deposit FC films on PCL scaffolds using plasma-enhanced chemical vapor deposition (PECVD). These two coating systems were chosen with the intent of modifying the scaffold surfaces to be bio-nonreactive while maintaining desirable bulk properties of the scaffold. X-ray photoelectron spectroscopy showed high-CF2 content films were deposited on both the exterior and interior of PCL scaffolds and that deposition behavior is PECVD system specific. Scanning electron microscopy data confirmed that FC film deposition yielded conformal rather than blanket coatings as the porous scaffold structure was maintained after plasma treatment. Treated scaffolds seeded with human dermal fibroblasts (HDF) demonstrate that the cells do not attach after 72 h and that the scaffolds are noncytotoxic to HDF. This work demonstrates conformal FC coatings can be deposited on 3D polymeric scaffolds using PECVD to fabricate 3D bio-nonreactive materials. PMID:25247481

  14. Energy deposition characteristics of nanosecond dielectric barrier discharge plasma actuators: Influence of dielectric material

    NASA Astrophysics Data System (ADS)

    Correale, G.; Winkel, R.; Kotsonis, M.

    2015-08-01

    An experimental study aimed at the characterization of energy deposition of nanosecond Dielectric Barrier Discharge (ns-DBD) plasma actuators was carried out. Special attention was given on the effect of the thickness and material used for dielectric barrier. The selected materials for this study were polyimide film (Kapton), polyamide based nylon (PA2200), and silicone rubber. Schlieren measurements were carried out in quiescent air conditions in order to observe density gradients induced by energy deposited. Size of heated area was used to qualify the energy deposition coupled with electrical power measurements performed using the back-current shunt technique. Additionally, light intensity measurements showed a different nature of discharge based upon the material used for barrier, for a fixed thickness and frequency of discharge. Finally, a characterisation study was performed for the three tested materials. Dielectric constant, volume resistivity, and thermal conductivity were measured. Strong trends between the control parameters and the energy deposited into the fluid during the discharge were observed. Results indicate that efficiency of energy deposition mechanism relative to the thickness of the barrier strongly depends upon the material used for the dielectric barrier itself. In general, a high dielectric strength and a low volumetric resistivity are preferred for a barrier, together with a high heat capacitance and a low thermal conductivity coefficient in order to maximize the efficiency of the thermal energy deposition induced by an ns-DBD plasma actuator.

  15. Laser-induced metal plasmas for pulsed laser deposition of metal-oxide thin films

    NASA Astrophysics Data System (ADS)

    Wagenaars, Erik; Colgan, James; Rajendiran, Sudha; Rossall, Andrew

    2015-09-01

    Metal and metal-oxide thin films, e.g. ZnO, MgO, Al2O3 and TiO2, are widely used in e.g. microelectronics, catalysts, photonics and displays. Pulsed Laser Deposition (PLD) is a plasma-based thin-film deposition technique that is highly versatile and fast, however it suffers from limitations in control of film quality due to a lack of fundamental understanding of the underlying physical processes. We present experimental and modelling studies of the initial phases of PLD: laser ablation and plume expansion. A 2D hydrodynamic code, POLLUX, is used to model the laser-solid interaction of a Zn ablation with a Nd:YAG laser. In this early phase of PLD, the plasma plume has temperatures of about 10 eV, is highly ionized, and travels with a velocity of about 10-100 km/sec away from the target. Subsequently, the plasma enters the plume expansion phase in which the plasma cools down and collision chemistry changes the composition of the plume. Time-integrated optical emission spectroscopy shows that Zn I and Zn II emission lines dominate the visible range of the light emission. Comparison with the Los Alamos plasma kinetics code ATOMIC shows an average temperature around 1 eV, indicating a significant drop in plasma temperature during the expansion phase. We acknowledge support from the UK Engineering and Physical Sciences Research Council (EPSRC), Grant EP/K018388/1.

  16. Influence of the oxygen plasma parameters on the atomic layer deposition of titanium dioxide.

    PubMed

    Ratzsch, Stephan; Kley, Ernst-Bernhard; Tünnermann, Andreas; Szeghalmi, Adriana

    2015-01-16

    The influence of the oxygen plasma parameters on the morphology and optical properties of TiO2 thin films has been extensively analyzed in plasma enhanced atomic layer deposition (PEALD) processes. Crystalline aggregates with the anatase phase have been identified on the film surface at a low deposition temperature (down to 70 °C) under specific plasma conditions. Up to 70% surface coverage by anatase crystallites is obtained at low oxygen gas flow rates and high plasma power. The hillocks abundance is correlated with high ion flux and electron density and with the resulting enhanced ion bombardment of the surface. Altering the plasma conditions is an important parameter besides temperature to control the morphology of the titania film for specific applications such as photocatalysis or functional optical coatings. Specifically, photocatalytic titania coatings on polymer substrates could benefit of such low temperature PEALD processes with abundant anatase crystallites; whereas optical coatings require smooth, high refractive index titania as obtained with low plasma power and high oxygen flow rate. PMID:25525676

  17. Patterned growth of carbon nanotubes obtained by high density plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Mousinho, A. P.; Mansano, R. D.

    2015-03-01

    Patterned growth of carbon nanotubes by chemical vapor deposition represents an assembly approach to place and orient nanotubes at a stage as early as when they are synthesized. In this work, the carbon nanotubes were obtained at room temperature by High Density Plasmas Chemical Vapor Deposition (HDPCVD) system. This CVD system uses a new concept of plasma generation, where a planar coil coupled to an RF system for plasma generation was used with an electrostatic shield for plasma densification. In this mode, high density plasmas are obtained. We also report the patterned growth of carbon nanotubes on full 4-in Si wafers, using pure methane plasmas and iron as precursor material (seed). Photolithography processes were used to pattern the regions on the silicon wafers. The carbon nanotubes were characterized by micro-Raman spectroscopy, the spectra showed very single-walled carbon nanotubes axial vibration modes around 1590 cm-1 and radial breathing modes (RBM) around 120-400 cm-1, confirming that high quality of the carbon nanotubes obtained in this work. The carbon nanotubes were analyzed by atomic force microscopy and scanning electron microscopy too. The results showed that is possible obtain high-aligned carbon nanotubes with patterned growth on a silicon wafer with high reproducibility and control.

  18. Open Air Silicon Deposition by Atmospheric Pressure Plasma under Local Ambient Gas Control

    NASA Astrophysics Data System (ADS)

    Naito, Teruki; Konno, Nobuaki; Yoshida, Yukihisa

    2015-09-01

    In this paper, we report open air silicon (Si) deposition by combining a silane free Si deposition technology and a newly developed local ambient gas control technology. Recently, material processing in open air has been investigated intensively. While a variety of materials have been deposited, there were only few reports on Si deposition due to the susceptibility to contamination and the hazardous nature of source materials. Since Si deposition is one of the most important processes in device fabrication, we have developed open air silicon deposition technologies in BEANS project. For a clean and safe process, a local ambient gas control head was designed. Process gas leakage was prevented by local evacuation, and air contamination was shut out by inert curtain gas. By numerical and experimental investigations, a safe and clean process condition with air contamination less than 10 ppm was achieved. Si film was deposited in open air by atmospheric pressure plasma enhanced chemical transport under the local ambient gas control. The film was microcrystalline Si with the crystallite size of 17 nm, and the Hall mobility was 2.3 cm2/V .s. These properties were comparable to those of Si films deposited in a vacuum chamber. This research has been conducted as one of the research items of New Energy and Industrial Technology Development Organization ``BEANS'' project.

  19. Growth of diamond by RF plasma-assisted chemical vapor deposition

    NASA Technical Reports Server (NTRS)

    Meyer, Duane E.; Ianno, Natale J.; Woollam, John A.; Swartzlander, A. B.; Nelson, A. J.

    1988-01-01

    A system has been designed and constructed to produce diamond particles by inductively coupled radio-frequency, plasma-assisted chemical vapor deposition. This is a low-pressure, low-temperature process used in an attempt to deposit diamond on substrates of glass, quartz, silicon, nickel, and boron nitride. Several deposition parameters have been varied including substrate temperature, gas concentration, gas pressure, total gas flow rate, RF input power, and deposition time. Analytical methods employed to determine composition and structure of the deposits include scanning electron microscopy, absorption spectroscopy, scanning Auger microprobe spectroscopy, and Raman spectroscopy. Analysis indicates that particles having a thin graphite surface, as well as diamond particles with no surface coatings, have been deposited. Deposits on quartz have exhibited optical bandgaps as high as 4.5 eV. Scanning electron microscopy analysis shows that particles are deposited on a pedestal which Auger spectroscopy indicates to be graphite. This is a phenomenon that has not been previously reported in the literature.

  20. Solid oxide fuel cell processing using plasma arc spray deposition techniques

    SciTech Connect

    Ray, E.R.; Spengler, C.J.; Herman, H.

    1991-07-01

    The Westinghouse Electric Corporation, in conjunction with the Thermal Spray Laboratory of the State University of New York, Stony Brook, investigated the fabrication of a gas-tight interconnect layer on a tubular solid oxide fuel cell with plasma arc spray deposition. The principal objective was to determine the process variables for the plasma spray deposition of an interconnect with adequate electrical conductivity and other desired properties. Plasma arc spray deposition is a process where the coating material in powder form is heated to or above its melting temperature, while being accelerated by a carrier gas stream through a high power electric arc. The molten powder particles are directed at the substrate, and on impact, form a coating consisting of many layers of overlapping, thin, lenticular particles or splats. The variables investigated were gun power, spray distance, powder feed rate, plasma gas flow rates, number of gun passes, powder size distribution, injection angle of powder into the plasma plume, vacuum or atmospheric plasma spraying, and substrate heating. Typically, coatings produced by both systems showed bands of lanthanum rich material and cracking with the coating. Preheating the substrate reduced but did not eliminate internal coating cracking. A uniformly thick, dense, adherent interconnect of the desired chemistry was finally achieved with sufficient gas- tightness to allow fabrication of cells and samples for measurement of physical and electrical properties. A cell was tested successfully at 1000{degree}C for over 1,000 hours demonstrating the mechanical, electrical, and chemical stability of a plasma-arc sprayed interconnect layer.

  1. Solid oxide fuel cell processing using plasma arc spray deposition techniques. Final report

    SciTech Connect

    Ray, E.R.; Spengler, C.J.; Herman, H.

    1991-07-01

    The Westinghouse Electric Corporation, in conjunction with the Thermal Spray Laboratory of the State University of New York, Stony Brook, investigated the fabrication of a gas-tight interconnect layer on a tubular solid oxide fuel cell with plasma arc spray deposition. The principal objective was to determine the process variables for the plasma spray deposition of an interconnect with adequate electrical conductivity and other desired properties. Plasma arc spray deposition is a process where the coating material in powder form is heated to or above its melting temperature, while being accelerated by a carrier gas stream through a high power electric arc. The molten powder particles are directed at the substrate, and on impact, form a coating consisting of many layers of overlapping, thin, lenticular particles or splats. The variables investigated were gun power, spray distance, powder feed rate, plasma gas flow rates, number of gun passes, powder size distribution, injection angle of powder into the plasma plume, vacuum or atmospheric plasma spraying, and substrate heating. Typically, coatings produced by both systems showed bands of lanthanum rich material and cracking with the coating. Preheating the substrate reduced but did not eliminate internal coating cracking. A uniformly thick, dense, adherent interconnect of the desired chemistry was finally achieved with sufficient gas- tightness to allow fabrication of cells and samples for measurement of physical and electrical properties. A cell was tested successfully at 1000{degree}C for over 1,000 hours demonstrating the mechanical, electrical, and chemical stability of a plasma-arc sprayed interconnect layer.

  2. Deposition of solid oxide fuel cell electrodes by solution precursor plasma spray

    NASA Astrophysics Data System (ADS)

    Wang, Youliang

    Porous La1-xSrxMnO3 (LSM) perovskite cathodes and Yttria Stabilized Zirconia (YSZ)-Nickel (Ni) anodes were successfully deposited by direct current arc solution precursor plasma spray (DC-SPPS), in which a solution precursor of the product material was injected into DC plasma jet. The deposition mechanisms, such as the changes in the solution precursor with the increase of temperature and the evolution of the droplet as it moved along the plasma jet, as well as the impact of the synthesized particles onto the substrate, were investigated. The effects of processing parameters on the microstructure and phase composition of the fabricated LSM cathode and Ni-YSZ anode were examined systematically using TGA/TDA, XRD and SEM. Coating deposition efficiencies and porosities as a function of processing parameters were analyzed by statistical experimental design techniques, based on which the deposition processes were optimized. In addition, the hardness and electrical resistance of the fabricated coatings were measured. From the theoretical and experimental analyses conducted, a comprehensive description of the DC-SPPS process was developed. The precursor solution droplets undergo breakup; solvent evaporation and precursor salt precipitation and crystallization; precursor salt melting and decomposition; nucleation and growth of particles of the product phase; agglomeration, sintering, and perhaps melting of these particles; and impact onto the substrate. The breakup of droplets can only occur in the short period of time after the droplets are injected into the plasma jet. Agglomeration of droplets or particles may occur at any point along the plasma plume. This work has clearly established: (a) the critical importance of droplet breakup and the agglomeration of precursors or synthesized particles in-flight in the plasma jet in determining the structure of the deposited coating, and (b) the basis of the low deposition efficiencies obtained in DC-SPPS. The microstructure and

  3. Energy deposition into heavy gas plasma via pulsed inductive theta-pinch

    NASA Astrophysics Data System (ADS)

    Pahl, Ryan Alan

    The objective of this research is to study the formation processes of a pulsed inductive plasma using heavy gases, specifically the coupling of stored capacitive energy into plasma via formation in a theta pinch coil. To aid in this research, the Missouri Plasmoid Experiment Mk. I (and later Mk. II) was created. In the first paper, the construction of differential magnetic field probes are discussed. The effects of calibration setup on B-dot probes is studied using a Helmholtz coil driven by a vector network analyzer and a pulsed-power system. Calibration in a pulsed-power environment yielded calibration factors at least 9.7% less than the vector network analyzer. In the second paper, energy deposition into various gases using a pulsed inductive test article is investigated. Experimental data are combined with a series RLC model to quantify the energy loss associated with plasma formation in Argon, Hydrogen, and Xenon at pressures from 10-100 mTorr. Plasma resistance is found to vary from 25.8-51.6 mΩ and plasma inductance varies from 41.3--47.0 nH. The greatest amount of initial capacitively stored energy that could be transferred to the plasma was 6.4 J (8.1%) of the initial 79.2 +/- 0.1 J. In the third paper, the effects of a DC preionization source on plasma formation energy is studied. The preionization source radial location is found to have negligible impact on plasma formation repeatability while voltage is found to be critical at low pressures. Without preionization, plasma formation was not possible. At 20 mTorr, 0.20 W of power was sufficient to stabilize plasma formation about the first zero-crossing of the discharge current. Increasing power to 1.49 W increased inductively coupled energy by 39%. At 200 mTorr, 4.3 mW was sufficient to produce repeatable plasma properties.

  4. Multiple substrate microwave plasma-assisted chemical vapor deposition single crystal diamond synthesis

    SciTech Connect

    Asmussen, J.; Grotjohn, T. A.; Reinhard, D. K.; Schuelke, T.; Becker, M. F.; Yaran, M. K.; King, D. J.; Wicklein, S.

    2008-07-21

    A multiple substrate, microwave plasma-assisted chemical vapor deposition synthesis process for single crystal diamond (SCD) is demonstrated using a 915 MHz reactor. Diamond synthesis was performed using input chemistries of 6-8% of CH{sub 4}/H{sub 2}, microwave input powers of 10-11.5 kW, substrate temperatures of 1100-1200 deg. C, and pressures of 110-135 Torr. The simultaneous synthesis of SCD over 70 diamond seeds yielded good quality SCD with deposition rates of 14-21 {mu}m/h. Multiple deposition runs totaling 145 h of deposition time added 1.8-2.5 mm of diamond material to each of the 70 seed crystals.

  5. Plasma membranes modified by plasma treatment or deposition as solid electrolytes for potential application in solid alkaline fuel cells.

    PubMed

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-01-01

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane. PMID:24958295

  6. Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

    PubMed Central

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-01-01

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane. PMID:24958295

  7. Drop coating deposition Raman spectroscopy of blood plasma for the detection of colorectal cancer.

    PubMed

    Li, Pengpeng; Chen, Changshui; Deng, Xiaoyuan; Mao, Hua; Jin, Shaoqin

    2015-03-01

    We have recently applied the technique of drop coating deposition Raman (DCDR) spectroscopy for colorectal cancer (CRC) detection using blood plasma. The aim of this study was to develop a more convenient and stable method based on blood plasma for noninvasive CRC detection. Significant differences are observed in DCDR spectra between healthy (n = 105) and cancer (n = 75) plasma from 15 CRC patients and 21 volunteers, particularly in the spectra that are related to proteins, nucleic acids, and β-carotene. The multivariate analysis principal components analysis and the linear discriminate analysis, together with leave-one-out, cross validation were used on DCDR spectra and yielded a sensitivity of 100% (75/75) and specificity of 98.1% (103/105) for detection of CRC. This study demonstrates that DCDR spectroscopy of blood plasma associated with multivariate statistical algorithms has the potential for the noninvasive detection of CRC. PMID:25756306

  8. INSTRUMENTS AND METHODS OF INVESTIGATION: Modification of material properties and coating deposition using plasma jets

    NASA Astrophysics Data System (ADS)

    Pogrebnyak, Alexander D.; Tyurin, Yu N.

    2005-05-01

    The review is concerned with the current status of research on the use of plasma jets for the modification of surface properties of metalware, as well as of investigations of doping and mass transfer of elements. The effect of thermal plasma parameters on the efficiency of surface processing of metal materials is discussed. The structure and properties of protective coatings produced by exposure to pulsed plasmas are analyzed. A new direction for the production of combined coatings is considered. Their structure and properties were studied by the example of Fe, Cu, steels, and alloys, including titanium alloys; the modification process was shown to be controllable by the action of pulsed plasma jets. The physical factors that affect the modification process and the coating deposition, and their effect on the structure and properties of metallic, ceramic - metal, and ceramic coatings were analyzed.

  9. Drop coating deposition Raman spectroscopy of blood plasma for the detection of colorectal cancer

    NASA Astrophysics Data System (ADS)

    Li, Pengpeng; Chen, Changshui; Deng, Xiaoyuan; Mao, Hua; Jin, Shaoqin

    2015-03-01

    We have recently applied the technique of drop coating deposition Raman (DCDR) spectroscopy for colorectal cancer (CRC) detection using blood plasma. The aim of this study was to develop a more convenient and stable method based on blood plasma for noninvasive CRC detection. Significant differences are observed in DCDR spectra between healthy (n=105) and cancer (n=75) plasma from 15 CRC patients and 21 volunteers, particularly in the spectra that are related to proteins, nucleic acids, and β-carotene. The multivariate analysis principal components analysis and the linear discriminate analysis, together with leave-one-out, cross validation were used on DCDR spectra and yielded a sensitivity of 100% (75/75) and specificity of 98.1% (103/105) for detection of CRC. This study demonstrates that DCDR spectroscopy of blood plasma associated with multivariate statistical algorithms has the potential for the noninvasive detection of CRC.

  10. Fluid modeling for plasma-enhanced direct current chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Ismagilov, Rinat R.; Khamidullin, Ildar R.; Kleshch, Victor I.; Malykhin, Sergei A.; Alexeev, Andrey M.; Obraztsov, Alexander N.

    2016-01-01

    A self-consistent continuum (fluid) model for a direct current discharge used in a chemical vapor deposition system is developed. The model is built for a two-dimensional axisymmetric system and incorporates an electron energy balance for low-pressure Ar gas. The underlying physics of the fluid model is briefly discussed. The fluid and Poisson equations for plasma species are used as the model background. The plasma species considered in the model include electrons, Ar+ ions, and Ar atoms in ground and excited states. Nine reactions between these species are taken into account, including surface reactions. The densities of various plasma species as well as the relative contributions of generation and annihilation processes for electrons, ions, and atoms are calculated. The concentrations for electrons and Ar+ ions on the order of 1020 m-3 are obtained for the plasma in the computer simulations.

  11. Effect of process parameters on properties of argon–nitrogen plasma for titanium nitride film deposition

    SciTech Connect

    Saikia, Partha; Kakati, Bharat

    2013-11-15

    In this study, the effect of working pressure and input power on the physical properties and sputtering efficiencies of argon–nitrogen (Ar/N{sub 2}) plasma in direct current magnetron discharge is investigated. The discharge in Ar/N{sub 2} is used to deposit TiN films on high speed steel substrate. The physical plasma parameters are determined by using Langmuir probe and optical emission spectroscopy. On the basis of the different reactions in the gas phase, the variation of plasma parameters and sputtering rate are explained. A prominent change of electron temperature, electron density, ion density, and degree of ionization of Ar is found as a function of working pressure and input power. The results also show that increasing working pressure exerts a negative effect on film deposition rate while increasing input power has a positive impact on the same. To confirm the observed physical properties and evaluate the texture growth as a function of deposition parameters, x-ray diffraction study of deposited TiN films is also done.

  12. Diamondlike carbon deposition on plastic films by plasma source ion implantation

    NASA Astrophysics Data System (ADS)

    Tanaka, T.; Yoshida, M.; Shinohara, M.; Takagi, T.

    2002-05-01

    Application of pulsed high negative voltage (~10 μs pulse width, 300-900 pulses per second) to a substrate is found to induce discharge, thereby increasing ion current with an inductively coupled plasma source. This plasma source ion beam implantation (PSII) technique is investigated for the pretreatment and deposition of diamond-like carbon (DLC) thin layer on polyethylene terepthalate (PET) film. Pretreatment of PET with N2 and Ar plasma is expected to provide added barrier effects when coupled with DLC deposition, with possible application to fabrication of PET beverage bottles. PSII treatment using N2 and Ar in separate stages is found to change the color of the PET film, effectively increasing near-ultraviolet absorption. The effects of this pretreatment on the chemical bonding of C, H, and O are examined by x-ray photoelectron spectroscopy (XPS). DLC thin film was successfully deposited on the PET film. The surface of the DLC thin layer is observed to be smooth by scanning electron microscopy, and its structure characteristics are examined by XPS and laser Raman spectroscopy. Subsequent processing using acetylene or acetylene and Ar (20%) produced thin carbon layers that are confirmed to be graphite-dominated DLC. Also, this PSII method is employed in order to deposit the DLC layer on the inside surface of the PET bottle and to reduce oxygen permeation rate by 40%.

  13. Deposition of Fluorinated Diamond-Like-Carbon Films by Exposure of Electrothermal Pulsed Plasmas

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Iida, Masayasu

    2011-08-01

    Thin amorphous carbon films are deposited on silicon substrates by exposure to pulsed plasmas where the feed gas is mainly generated from the ablation of an insulator. An electrothermal pulsed plasma thruster with a discharge room in an insulator rod is used as the pulsed plasma for the ablation of the insulator, and the material of the insulator rod is poly(tetrafluoroethylene) (PTFE). The pulsed plasma, in which the estimated electron density is on the order of 1022-1023 m-3, is generated by the stored energy in the capacitor. The deposition rate, which depends on the stored energy, is lower than 1 nm per pulse in our experiment. The maximum hardness measured using a nanoindenter is about 7 GPa at a stored energy of about 2.7 J, beyond which the hardness of the films decreases with the increase in stored energy. Raman spectroscopy is also carried out to examine the formation of fluorinated diamond-like carbon films. In addition, the influence of dilution gas on the properties of the deposited films is also investigated.

  14. Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

    SciTech Connect

    Oliveira, M. H. Jr.; Viana, G. A.; Marques, F. C.; Lima, M. M. Jr. de; Cros, A.; Cantarero, A.

    2010-12-15

    Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH{sub 4}) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

  15. Hydrogen-dominated plasma, due to silane depletion, for microcrystalline silicon deposition

    SciTech Connect

    Howling, A. A.; Sobbia, R.; Hollenstein, Ch.

    2010-07-15

    Plasma conditions for microcrystalline silicon deposition generally require a high flux of atomic hydrogen, relative to SiH{sub {alpha}=0{yields}3} radicals, on the growing film. The necessary dominant partial pressure of hydrogen in the plasma is conventionally obtained by hydrogen dilution of silane in the inlet flow. However, a hydrogen-dominated plasma environment can also be obtained due to plasma depletion of the silane in the gas mixture, even up to the limit of pure silane inlet flow, provided that the silane depletion is strong enough. At first sight, it may seem surprising that the composition of a strongly depleted pure silane plasma consists principally of molecular hydrogen, without significant contribution from the partial pressure of silane radicals. The aim here is to bring some physical insight by means of a zero-dimensional, analytical plasma chemistry model. The model is appropriate for uniform large-area showerhead reactors, as shown by comparison with a three-dimensional numerical simulations. The SiH{sub {alpha}} densities remain very low because of their rapid diffusion and surface reactivity, contributing to film growth which is the desired scenario for efficient silane utilization. Significant SiH{sub {alpha}} densities due to poor design of reactor and gas flow, on the other hand, would result in powder formation wasting silane. Conversely, hydrogen atoms are not deposited, but recombine on the film surface and reappear as molecular hydrogen in the plasma. Therefore, in the limit of extremely high silane depletion fraction (>99.9%), the silane density falls below the low SiH{sub {alpha}} densities, but only the H radical can eventually reach significant concentrations in the hydrogen-dominated plasma.

  16. Plasma Enhanced Atomic Layer Deposition of Cooper Seed Layers at Low Process Temperatures

    NASA Astrophysics Data System (ADS)

    Mao, Jiajun

    In conventional Cu interconnect fabrication, a sputtered copper seed layer is deposited before the electrochemically deposited (ECD) copper plating step. However, as interconnect dimensions scale down, non-conformal seed layer growth and subsequent voiding of metallized structures is becoming a critical issue. With its established excellent thickness controllability and film conformality, atomic layer deposition (ALD) is becoming an attractive deposition approach for the sub-24nm fabrication regime. However, in order to achieve a smooth and continuous seed layer deposition, a low process temperature (below 100°C) is needed, given the tendency of Cu agglomeration at elevated temperature. In this research, plasma enhanced ALD (PEALD) Cu processes at low process temperature are developed using two novel precursors: Cuprum and AbaCus. The volatility and thermal stability of these two precursors are presented. Self-limiting nature of the PEALD processes are demonstrated. Key film properties including purity, resistivity, conformality, adhesion and platability are evaluated using multiple characterization techniques. In addition, film nucleation and growth of PEALD Cu at room temperature on different liner materials are studied. Via structures are employed for the investigation of film continuity on side walls. It is also shown that film conformality and platability can be improved by over saturating the plasma reactions.

  17. An Evaluation of Atmospheric-pressure Plasma for the Cost-Effective Deposition of Antireflection Coatings

    SciTech Connect

    Rob Sailer; Guruvenket Srinivasan; Kyle W. Johnson; Douglas L. Schulz

    2010-04-01

    Atmospheric-pressure plasma deposition (APPD) has previously been used to deposit various functional materials including polymeric surface modification layers, transparent conducting oxides, and photo catalytic materials. For many plasma polymerized coatings, reaction occurs via free radical mechanism where the high energy electrons from the plasma activate the olefinic carbon-carbon double bonds - a typical functional group in such precursors. The precursors for such systems are typically inexpensive and readily available and have been used in vacuum PECVD previously. The objectives are to investigate: (1) the effect of plasma power, gas composition and substrate temperature on the Si-based film properties using triethylsilane(TES) as the precursor; and (2) the chemical, mechanical, and optical properties of several experimental matrices based on Design of Experiment (DOE) principals. A simple APPD route has been utilized to deposit Si based films from an inexpensive precursor - Triethylsilane (TES). Preliminary results indicates formation of Si-C & Si-O and Si-O, Si-C & Si-N bonds with oxygen and nitrogen plasmas respectively. N{sub 2}-O{sub 2} plasma showed mixed trend; however oxygen remains a significant portion of all films, despite attempts to minimize exposure to atmosphere. SiN, SiC, and SiO ratios can be modified by the reaction conditions resulting in differing film properties. SE studies revealed that films with SiN bond possess refractive index higher than coatings with Si-O/Si-C bonds. Variable angle reflectance studies showed that SiOCN coatings offer AR properties; however thickness and refractive index optimization of these coatings remains necessary for application as potential AR coatings.

  18. Degradation of Gate Oxide Reliability due to Plasma-Deposited Silicon Nitride

    NASA Astrophysics Data System (ADS)

    Ogino, Masaaki; Sugahara, Yoshiyuki; Kuribayashi, Hitoshi; Yamabe, Kikuo

    2004-03-01

    The effects of plasma-enhanced chemical vapor deposition (PE-CVD) silicon nitride (p-SiN) passivation films on time dependent dielectric breakdown (TDDB) of gate oxide were studied. It was found that degradation of TDDB characteristics with p-SiN films was suppressed by the change in p-SiN deposition conditions. The correlation between trapped electron density and TDDB characteristics varied, depending on the p-SiN films. The degradation of TDDB characteristics was also enhanced with phosphosilicate glass (PSG) under the p-SiN passivation film.

  19. Growth and Characteristics of Freestanding Hemispherical Diamond Films by Microwave Plasma Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Wang, Qi-Liang; Lü, Xian-Yi; Li, Liu-An; Cheng, Shao-Heng; Li, Hong-Dong

    2010-04-01

    Freestanding hemispherical diamond films have been fabricated by microwave plasma chemical vapor deposition using graphite and molybdenum (Mo) as substrates. Characterized by Raman spectroscopy and scanning electron microscopy, the crystalline quality of the films deposited on Mo is higher than that on graphite, which is attributed to the difference in intrinsic properties of the two substrates. By decreasing the methane concentration, the diamond films grown on the Mo substrate vary from black to white, and the optical transparency is enhanced. After polishing the growth side, the diamond films show an infrared transmittance of 35-60% in the range 400-4000 cm-1.

  20. Plasma-assisted directed vapor deposition for synthesizing lithium phosphorus oxynitride thin films

    NASA Astrophysics Data System (ADS)

    Kim, Yoon Gu

    This dissertation explores a new vapor deposition route for synthesizing lithium phosphorus oxynitride (Lipon) thin-film electrolytes for rechargeable thin-film Li/Li-ion batteries. These batteries operate at a high voltage (around 4.0 V) and exhibit a long cyclic life (over 10,000 charge/discharge cycles). These features stem from the extremely low leakage current of the Lipon film electrolyte when in contact with a lithium anode, and its good Li-ion conductivity (in the 10-6-10-7 S/cm range). Lipon films have usually been synthesized by reactive RF-magnetron sputtering, which suffers from a very low deposition rate (˜2 nm/min). It therefore takes many hours to make the 1-2 mum thick films needed for battery applications. Other deposition approaches, such as Pulsed Laser Deposition, Ion Beam Assisted Deposition, and E-beam evaporation, have been investigated but resulted in unsatisfactory Lipon film performance. Here, a plasma-assisted directed vapor deposition (PA-DVD) approach has been explored to synthesize dense, amorphous Lipon films. Unlike conventional e-beam evaporation, the e-beam based DVD approach employs an annular nozzle to generate a rarefied supersonic inert gas jet around the periphery of an electron beam evaporated source material. The vapor is entrained in the jet and rapidly transferred to a substrate. Because the supersonic gas jet focuses the vapor (it impedes lateral spreading of the vapor flux), most of the evaporant reaches the substrate. As a result, the deposition rate of Lipon films can be potentially much higher than most other processes. The PA-DVD approach used here employs a hollow cathode to create low-energy plasma through which the vapor is propagated. This plasma ionized some of the evaporant and reactive gases (nitrogen) that were added to the jet. This increased their reactivity and atomic mobility on a substrate enabling the reactive synthesis of lithium phosphorus oxynitride from a lithium phosphate source. This dissertation

  1. Deposition of Lanthanum Strontium Cobalt Ferrite (LSCF) Using Suspension Plasma Spraying for Oxygen Transport Membrane Applications

    NASA Astrophysics Data System (ADS)

    Fan, E. S. C.; Kesler, O.

    2015-08-01

    Suspension plasma spray deposition was utilized to fabricate dense lanthanum strontium cobalt ferrite oxygen separation membranes (OSMs) on porous metal substrates for mechanical support. The as-sprayed membranes had negligible and/or reversible material decomposition. At the longer stand-off distance (80 mm), smooth and dense membranes could be manufactured using a plasma with power below approximately 81 kW. Moreover, a membrane of 55 μm was observed to have very low gas leakage rates desirable for OSM applications. This thickness could potentially be decreased further to improve oxygen diffusion by using metal substrates with finer surface pores.

  2. Deposition of carbonic films from plasma of arc discharge without a cathode spot

    NASA Astrophysics Data System (ADS)

    Gasanov, I.; Gurbanov, I.

    2003-09-01

    PVD ways of synthesis of hydrogen-free diamond-like films with high speed of a deposition of particles are analyzed. The technique of obtaining of coatings by means of a vacuum - arc discharge and of a plasma-optical filter provide the highest characteristics of -C amorphous diamond. However, the given way of synthesis is unwieldy and requires considerable costs. The capability of creation of the reactor of carbonic plasma in discharge with electron-beam heating of the cathode is consider. The control of power, entered into the graphitic cathode, allows essentially to limit a dispersion of an evaporated material.

  3. TOPICAL REVIEW: A review of plasma enhanced chemical vapour deposition of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Meyyappan, M.

    2009-11-01

    Plasma enhanced chemical vapour deposition (PECVD) has been widely discussed in the literature for the growth of carbon nanotubes (CNTs) and carbon nanofibres (CNFs) in recent years. Advantages claimed include lower growth temperatures relative to thermal CVD and the ability to grow individual, free-standing, vertical CNFs instead of tower-like structures or ensembles. This paper reviews the current status of the technology including equipment, plasma chemistry, diagnostics and modelling, and mechanisms. Recent accomplishments include PECVD of single-walled CNTs and growth at low temperatures for handling delicate substrates such as glass.

  4. Single crystal chemical vapor deposit diamond detector for energetic plasma measurement in space

    NASA Astrophysics Data System (ADS)

    Ogasawara, K.; Broiles, T. W.; Coulter, K. E.; Dayeh, M. A.; Desai, M. I.; Livi, S. A.; McComas, D. J.; Walther, B. C.

    2015-03-01

    This study reports the performance of single crystal chemical vapor deposit diamond detectors for measuring space plasma and energetic particles: ~7 keV energy resolution for protons with a 14 keV threshold level, and good response linearity for ions and electrons as expected from Monte-Carlo calculations of primary particle energy loss. We investigated that these diamond detectors are able to operate at high temperature (> 70 ° C) and have fast response times (< 1 ns rise time). While silicon detectors have proven capability over this energy range for space plasma measurements, diamond detectors offer a faster response, higher temperature operation, greater radiation tolerance, and immunity to light.

  5. Influence of argon plasma on the deposition of Al2O3 film onto the PET surfaces by atomic layer deposition

    PubMed Central

    2013-01-01

    In this paper, polyethyleneterephthalate (PET) films with and without plasma pretreatment were modified by atomic layer deposition (ALD) and plasma-assisted atomic layer deposition (PA-ALD). It demonstrates that the Al2O3 films are successfully deposited onto the surface of PET films. The cracks formed on the deposited Al2O3 films in the ALD, plasma pretreated ALD, and PA-ALD were attributed to the energetic ion bombardment in plasmas. The surface wettability in terms of water contact angle shows that the deposited Al2O3 layer can enhance the wetting property of modified PET surface. Further characterizations of the Al2O3 films suggest that the elevated density of hydroxyl -OH group improve the initial growth of ALD deposition. Chemical composition of the Al2O3-coated PET film was characterized by X-ray photoelectron spectroscopy, which shows that the content of C 1s reduces with the growing of O 1s in the Al2O3-coated PET films, and the introduction of plasma in the ALD process helps the normal growth of Al2O3 on PET in PA-ALD. PMID:23413804

  6. Nanofabrication using home-made RF plasma coupled chemical vapour deposition system

    NASA Astrophysics Data System (ADS)

    Ong, Si Ci; Ilyas, Usman; Rawat, Rajdeep Singh

    2014-08-01

    Zinc oxide, ZnO, a popular semiconductor material with a wide band gap (3.37 eV) and high binding energy of the exciton (60 meV), has numerous applications such as in optoelectronics, chemical/biological sensors, and drug delivery. This project aims to (i) optimize the operating conditions for growth of ZnO nanostructures using the chemical vapor deposition (CVD) method, and (ii) investigate the effects of coupling radiofrequency (RF) plasma to the CVD method on the quality of ZnO nanostructures. First, ZnO nanowires were synthesized using a home-made reaction setup on gold-coated and non-coated Si (100) substrates at 950 °C. XRD, SEM, EDX, and PL measurements were used for characterizations and it was found that a deposition duration of 10 minutes produced the most well-defined ZnO nanowires. SEM analysis revealed that the nanowires had diameters ranging from 30-100 mm and lengths ranging from 1-4 µm. In addition, PL analysis showed strong UV emission at 380 nm, making it suitable for UV lasing. Next, RF plasma was introduced for 30 minutes. Both remote and in situ RF plasma produced less satisfactory ZnO nanostructures with poorer crystalline structure, surface morphology, and optical properties due to etching effect of energetic ions produced from plasma. However, a reduction in plasma discharge duration to 10 minutes produced thicker and shorter ZnO nanostructures. Based on experimentation conducted, it is insufficient to conclude that RF plasma cannot aid in producing well-defined ZnO nanostructures. It can be deduced that the etching effect of energetic ions outweighed the increased oxygen radical production in RF plasma nanofabrication.

  7. Status of Plasma Physics Techniques for the Deposition of Tribological Coatings

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1984-01-01

    The plasma physics deposition techniques of sputtering and ion-plating are reviewed. Their characteristics and potentials are discussed in terms of synthesis or deposition of tribological coatings. Since the glow discharge or plasma generated in the conventional sputtering and ion-plating techniques has a low ionization efficiency, rapid advances have been made in equipment design to further increase the ionization efficiency. The enhanced ionization favorably affects the nucleation and growth sequence of the coating. This leads to improved adherence and coherence, higher density, favorable morphological growth, and reduced internal stresses in the coatings. As a result, desirable coating characteristics can be precision tailored. Tribological coating characteristics of sputtered solid film lubricants such as MoS2, ion-plated soft gold and lead metallic films, and sputtered and ion-plated wear-resistant refractory compound films such as nitrides and carbides are discussed.

  8. Development of dielectric barrier discharge plasma processing apparatus for mass spectrometry and thin film deposition.

    PubMed

    Majumdar, Abhijit; Hippler, Rainer

    2007-07-01

    Cost effective and a very simple dielectric barrier discharge plasma processing apparatus for thin film deposition and mass spectroscopic analysis of organic gas mixture has been described. The interesting features of the apparatus are the construction of the dielectric electrodes made of aluminum oxide or alumina (Al(2)O(3)) and glass and the generation of high ignition voltage from the spark plug transformer taken from car. Metal capacitor is introduced in between ground and oscilloscope to measure the executing power during the discharge and the average electron density in the plasma region. The organic polymer films have been deposited on Si (100) substrate using several organic gas compositions. The experimental setup provides a unique drainage system from the reaction chamber controlled by a membrane pump to suck out and remove the poisonous gases or residuals (cyanogens, H-CN, CH(x)NH(2), etc.) which have been produced during the discharge of CH(4)N(2) mixture. PMID:17672789

  9. Growth of aligned carbon nanotubes on carbon microfibers by dc plasma-enhanced chemical vapor deposition

    SciTech Connect

    Chen, L H.; AuBuchon, J F.; Chen, I C.; Daraio, C; Ye, X R.; Gapin, A; Jin, Sungho; Wang, Chong M.

    2006-01-16

    It is shown that unidirectionally aligned carbon nanotubes can be grown on electrically conductive network of carbon microfibers via control of buffer layer material and applied electric field during dc plasma chemical vapor deposition growth. Ni catalyst deposition on carbon microfiber produces relatively poorly aligned nanotubes with significantly varying diameters and lengths obtained. The insertion of Ti 5 nm thick underlayer between Ni catalyst layer and C microfiber substrate significantly alters the morphology of nanotubes, resulting in much better aligned, finer diameter, and longer array of nanotubes. This beneficial effect is attributed to the reduced reaction between Ni and carbon paper, as well as prevention of plasma etching of carbon paper by inserting a Ti buffer layer. Such a unidirectionally aligned nanotube structure on an open-pore conductive substrate structure may conveniently be utilized as a high-surface-area base electrodes for fuel cells, batteries, and other electrochemical and catalytic reactions.

  10. Characterization of TiO x film prepared by plasma enhanced chemical vapor deposition using a multi-jet hollow cathode plasma source

    NASA Astrophysics Data System (ADS)

    Nakamura, Masatoshi; Korzec, Dariusz; Aoki, Toru; Engemann, Jurgen; Hatanaka, Yoshinori

    2001-05-01

    The high rate deposition of TiO x film at low temperature was achieved by plasma enhanced chemical vapor deposition (PECVD) using titanium tetraisopropoxide (TTIP) as a source material. The multi-jet hollow cathode plasma source was used to generate the high-density plasma, which was showered toward the substrate. The emission spectra suggest that oxygen radicals play an important role for dissociation of the source material and for yielding the precursors. The high deposition rate up to 50 nm/min was achieved by this process. The as-deposited films are completely amorphous. They consist of structures with complex bondings including both tetrahedral and octahedral components. Though they have such complex bondings, the hydrophilicity of the PECVD film is excellent comparing to that of the annealed crystalline anatase structure. It seems that the PECVD using the multi-jet plasma source is promising for fabrication of hydrophilic TiO x films in low-temperature process.

  11. Deposition and characterization of molybdenum thin films using dc-plasma magnetron sputtering

    SciTech Connect

    Khan, Majid; Islam, Mohammad

    2013-12-15

    Molebdenum (Mo) thin films were deposited on well-cleaned soda-lime glass substrates using DC-plasma magnetron sputtering. In the design of experiment deposition was optimized for maximum beneficial characteristics by monitoring effect of process variables such as deposition power (100–200 W). Their electrical, structural and morphological properties were analyzed to study the effect of these variables. The electrical resistivity of Mo thin films could be reduced by increasing deposition power. Within the range of analyzed deposition power, Mo thin films showed a mono crystalline nature and the crystallites were found to have an orientation along [110] direction. The surface morphology of thin films showed that a highly dense micro structure has been obtained. The surface roughness of films increased with deposition power. The adhesion of Mo thin films could be improved by increasing the deposition power. Atomic force microscopy was used for the topographical study of the films and to determine the roughness of the films. X-ray diffractrometer and scanning electron microscopy analysis were used to investigate the crystallinity and surface morphology of the films. Hall effect measurement system was used to find resistivity, carrier mobility and carrier density of deposited films. The adhesion test was performed using scotch hatch tape adhesion test. Mo thin films prepared at deposition power of 200 W, substrate temperature of 23°C and Ar pressure of 0.0123 mbar exhibited a mono crystalline structure with an orientation along (110) direction, thickness of ∼550 nm and electrical resistivity value of 0.57 × 10{sup −4} Ω cm.

  12. Improved film quality of plasma enhanced atomic layer deposition SiO{sub 2} using plasma treatment cycle

    SciTech Connect

    Kim, Haiwon; Chung, Ilsub; Kim, Seokyun; Shin, Seungwoo; Jung, Wooduck; Hwang, Ryong; Jeong, Choonsik; Hwang, Hanna

    2015-01-15

    Chemical, physical, and electrical characteristics of high quality silicon dioxide (SiO{sub 2}) films grown using low temperature plasma enhanced atomic layer deposition (PE-ALD) have been investigated as a buffer layer for three dimensional vertical NAND flash memory devices. The comparative angle resolved x-ray photoelectron spectroscopy studies show the plasma treatment cycle causes to shift the core level binding energy (chemical shifts) in the SiO{sub 2} film. The wet etch rates with respect to plasma treatment cycle times were varied due to curing of the SiO{sub 2} network defects by Ar{sup +} ions and oxygen radicals. It is assumed that the angle between the bonds linking SiO{sub 4} tetrahedra is a critical point understanding the variation in wet etch rate of SiO{sub 2}. The features of wet etch rate of low temperature high quality SiO{sub 2} demonstrated lower than high temperature low-pressure chemical vapor deposition (LP-CVD) SiO{sub 2} values. In addition, the better step-coverage compared to that of the LP-CVD SiO{sub 2} film was achieved from the deep trench structure having the 20:1 aspect ratio. PE-ALD SiO{sub 2} with plasma treatment cycle showed excellent I–V properties with higher breakdown voltage compared to LP-CVD SiO{sub 2} and similar to the thermal SiO{sub 2} carrier transport plot.

  13. Nanotransfer Printing Using Plasma Etched Silicon Stamps and Mediated by In-Situ Deposited Fluoropolyme

    SciTech Connect

    Bhandari, Deepak; Kravchenko, Ivan I; Lavrik, Nickolay V; Sepaniak, Michael J

    2011-01-01

    This communication describes a simple method that uses a thin film of octafluorocyclobutane (OFCB) polymer for efficient nanoscale transfer printing (nTP). Plasma polymerization of OFCB produces a Teflon-like fluoropolymer which strongly adheres and conformally covers 3-D inorganic stamp. The inherently low surface energy of in-situ deposited OFCB polymer on nanoscale silicon features is demonstrated as a unique nanocomposite stamp to fabricate various test structures with improved nTP feature resolution down to sub 100 nm.

  14. Controlling Degree of Crystalline Boron Carbide by Plasma Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Sandstrom, Joseph

    2007-03-01

    There has been a recent resurgence in the interest of semiconducting boron carbide, based on its use as a radiation hard semiconductor. Here, we present growth character and commensurate structural and electronic properties from the low temperature but large area (6" wafer) deposition of boron carbide from the solid source precursor, 1,2 - dicarbadodecaborane. Of special interest is the control over the degree of crystallinity as provided from changing plasma pressure growth.

  15. Microstructure of boron nitride coated on nuclear fuels by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Durmazuçar, Hasan H.; Gündüz, Güngör; Toker, Canan

    1998-08-01

    Three nuclear fuels, pure urania, 5% and 10% gadolinia containing fuels were coated with boron nitride to improve nuclear and physical properties. Coating was done by plasma enhanced chemical vapor deposition technique by using boron trichloride and ammonia. The specimens were examined under a scanning electron microscope. Boron nitride formed a grainy structure on all fuels. Gadolinia decreased the grain size of boron nitride. The fractal dimensions of fragmentation and of area-perimeter relation were determined.

  16. Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

    NASA Astrophysics Data System (ADS)

    Fleetwood, James D.

    Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these processes, while compositional control is achieved with dissolved dopant compounds that are incorporated into the coating during deposition. In the work reported, sub-micron 8 mole % Y2O3-ZrO2 (YSZ) and gadolinia-doped ceria (GDC), powders, including those in suspension with scandium-nitrate dopants, were deposited on NiO-YSZ anodes, via very low pressure suspension plasma spray (VLPSPS) at Sandia National Laboratories' Thermal Spray Research Laboratory and electrophoretic deposition (EPD) at Purdue University. Plasma spray was carried out in a chamber held at 320 - 1300 Pa, with the plasma composed of argon, hydrogen, and helium. EPD was characterized utilizing constant current deposition at 10 mm electrode separation, with deposits sintered from 1300 -- 1500 °C for 2 hours. The role of suspension constituents in EPD was analyzed based on a parametric study of powder loading, powder specific surface area, polyvinyl butyral (PVB) content, polyethyleneimine (PEI) content, and acetic acid content. Increasing PVB content and reduction of particle specific surface area were found to eliminate the formation of cracks when drying. PEI and acetic acid content were used to control suspension stability and the adhesion of deposits. Additionally, EPD was used to fabricate YSZ/GDC bilayer electrolyte systems. The resultant YSZ electrolytes were 2-27 microns thick and up to 97% dense. Electrolyte performance as part of a SOFC system with screen printed LSCF cathodes was evaluated with peak

  17. Initiation of atomic layer deposition of metal oxides on polymer substrates by water plasma pretreatment

    SciTech Connect

    Steven Brandt, E.; Grace, Jeremy M.

    2012-01-15

    The role of surface hydroxyl content in atomic layer deposition (ALD) of aluminum oxide (AO) on polymers is demonstrated by performing an atomic layer deposition of AO onto a variety of polymer types, before and after pretreatment in a plasma struck in water vapor. The treatment and deposition reactions are performed in situ in a high vacuum chamber that is interfaced to an x-ray photoelectron spectrometer to prevent adventitious exposure to atmospheric contaminants. X-ray photoelectron spectroscopy is used to follow the surface chemistries of the polymers, including theformation of surface hydroxyls and subsequent growth of AO by ALD. Using dimethyl aluminum isopropoxide and water as reactants, ALD is obtained for water-plasma-treated poly(styrene) (PS), poly(propylene) (PP), poly(vinyl alcohol) (PVA), and poly(ethylene naphthalate) (PEN). For PS, PP, and PEN, initial growth rates of AO on the native (untreated) polymers are at least an order of magnitude lower than on the same polymer surface following the plasma treatment. By contrast, native PVA is shown to initiate ALD of AO as a result of the presence of intrinsic surface hydroxyls that are derived from the repeat unit of this polymer.

  18. Surface Passivation of ZrO2 Artificial Dentures by Magnetized Coaxial Plasma deposition

    NASA Astrophysics Data System (ADS)

    Arai, Soya; Kurumi, Satoshi; Matsuda, Ken-Ichi; Suzuki, Kaoru; Hara, Katsuya; Kato, Tatsuya; Asai, Tomohiko; Hirose, Hideharu; Masutani, Shigeyuki; Nihon University Team

    2015-09-01

    Recent growth and fabrication technologies for functional materials have been greatly contributed to drastic development of oral surgery field. Zirconia based ceramics is expected to utilize artificial dentures because these ceramics have good biocompatibility, high hardness and aesthetic attractively. However, to apply these ceramics to artificial dentures, this denture is removed from a dental plate because of weakly bond. For improving this problem, synthesis an Al passivation-layer on the ceramics for bonding with these dental items is suitable. In order to deposit the passivation layer, we focused on a magnetized coaxial plasma deposition (MCPD). The greatest characteristic of MCPD is that high-melting point metal can be deposited on various substrates. Additionally, adhesion force between substrate and films deposited by the MCPD is superior to it of general deposition methods. In this study, we have reported on the growth techniques of Al films on ZrO2 for contributing to oral surgery by the MCPD. Surface of deposited films shows there were some droplets and thickness of it is about 200 nm. Thickness is increased to 500 nm with increasing applied voltage.

  19. The evolution of carbon nanotubes during their growth by plasma enhanced chemical vapor deposition.

    PubMed

    Wang, Hengzhi; Ren, Z F

    2011-10-01

    During the growth of carbon nanotubes (CNTs) by plasma enhanced chemical vapor deposition (PECVD), plasma etching is the crucial factor that determines the growth mode and alignment of the CNTs. Focusing on a thin catalyst coating (Ni = 5 nm), this study finds that the CNT growth by PECVD goes through three stages from randomly entangled (I-CNTs) to partially aligned (II-CNTs) to fully aligned (III-CNTs). The I-CNTs and II-CNTs are mostly etched away by the plasma as time goes by ending up with III-CNTs as the only product when growth time is long enough. However, with a thickness of the catalyst coating of 10 nm or more, neither I-CNTs nor II-CNTs are produced, but III-CNTs are the only type of CNTs grown during the whole growth process. During the growth of III-CNTs, the catalyst particles (Ni) stay on the tips of each of the aligned CNTs and act as a 'safety helmet' to protect the CNTs from plasma ion bombardment. On the other hand, it is also the plasma that limits the growth of III-CNTs, since the plasma eventually etches all the catalytic particles out and stops the growth. PMID:21911923

  20. The evolution of carbon nanotubes during their growth by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Wang, Hengzhi; Ren, Z. F.

    2011-10-01

    During the growth of carbon nanotubes (CNTs) by plasma enhanced chemical vapor deposition (PECVD), plasma etching is the crucial factor that determines the growth mode and alignment of the CNTs. Focusing on a thin catalyst coating (Ni = 5 nm), this study finds that the CNT growth by PECVD goes through three stages from randomly entangled (I-CNTs) to partially aligned (II-CNTs) to fully aligned (III-CNTs). The I-CNTs and II-CNTs are mostly etched away by the plasma as time goes by ending up with III-CNTs as the only product when growth time is long enough. However, with a thickness of the catalyst coating of 10 nm or more, neither I-CNTs nor II-CNTs are produced, but III-CNTs are the only type of CNTs grown during the whole growth process. During the growth of III-CNTs, the catalyst particles (Ni) stay on the tips of each of the aligned CNTs and act as a 'safety helmet' to protect the CNTs from plasma ion bombardment. On the other hand, it is also the plasma that limits the growth of III-CNTs, since the plasma eventually etches all the catalytic particles out and stops the growth.

  1. Growth of cubic boron nitride on diamond particles by microwave plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Saitoh, H.; Yarbrough, W. A.

    1991-06-01

    The nucleation and growth of cubic boron nitride (c-BN) onto diamond powder using solid NaBH4 in low pressure gas mixtures of NH3 and H2 by microwave plasma enhanced chemical vapor deposition has been studied. Boron nitride was deposited on submicron diamond seed crystals scattered on (100) silicon single crystal wafers and evidence was found for the formation of the cubic phase. Diamond powder surfaces appear to preferentially nucleate c-BN. In addition, it was found that the ratio of c-BN to turbostratic structure boron nitride (t-BN) deposited increases with decreasing NH3 concentration in H2. It is suggested that this may be due to an increased etching rate for t-BN by atomic hydrogen whose partial pressure may vary with NH3 concentration.

  2. Plasma-enhanced-chemical-vapor-deposited ultralow k for a postintegration porogen removal approach

    SciTech Connect

    Jousseaume, V.; Favennec, L.; Zenasni, A.; Passemard, G.

    2006-05-01

    Conventional Cu-ultra low K (ULK) integration schemes lead to a drastic increase of the effective dielectric constant due to porous material degradation during process steps. Although a postintegration porogen removal scheme allows overcoming these issues, only spin-on dielectrics were developed to validate this approach. In this letter, plasma-enhanced chemical-vapor deposition is used to deposit ULK dielectric (k<2.5). The precursor chemistry and the deposition conditions have been chosen to obtain a material with the required characteristics to use a postintegration porogen removal approach: porogen thermal stability up to 325 deg. C, good mechanical properties of the hybrid film, no metallic barrier diffusion in the film, and a minimal shrinkage after the porogen removal treatment.

  3. Metal-free plasma-enhanced chemical vapor deposition of large area nanocrystalline graphene

    NASA Astrophysics Data System (ADS)

    Schmidt, Marek E.; Xu, Cigang; Cooke, Mike; Mizuta, Hiroshi; Chong, Harold M. H.

    2014-04-01

    This paper reports on large area, metal-free deposition of nanocrystalline graphene (NCG) directly onto wet thermally oxidized 150 mm silicon substrates using parallel-plate plasma-enhanced chemical vapor deposition. Thickness non-uniformities as low as 13% are achieved over the whole substrate. The cluster size {{L}_{\\text{a}}} of the as-obtained films is determined from Raman spectra and lies between 1.74 and 2.67 nm. The film uniformity was further confirmed by Raman mapping. The sheet resistance {{R}_{\\text{sq}}} of 3.73 \\text{k}\\Omega and charge carrier mobility μ of 2.49\\;\\text{c}{{\\text{m}}^{2}}\\;{{\\text{V}}^{-1}}\\;{{\\text{s}}^{-1}} are measured. We show that the NCG films can be readily patterned by reactive ion etching. NCG is also successfully deposited onto quartz and sapphire substrates and showed >85% optical transparency in the visible light spectrum.

  4. Atmospheric pressure plasma deposition of antimicrobial coatings on non-woven textiles

    NASA Astrophysics Data System (ADS)

    Nikiforov, Anton Yu.; Deng, Xiaolong; Onyshchenko, Iuliia; Vujosevic, Danijela; Vuksanovic, Vineta; Cvelbar, Uros; De Geyter, Nathalie; Morent, Rino; Leys, Christophe

    2016-08-01

    A simple method for preparation of nanoparticle incorporated non-woven fabric with high antibacterial efficiency has been proposed based on atmospheric pressure plasma process. In this work direct current plasma jet stabilized by fast nitrogen flow was used as a plasma deposition source. Three different types of the nanoparticles (silver, copper and zinc oxide nanoparticles) were employed as antimicrobial agents. X-ray photoelectron spectroscopy (XPS) measurements have shown a positive chemical shift observed for Ag 3d 5/2 (at 368.1 eV) suggests that silver nanoparticles (AgNPs) are partly oxidized during the deposition. The surface chemistry and the antibacterial activity of the samples against Staphylococcus aureus and Escherichia coli were investigated and analyzed. It is shown that the samples loaded with nanoparticles of Ag and Cu and having the barrier layer of 10 nm characterized by almost 97% of bacterial reduction whereas the samples with ZnO nanoparticles provide 86% reduction of Staphylococcus aureus. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  5. Fourth-generation plasma immersion ion implantation and deposition facility for hybrid surface modification layer fabrication.

    PubMed

    Wang, Langping; Huang, Lei; Xie, Zhiwen; Wang, Xiaofeng; Tang, Baoyin

    2008-02-01

    The fourth-generation plasma immersion ion implantation and deposition (PIIID) facility for hybrid and batch treatment was built in our laboratory recently. Comparing with our previous PIIID facilities, several novel designs are utilized. Two multicathode pulsed cathodic arc plasma sources are fixed on the chamber wall symmetrically, which can increase the steady working time from 6 h (the single cathode source in our previous facilities) to about 18 h. Meanwhile, the inner diameter of the pulsed cathodic arc plasma source is increased from the previous 80 to 209 mm, thus, large area metal plasma can be obtained by the source. Instead of the simple sample holder in our previous facility, a complex revolution-rotation sample holder composed of 24 shafts, which can rotate around its axis and adjust its position through revolving around the center axis of the vacuum chamber, is fixed in the center of the vacuum chamber. In addition, one magnetron sputtering source is set on the chamber wall instead of the top cover in the previous facility. Because of the above characteristic, the PIIID hybrid process involving ion implantation, vacuum arc, and magnetron sputtering deposition can be acquired without breaking vacuum. In addition, the PIIID batch treatment of cylinderlike components can be finished by installing these components on the rotating shafts on the sample holder. PMID:18315292

  6. Fourth-generation plasma immersion ion implantation and deposition facility for hybrid surface modification layer fabrication

    SciTech Connect

    Wang Langping; Huang Lei; Xie Zhiwen; Wang Xiaofeng; Tang Baoyin

    2008-02-15

    The fourth-generation plasma immersion ion implantation and deposition (PIIID) facility for hybrid and batch treatment was built in our laboratory recently. Comparing with our previous PIIID facilities, several novel designs are utilized. Two multicathode pulsed cathodic arc plasma sources are fixed on the chamber wall symmetrically, which can increase the steady working time from 6 h (the single cathode source in our previous facilities) to about 18 h. Meanwhile, the inner diameter of the pulsed cathodic arc plasma source is increased from the previous 80 to 209 mm, thus, large area metal plasma can be obtained by the source. Instead of the simple sample holder in our previous facility, a complex revolution-rotation sample holder composed of 24 shafts, which can rotate around its axis and adjust its position through revolving around the center axis of the vacuum chamber, is fixed in the center of the vacuum chamber. In addition, one magnetron sputtering source is set on the chamber wall instead of the top cover in the previous facility. Because of the above characteristic, the PIIID hybrid process involving ion implantation, vacuum arc, and magnetron sputtering deposition can be acquired without breaking vacuum. In addition, the PIIID batch treatment of cylinderlike components can be finished by installing these components on the rotating shafts on the sample holder.

  7. Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

    SciTech Connect

    Demaurex, Bénédicte Bartlome, Richard; Seif, Johannes P.; Geissbühler, Jonas; Ballif, Christophe; De Wolf, Stefaan; Alexander, Duncan T. L.; Jeangros, Quentin

    2014-08-07

    Low-temperature (≤200 °C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-enhanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems not only from the growth conditions but also from unintentional contamination of the reactor. Based on our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.

  8. One-step synthesis of chlorinated graphene by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Fan, Liwei; Zhang, Hui; Zhang, Pingping; Sun, Xuhui

    2015-08-01

    We developed an approach to synthesize the chlorinated single layer graphene (Cl-G) by one-step plasma enhanced chemical vapor deposition. Copper foil was simply treated with hydrochloric acid and then CuCl2 formed on the surface was used as Cl source under the assistance of plasma treatment. Compared with other two-step methods by post plasma/photochemical treatment of CVD-grown single layer graphene (SLG), one-step Cl-G synthesis approach is quite straightforward and effective. X-ray photoelectron spectroscopy (XPS) revealed that ∼2.45 atom% Cl remained in SLG. Compared with the pristine SLG, the obvious blue shifts of G band and 2D band along with the appearance of D' band and D + G band in the Raman spectra indicate p-type doping of Cl-G.

  9. Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

    SciTech Connect

    Demaurex, Bénédicte; Bartlome, Richard; Seif, Johannes P.; Geissbühler, Jonas; Alexander, Duncan T. L.; Jeangros, Quentin; Ballif, Christophe; De Wolf, Stefaan

    2014-08-05

    Low-temperature (≤ 180 °C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-ehanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems not only from the growth conditions but also from unintentional contamination of the reactor. As a result of our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.

  10. Fabrication and Characterization of Thermoresponsive Films Deposited by an RF Plasma Reactor

    PubMed Central

    Lucero, Adrianne E.; Reed, Jamie A.; Wu, Xiaomei; Canavan, Heather E.

    2014-01-01

    Summary Poly(N-isopropyl acrylamide) (pNIPAM) undergoes a sharp property change in response to a moderate thermal stimulus at physiological temperatures. In this work, we constructed a radio frequency (RF) plasma reactor for the plasma polymerization of pNIPAM. RF deposition is a method that coats surfaces of any geometry producing surfaces that are sterile and uniform, making this technique useful for forming biocompatible films. The films generated are characterized using X-ray photoelectron spectroscopy (XPS), contact angles, cell culture, and interferometry. We find that a plasma with a decreasing series of power settings (i.e., from 100W to 1W) at a pressure of 140 millitorr yields the most favorable results. PMID:24634643

  11. TiN Deposition and Process Diagnostics using Remote Plasma Sputtering

    NASA Astrophysics Data System (ADS)

    Yang, Wonkyun; Kim, Gi-Taek; Lee, Seunghun; Kim, Do-Geun; Kim, Jong-Kuk

    2013-08-01

    The discharge voltage-current characteristics and the optical diagnostics of a remote plasma sputtering system called by high density plasma assisted sputtering source (HiPASS) were investigated. The remote plasma was generated by the hollow cathode discharge (HCD) gun and was transported to the target surface by external electromagnet coils. This showed a wide process window because the sputtering voltage and current could be individually controlled. The ion density and energy distribution could be also controlled unlike the conventional magnetron sputtering. Titanium nitride films were deposited under different sputtering voltage. The high voltage mode induced the high ionization ratio of the sputtered atoms and the high ion energy toward the substrate. That resulted in the enlarged grain size, and the preferred orientation toward (220). Eventually, this optimized condition of HiPASS obtained the best hardness of TiN films to be about 48 GPa at the sputtering voltage of -800 V.

  12. Fabrication and Characterization of Thermoresponsive Films Deposited by an RF Plasma Reactor.

    PubMed

    Lucero, Adrianne E; Reed, Jamie A; Wu, Xiaomei; Canavan, Heather E

    2010-12-20

    Poly(N-isopropyl acrylamide) (pNIPAM) undergoes a sharp property change in response to a moderate thermal stimulus at physiological temperatures. In this work, we constructed a radio frequency (RF) plasma reactor for the plasma polymerization of pNIPAM. RF deposition is a method that coats surfaces of any geometry producing surfaces that are sterile and uniform, making this technique useful for forming biocompatible films. The films generated are characterized using X-ray photoelectron spectroscopy (XPS), contact angles, cell culture, and interferometry. We find that a plasma with a decreasing series of power settings (i.e., from 100W to 1W) at a pressure of 140 millitorr yields the most favorable results. PMID:24634643

  13. Free-standing thin film Ge single crystals grown by plasma-enhanced chemical vapor deposition

    NASA Technical Reports Server (NTRS)

    Outlaw, R. A.; Hopson, P., Jr.

    1984-01-01

    The films, which are approximately 10 microns in thickness, are grown epitaxially on polished (100) NaCl substrates at 450 C by plasma enhanced chemical vapor deposition. Upon cooling, the films are separated from the substrate by differential shear stress, leaving free-standing films of Ge which can be handled. Growths are attained by nucleating at minimum plasma power for very brief intervals and then raising the power to 65 W to increase the growth rate to approximately 10 microns/h. It is found that substrate exposure to the plasma at too high a power for too long a time sputters and erodes the surface, thereby substantially degrading the nucleation process and the ultimate growths. It is noted that the free-standing films are visually specular and exhibit a high degree of crystalline order when examined by X-ray diffraction. Auger electron spectroscopy and energy dispersive analysis of X-rays reveal no detectable bulk contamination.

  14. Characteristics of nanocomposite ZrO2/Al2O3 films deposited by plasma-enhanced atomic layer deposition.

    PubMed

    Yun, Sun Jin; Lim, Jung Wook; Kim, Hyun-Tak

    2007-11-01

    Nanocomposite ZrO2/Al2O3 (ZAO) films were deposited on Si by plasma-enhanced atomic layer deposition and the film characteristics including interfacial oxide formation, dielectric constant (k), and electrical breakdown strength were investigated without post-annealing process. In both the mixed and nano-laminated ZAO films, the thickness of the interfacial oxide layer (T(IL)) was considerably reduced compared to ZrO2 and Al2O3 films. The T(IL) was 0.8 nm in nano-composite films prepared at a mixing ratio (ZrO2:Al2O3) of 1:1. The breakdown strength and the leakage current level were greatly improved by adding Al2O3 as little as 7.9% compared to that of ZrO2 and were enhanced more with increasing content of Al2O3. The k of ZrO2 and mixed ZAO (Al2O3 7.9%) films were 20.0 and 16.5, respectively. These results indicate that the addition of Al2O3 to ZrO2 greatly improves the electrical properties with less cost of k compared to the addition of SiO2. PMID:18047146

  15. Plasma etch characteristics of aluminum nitride mask layers grown by low-temperature plasma enhanced atomic layer deposition in SF{sub 6} based plasmas

    SciTech Connect

    Perros, Alexander; Bosund, Markus; Sajavaara, Timo; Laitinen, Mikko; Sainiemi, Lauri; Huhtio, Teppo; Lipsanen, Harri

    2012-01-15

    The plasma etch characteristics of aluminum nitride (AlN) deposited by low-temperature, 200 deg. C, plasma enhanced atomic layer deposition (PEALD) was investigated for reactive ion etch (RIE) and inductively coupled plasma-reactive ion etch (ICP-RIE) systems using various mixtures of SF{sub 6} and O{sub 2} under different etch conditions. During RIE, the film exhibits good mask properties with etch rates below 10r nm/min. For ICP-RIE processes, the film exhibits exceptionally low etch rates in the subnanometer region with lower platen power. The AlN film's removal occurred through physical mechanisms; consequently, rf power and chamber pressure were the most significant parameters in PEALD AlN film removal because the film was inert to the SF{sub x}{sup +} and O{sup +} chemistries. The etch experiments showed the film to be a resilient masking material. This makes it an attractive candidate for use as an etch mask in demanding SF{sub 6} based plasma etch applications, such as through-wafer etching, or when oxide films are not suitable.

  16. Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films

    NASA Astrophysics Data System (ADS)

    Dimitrakellis, P.; Kalampounias, A. G.; Spiliopoulos, N.; Amanatides, E.; Mataras, D.; Lahootun, V.; Coeuret, F.; Madec, A.

    2016-07-01

    The effect of small disilane addition on the gas phase properties of silane-hydrogen plasmas and the microcrystalline silicon thin films growth is presented. The investigation was conducted in the high pressure regime and for constant power dissipation in the discharge with the support of plasma diagnostics, thin film studies and calculations of discharge microscopic parameters and gas dissociation rates. The experimental data and the calculations show a strong effect of disilane on the electrical properties of the discharge in the pressure window from 2 to 3 Torr that is followed by significant raise of the electron number density and the drop of the sheaths electric field intensity. Deposition rate measurements show an important four to six times increase even for disilane mole fractions as low as 0.3 %. The deposition rate enhancement was followed by a drop of the material crystalline volume fraction but films with crystallinity above 40 % were deposited with different combinations of total gas pressure, disilane and silane molar ratios. The enhancement was partly explained by the increase of the electron impact dissociation rate of silane which rises by 40% even for 0.1% disilane mole fraction. The calculations of the gas usage, the dissociation and the deposition efficiencies show that the beneficial effect on the growth rate is not just the result of the increase of Si-containing molecules density but significant changes on the species participating to the deposition and the mechanism of the film growth are caused by the disilane addition. The enhanced participation of the highly sticking to the surface radical such as disilylene, which is the main product of disilane dissociation, was considered as the most probable reason for the significant raise of the deposition efficiency. The catalytic effect of such type of radical on the surface reactivity of species with lower sticking probability is further discussed, while it is also used to explain the restricted

  17. Effect of Gas Sources on the Deposition of Nano-Crystalline Diamond Films Prepared by Microwave Plasma Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Weng, Jun; Xiong, Liwei; Wang, Jianhua; Man, Weidong; Chen, Guanhu

    2010-12-01

    Nano-crystalline diamond (NCD) films were deposited on silicon substrates by a microwave plasma enhanced chemical vapor deposition (MPCVD) reactor in C2H5OH/H2 and CH4/H2/O2 systems, respectively, with a constant ratio of carbon/hydrogen/oxygen. By means of atomic force microscopy (AFM) and X-ray diffraction (XRD), it was shown that the NCD films deposited in the C2H5OH/H2 system possesses more uniform surface than that deposited in the CH4/H2/O2 system. Results from micro-Raman spectroscopy revealed that the quality of the NCD films was different even though the plasmas in the two systems contain exactly the same proportion of elements. In order to explain this phenomenon, the bond energy of forming OH groups, energy distraction in plasma and the deposition process of NCD films were studied. The experimental results and discussion indicate that for a same ratio of carbon/hydrogen/oxygen, the C2H5OH/H2 plasma was beneficial to deposit high quality NCD films with smaller average grain size and lower surface roughness.

  18. Plasma-enhanced deposition of antifouling layers on silicone rubber surfaces

    NASA Astrophysics Data System (ADS)

    Jiang, Hongquan

    In food processing and medical environments, biofilms serve as potential sources of contamination, and lead to food spoilage, transmission of diseases or infections. Because of its ubiquitous and recalcitrant nature, Listeria monocytogenes biofilm is especially hard to control. Generating antimicrobial surfaces provide a method to control the bacterial attachment. The difficulty of silver deposition on polymeric surfaces has been overcome by using a unique two-step plasma-mediated method. First silicone rubber surfaces were plasma-functionalized to generate aldehyde groups. Then thin silver layers were deposited onto the functionalized surfaces according to Tollen's reaction. X-ray photoelectron spectroscopy (XPS), atomic force spectroscopy (AFM) and scanning electron microscopy (SEM) showed that silver particles were deposited. By exposing the silver coated surfaces to L. monocytogenes, it was demonstrated that they were bactericidal to L. monocytogenes. No viable bacteria were detected after 12 to 18 h on silver-coated silicone rubber surfaces. Another antifouling approach is to generate polyethylene glycol (PEG) thin layer instead of silver on polymer surfaces. Covalent bond of PEG structures of various molecular weights to cold-plasma-functionalized polymer surfaces, such as silicone rubber, opens up a novel way for the generation of PEG brush-like or PEG branch-like anti-fouling layers. In this study, plasma-generated surface free radicals can react efficiently with dichlorosilane right after plasma treatment. With the generation of halo-silane groups, this enables PEG molecules to be grafted onto the modified surfaces. XPS data clearly demonstrated the presence of PEG molecules on plasma-functionalized silicone rubber surfaces. AFM images showed the changed surface morphologies as a result of covalent attachment to the surface of PEG molecules. Biofilm experiment results suggest that the PEG brush-like films have the potential ability to be the next

  19. Plasma parameters of pulsed-dc discharges in methane used to deposit diamondlike carbon films

    NASA Astrophysics Data System (ADS)

    Corbella, C.; Rubio-Roy, M.; Bertran, E.; Andújar, J. L.

    2009-08-01

    Here we approximate the plasma kinetics responsible for diamondlike carbon (DLC) depositions that result from pulsed-dc discharges. The DLC films were deposited at room temperature by plasma-enhanced chemical vapor deposition (PECVD) in a methane (CH4) atmosphere at 10 Pa. We compared the plasma characteristics of asymmetric bipolar pulsed-dc discharges at 100 kHz to those produced by a radio frequency (rf) source. The electrical discharges were monitored by a computer-controlled Langmuir probe operating in time-resolved mode. The acquisition system provided the intensity-voltage (I-V) characteristics with a time resolution of 1 μs. This facilitated the discussion of the variation in plasma parameters within a pulse cycle as a function of the pulse waveform and the peak voltage. The electron distribution was clearly divided into high- and low-energy Maxwellian populations of electrons (a bi-Maxwellian population) at the beginning of the negative voltage region of the pulse. We ascribe this to intense stochastic heating due to the rapid advancing of the sheath edge. The hot population had an electron temperature Tehot of over 10 eV and an initial low density nehot which decreased to zero. Cold electrons of temperature Tecold˜1 eV represented the majority of each discharge. The density of cold electrons necold showed a monotonic increase over time within the negative pulse, peaking at almost 7×1010 cm-3, corresponding to the cooling of the hot electrons. The plasma potential Vp of ˜30 V underwent a smooth increase during the pulse and fell at the end of the negative region. Different rates of CH4 conversion were calculated from the DLC deposition rate. These were explained in terms of the specific activation energy Ea and the conversion factor xdep associated with the plasma processes. The work deepens our understanding of the advantages of using pulsed power supplies for the PECVD of hard metallic and protective coatings for industrial applications (optics

  20. Homogeneity of metal matrix composites deposited by plasma transferred arc welding

    NASA Astrophysics Data System (ADS)

    Wolfe, Tonya Brett Bunton

    Tungsten carbide-based metal matrix composite coatings are deposited by PTAW (Plasma Transferred Arc Welding) on production critical components in oil sands mining. Homogeneous distribution of the reinforcement particles is desirable for optimal wear resistance in order to reduce unplanned maintenance shutdowns. The homogeneity of the coating can be improved by controlling the heat transfer, solidification rate of the process and the volume fraction of carbide. The degree of settling of the particles in the deposit was quantified using image analysis. The volume fraction of carbide was the most significant factor in obtaining a homogeneous coating. Lowering the current made a modest improvement in homogeneity. Changes made in other operational parameters did not effect significant changes in homogeneity. Infrared thermography was used to measure the temperature of the surface of the deposit during the welding process. The emissivity of the materials was required to acquire true temperature readings. The emissivity of the deposit was measured using laser reflectometry and was found to decrease from 0.8 to 0.2 as the temperature increased from 900°C to 1200°C. A correction algorithm was applied to calculate the actual temperature of the surface of the deposit. The corrected temperature did increase as the heat input of the weld increased. A one dimensional mathematical model of the settling profile and solidification of the coatings was developed. The model considers convective and radiative heat input from the plasma, the build-up of the deposit, solidification of the deposit and the settling of the WC particles within the deposit. The model had very good agreement with the experimental results of the homogeneity of the carbide as a function of depth. This fundamental model was able to accurately predict the particle homogeneity of an MMC deposited by an extremely complicated process. It was shown that the most important variable leading to a homogeneous coating

  1. Low-Temperature Plasma-Assisted Atomic Layer Deposition of Silicon Nitride Moisture Permeation Barrier Layers.

    PubMed

    Andringa, Anne-Marije; Perrotta, Alberto; de Peuter, Koen; Knoops, Harm C M; Kessels, Wilhelmus M M; Creatore, Mariadriana

    2015-10-14

    Encapsulation of organic (opto-)electronic devices, such as organic light-emitting diodes (OLEDs), photovoltaic cells, and field-effect transistors, is required to minimize device degradation induced by moisture and oxygen ingress. SiNx moisture permeation barriers have been fabricated using a very recently developed low-temperature plasma-assisted atomic layer deposition (ALD) approach, consisting of half-reactions of the substrate with the precursor SiH2(NH(t)Bu)2 and with N2-fed plasma. The deposited films have been characterized in terms of their refractive index and chemical composition by spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). The SiNx thin-film refractive index ranges from 1.80 to 1.90 for films deposited at 80 °C up to 200 °C, respectively, and the C, O, and H impurity levels decrease when the deposition temperature increases. The relative open porosity content of the layers has been studied by means of multisolvent ellipsometric porosimetry (EP), adopting three solvents with different kinetic diameters: water (∼0.3 nm), ethanol (∼0.4 nm), and toluene (∼0.6 nm). Irrespective of the deposition temperature, and hence the impurity content in the SiNx films, no uptake of any adsorptive has been observed, pointing to the absence of open pores larger than 0.3 nm in diameter. Instead, multilayer development has been observed, leading to type II isotherms that, according to the IUPAC classification, are characteristic of nonporous layers. The calcium test has been performed in a climate chamber at 20 °C and 50% relative humidity to determine the intrinsic water vapor transmission rate (WVTR) of SiNx barriers deposited at 120 °C. Intrinsic WVTR values in the range of 10(-6) g/m2/day indicate excellent barrier properties for ALD SiNx layers as thin as 10 nm, competing with that of state-of-the-art plasma-enhanced chemical vapor-deposited SiNx layers of a few hundred

  2. Deposition of Functional Coatings Based on Intermetallic Systems TiAl on the Steel Surface by Vacuum Arc Plasma

    NASA Astrophysics Data System (ADS)

    Budilov, V.; Vardanyan, E.; Ramazanov, K.

    2015-11-01

    Laws governing the formation of intermetallic phase by sequential deposition of nano-sized layers coatings from vacuum arc plasma were studied. Mathematical modeling process of deposition by vacuum arc plasma was performed. In order to identify the structural and phase composition of coatings and to explain their physical and chemical behaviour XRD studies were carried out. Production tests of the hardened punching tools were performed.

  3. Increased Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

    DOEpatents

    Li, Yaun-Min; Bennett, Murray S.; Yang, Liyou

    1997-07-08

    High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

  4. Increasing Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

    DOEpatents

    Li, Yaun-Min; Bennett, Murray S.; Yang, Liyou

    1999-08-24

    High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

  5. Model of a two-stage rf plasma reactor for SiC deposition

    NASA Astrophysics Data System (ADS)

    Petrov, G. M.; Giuliani, J. L.

    2001-07-01

    A reactor is proposed for plasma-enhanced chemical-vapor deposition of silicon carbide (SiC) at low pressure (˜few Torr). The inductively coupled plasma lies upstream of the growth substrate and serves to dissociate the precursor silane/propane/hydrogen inlet gas. Unlike existing reactors, the design offers the potential for separate control of the temperature in the dissociation region and at the growth substrate. The geometrical parameters and flow conditions appropriate for SiC growth are analyzed with a one-dimensional flow simulation model which includes approximations for lateral diffusive losses to cold walls as well as deposition to the substrate. Twenty-one neutral species and 24 ions are followed with 179 reactions. At 3 Torr, 10 W/cm3, and 300 cm/s inlet flow velocity, the model predicts a growth rate of ˜3 μm/h downstream from the plasma. Negligible ion density exists over the substrate as long as the silane density is sufficiently large due to a feedback process between Si+ and SiH4. Besides heating the gas, the plasma is an efficient source of radical H atoms, which in turn control the abundance of some hydrocarbon species over the substrate. C2H2 is the dominant contributor to the C-bearing flux onto the substrate and the Si atom, which forms by electron reactions, is the most important Si-bearing species. Finally, a sensitive transition in deposition rate is found for the C-bearing species as the power increases from 5 to 10 W/cm3.

  6. View factor modeling of sputter-deposition on micron-scale-architectured surfaces exposed to plasma

    NASA Astrophysics Data System (ADS)

    Huerta, C. E.; Matlock, T. S.; Wirz, R. E.

    2016-03-01

    The sputter-deposition on surfaces exposed to plasma plays an important role in the erosion behavior and overall performance of a wide range of plasma devices. Plasma models in the low density, low energy plasma regime typically neglect micron-scale surface feature effects on the net sputter yield and erosion rate. The model discussed in this paper captures such surface architecture effects via a computationally efficient view factor model. The model compares well with experimental measurements of argon ion sputter yield from a nickel surface with a triangle wave geometry with peak heights in the hundreds of microns range. Further analysis with the model shows that increasing the surface pitch angle beyond about 45° can lead to significant decreases in the normalized net sputter yield for all simulated ion incident energies (i.e., 75, 100, 200, and 400 eV) for both smooth and roughened surfaces. At higher incident energies, smooth triangular surfaces exhibit a nonmonotonic trend in the normalized net sputter yield with surface pitch angle with a maximum yield above unity over a range of intermediate angles. The resulting increased erosion rate occurs because increased sputter yield due to the local ion incidence angle outweighs increased deposition due to the sputterant angular distribution. The model also compares well with experimentally observed radial expansion of protuberances (measuring tens of microns) in a nano-rod field exposed to an argon beam. The model captures the coalescence of sputterants at the protuberance sites and accurately illustrates the structure's expansion due to deposition from surrounding sputtering surfaces; these capabilities will be used for future studies into more complex surface architectures.

  7. [Optical Spectroscopy for High-Pressure Microwave Plasma Chemical Vapor Deposition of Diamond Films].

    PubMed

    Cao, Wei; Ma, Zhi-bin

    2015-11-01

    Polycrystalline diamond growth by microwave plasma chemical vapor deposition (MPCVD) at high-pressure (34.5 kPa) was investigated. The CH₄/H₂/O₂plasma was detected online by optical emission spectroscopy (OES), and the spatial distribution of radicals in the CH₄/H₂/O₂plasma was studied. Raman spectroscopy was employed to analyze the properties of the diamond films deposited in different oxygen volume fraction. The uniformity of diamond films quality was researched. The results indicate that the spectrum intensities of C₂, CH and Hα decrease with the oxygen volume fraction increasing. While the intensity ratios of C₂, CH to Hα also reduced as a function of increasing oxygen volume fraction. It is shown that the decrease of the absolute concentration of carbon radicals is attributed to the rise volume fraction of oxygen, while the relative concentration of carbon radicals to hydrogen atom is also reducing, which depressing the growth rate but improving the quality of diamond film. Furthermore, the OH radicals, role of etching, its intensities increase with the increase of oxygen volume fraction. Indicated that the improvement of OH concentration is also beneficial to reduce the content of amorphous carbon in diamond films. The spectrum space diagnosis results show that under high deposition pressure the distribution of the radicals in the CH₄/H₂/O₂plasma is inhomogeneous, especially, that of radical C₂ gathered in the central region. And causing a rapid increase of non-diamond components in the central area, eventually enable the uneven distribution of diamond films quality. PMID:26978897

  8. Control of carbon content in amorphous GeTe films deposited by plasma enhanced chemical vapor deposition (PE-MOCVD) for phase-change random access memory applications

    NASA Astrophysics Data System (ADS)

    Aoukar, M.; Szkutnik, P. D.; Jourde, D.; Pelissier, B.; Michallon, P.; Noé, P.; Vallée, C.

    2015-07-01

    Amorphous and smooth GeTe thin films are deposited on 200 mm silicon substrates by plasma enhanced—metal organic chemical vapor deposition (PE-MOCVD) using the commercial organometallic precursors TDMAGe and DIPTe as Ge and Te precursors, respectively. X-ray photoelectron spectroscopy (XPS) measurements show a stoichiometric composition of the deposited GeTe films but with high carbon contamination. Using information collected by Optical Emission Spectroscopy (OES) and XPS, the origin of carbon contamination is determined and the dissociation mechanisms of Ge and Te precursors in H2 + Ar plasma are proposed. As a result, carbon level is properly controlled by varying operating parameters such as plasma radio frequency power, pressure and H2 rate. Finally, GeTe films with carbon level as low as 5 at. % are obtained.

  9. Chain Assemblies from Nanoparticles Synthesized by Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition: The Computational View.

    PubMed

    Mishin, Maxim V; Zamotin, Kirill Y; Protopopova, Vera S; Alexandrov, Sergey E

    2015-12-01

    This article refers to the computational study of nanoparticle self-organization on the solid-state substrate surface with consideration of the experimental results, when nanoparticles were synthesised during atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD). The experimental study of silicon dioxide nanoparticle synthesis by AP-PECVD demonstrated that all deposit volume consists of tangled chains of nanoparticles. In certain cases, micron-sized fractals are formed from tangled chains due to deposit rearrangement. This work is focused on the study of tangled chain formation only. In order to reveal their formation mechanism, a physico-mathematical model was developed. The suggested model was based on the motion equation solution for charged and neutral nanoparticles in the potential fields with the use of the empirical interaction potentials. In addition, the computational simulation was carried out based on the suggested model. As a result, the influence of such experimental parameters as deposition duration, particle charge, gas flow velocity, and angle of gas flow was found. It was demonstrated that electrical charges carried by nanoparticles from the discharge area are not responsible for the formation of tangled chains from nanoparticles, whereas nanoparticle kinetic energy plays a crucial role in deposit morphology and density. The computational results were consistent with experimental results. PMID:26682441

  10. Low temperature, fast deposition of metallic titanium nitride films using plasma activated reactive evaporation

    SciTech Connect

    Montes de Oca Valero, J.A.; Le Petitcorps, Y.; Manaud, J.P.; Chollon, G.; Carrillo Romo, F.J.; Lopez M, A.

    2005-05-01

    Titanium and titanium nitride thin films were deposited on silica glass and W substrates at a high coating growth rate by plasma-activated reactive evaporation (ARE). The crystal structure, preferred orientation and grain size of the coatings were determined by x-ray diffraction (XRD) technique using Cu-K{alpha} x rays. The analysis of the coating morphology was performed by field-emission scanning electron microscopy (FE-SEM). The composition of the films was analyzed by Auger electron spectroscopy (AES) and electron-probe microanalysis (EPMA). The titanium and titanium nitride condensates were collected on a carbon-coated collodion film then characterized by transmission electron microscopy (TEM) in order to study the structures of the deposits at very short deposition times. The resistivity of the films was measured by using the four-point-probe method. The titanium coatings were found to consist of very fine particles (40 nm in grain size) and to exhibit a strong (002) texture. The titanium nitride coatings were substoichiometric (TiN{sub x},x<1), with an oxygen content ranging from 7 to 15 at. % depending on the deposition conditions. The deposits were found to exhibit a (111) preferred orientation. This behavior became stronger with coating thickness. In spite of the presence of oxygen, all the TiN{sub x} coatings obtained at low temperature and a high growth rate in this work exhibited a rather high electrical conductivity.

  11. Differing morphologies of textured diamond films with electrical properties made with microwave plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Lai, Wen Chi; Wu, Yu-Shiang; Chang, Hou-Cheng; Lee, Yuan-Haun

    2010-12-01

    This study investigates the orientation of textured diamond films produced through microwave plasma chemical vapor deposition (MPCVD) at 1200 W, 110 Torr, CH 4/H 2 = 1/20, with depositions times of 0.5-4.0 h. After a growth period of 2.0-4.0 h, this particular morphology revealed a rectangular structure stacked regularly on the diamond film. The orientation on {1 1 1}-textured diamond films grew a preferred orientation of {1 1 0} on the surface, as measured by XRD. The formation of the diamond epitaxial film formed textured octahedrons in ball shaped (or cauliflower-like) diamonds in the early stages (0.5 h), and the surface of the diamond film extended to pile the rectangular structure at 4.0 h. The width of the tier was approximately 200 nm at the 3.0 h point of deposition, according to TEM images. The results revealed that the textured diamond films showed two different morphological structures (typical ball shaped and rectangular diamonds), at different stages of the deposition period. The I- V characteristics of the oriented diamond films after 4.0 h of deposition time showed good conformity with the ohmic contact.

  12. Plasma deposited composite coatings to control biological response of osteoblast-like MG-63 cells

    NASA Astrophysics Data System (ADS)

    Keremidarska, M.; Radeva, E.; Eleršič, K.; Iglič, A.; Pramatarova, L.; Krasteva, N.

    2014-12-01

    The successful osseointegration of a bone implant is greatly dependent on its ability to support cellular adhesion and functions. Deposition of thin composite coatings onto the implant surface is a promising approach to improve interactions with cells without compromising implant bulk properties. In this work, we have developed composite coatings, based on hexamethyldisiloxane (HMDS) and detonation nanodiamond (DND) particles and have studied adhesion, growth and function of osteoblast-like MG-63 cells. PPHMDS/DND composites are of interest for orthopedics because they combine superior mechanical properties and good biocompatibility of DND with high adherence of HMDS to different substrata including glass, metals and plastics. We have used two approaches of the implementation of DND particles into a polymer matrix: pre-mixture of both components followed by plasma polymerization and layer-by-layer deposition of HMDS and DND particles and found that the deposition approach affects significantly the surface properties of the resulting layers and cell behaviour. The composite, prepared by subsequent deposition of monomer and DND particles was hydrophilic, with a rougher surface and MG-63 cells demonstrated better spreading, growth and function compared to the other composite which was hydrophobic with a smooth surface similarly to unmodified polymer. Thus, by varying the deposition approach, different PPHMDS/DND composite coatings, enhancing or inhibiting osteoblast adhesion and functions, can be obtained. In addition, the effect of fibronectin pre-adsorption was studied and was found to increase greatly MG-63 cell spreading.

  13. Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Gates, S. M.; Neumayer, D. A.; Sherwood, M. H.; Grill, A.; Wang, X.; Sankarapandian, M.

    2007-05-01

    The preparation of ultralow dielectric constant porous silicon, carbon, oxygen, hydrogen alloy dielectrics, called "pSiCOH," using a production 200mm plasma enhanced chemical vapor deposition tool and a thermal treatment is reported here. The effect of deposition temperature on the pSiCOH film is examined using Fourier transform infrared (FTIR) spectroscopy, dielectric constant (k), and film shrinkage measurements. For all deposition temperatures, carbon in the final porous film is shown to be predominantly Si -CH3 species, and lower k is shown to correlate with increased concentration of Si -CH3. NMR and FTIR spectroscopies clearly detect the loss of a removable, unstable, hydrocarbon (CHx) phase during the thermal treatment. Also detected are increased cross-linking of the Si-O skeleton, and concentration changes for three distinct structures of carbon. In the as deposited films, deposition temperature also affects the hydrocarbon (CHx) content and the presence of C O and C C functional groups.

  14. PREFACE: VI Scientific Technical Conference on "Low-temperature plasma during the deposition of functional coatings"

    NASA Astrophysics Data System (ADS)

    2014-11-01

    The VI Republican Scientific Technical Conference "Low-temperature plasma during the deposition of functional coatings" took place from 4 to 7 November 2014 at the Academy of Sciences of the Republic of Tatarstan and the Kazan Federal University. The conference was chaired by a Member of the Academy of Sciences of the Republic of Tatarstan Nail Kashapov -Professor, Doctor of Technical Sciences- a member of the Scientific and Technical Council of the Ministry of Economy of the Republic of Tatarstan. At the conference, the participants discussed a wide range of issues affecting the theoretical and computational aspects of research problems in the physics and technology of low-temperature plasma. A series of works were devoted to the study of thin films obtained by low-temperature plasma. This year work dedicated to the related field of heat mass transfer in multiphase media and low-temperature plasma was also presented. Of special interest were reports on the exploration of gas discharges with liquid electrolytic electrotrodes and the study of dusty plasmas. Kashapov Nail, D.Sc., Professor (Kazan Federal University)

  15. Preparation and characterization of ZnO-deposited DBD plasma-treated PP packaging film with antibacterial activities

    NASA Astrophysics Data System (ADS)

    Paisoonsin, Sutida; Pornsunthorntawee, Orathai; Rujiravanit, Ratana

    2013-05-01

    Zinc oxide (ZnO)-deposited polypropylene (PP) packaging film was prepared with the aid of dielectric barrier discharge (DBD) plasma treatment. The surface hydrophilicity of PP film was found to increase after the DBD plasma treatment due to the presence of oxygen-containing functional groups on the DBD plasma-treated PP surface. Although the surface roughness of the DBD plasma-treated PP film gradually increased with increasing plasma treatment time, the DBD plasma treatment insignificantly affected the mechanical properties of the PP film. The DBD plasma treatment time was found to be optimized at 10 s. The DBD plasma-treated PP film was further immersed in an aqueous zinc nitrate (Zn(NO3)2) solution at different concentrations before being converted to ZnO particles with the use of a 2.5 M sodium hydroxide (NaOH) solution, followed by sonication. The highest amount of ZnO deposited on the DBD plasma-treated PP surface was about 0.26 wt.% at the optimum Zn(NO3)2 concentration of 0.5 M. The ZnO-deposited DBD plasma-treated PP film showed good antibacterial activities against gram-positive Staphylococcus auerus and gram-negative Escherichia coli.

  16. Long period gratings coated with hafnium oxide by plasma-enhanced atomic layer deposition for refractive index measurements.

    PubMed

    Melo, Luis; Burton, Geoff; Kubik, Philip; Wild, Peter

    2016-04-01

    Long period gratings (LPGs) are coated with hafnium oxide using plasma-enhanced atomic layer deposition (PEALD) to increase the sensitivity of these devices to the refractive index of the surrounding medium. PEALD allows deposition at low temperatures which reduces thermal degradation of UV-written LPGs. Depositions targeting three different coating thicknesses are investigated: 30 nm, 50 nm and 70 nm. Coating thickness measurements taken by scanning electron microscopy of the optical fibers confirm deposition of uniform coatings. The performance of the coated LPGs shows that deposition of hafnium oxide on LPGs induces two-step transition behavior of the cladding modes. PMID:27137052

  17. Correlation between optical characterization of the plasma in reactive magnetron sputtering deposition of Zr N on SS 316L and surface and mechanical properties of the deposited films

    NASA Astrophysics Data System (ADS)

    Fragiel, A.; Machorro, R.; Muñoz-Saldaña, J.; Salinas, J.; Cota, L.

    2008-05-01

    Optical and surface spectroscopies as well as nanoindentation techniques have been used to study ZrN coatings on 316L stainless steel obtained by DC-reactive magnetron sputtering. The deposit process was carried out using initial and working pressures of 10 -6 Torr and 10 -3 Torr, respectively. The experimental set-up for optical spectra acquisition was designed for the study in situ of the plasma in the deposition chamber. Auger spectroscopy, SEM and X-ray diffraction were used to characterize the coatings. Nanoindentation tests were carried out to measure the mechanical properties of the coating. Plasma characterization revealed the presence of CN molecules and Cr ions in the plasma. Surface spectroscopy results showed that ZrN, Zr 3N 4 and ZrC coexist in the coating. These results allowed the understanding of the mechanical behavior of the coatings, demonstrating the importance of the plasma characterization as a tool for tailoring the properties of hard coatings.

  18. Erosion and re-deposition of lithium and boron coatings under high-flux plasma bombardment

    NASA Astrophysics Data System (ADS)

    Abrams, Tyler Wayne

    Lithium and boron coatings are applied to the walls of many tokamaks to enhance performance and protect the underlying substrates. Li and B-coated high-Z substrates are planned for use in NSTX-U and are a candidate plasma-facing component (PFC) for DEMO. However, previous measurements of Li evaporation and thermal sputtering on low-flux devices indicate that the Li temperature permitted on such devices may be unacceptably low. Thus it is crucial to characterize gross and net Li erosion rates under high-flux plasma bombardment. Additionally, no quantitative measurements have been performed of the erosion rate of a boron-coated PFC during plasma bombardment. A realistic model for the compositional evolution of a Li layer under D bombardment was developed that incorporates adsorption, implantation, and diffusion. A model was developed for temperature-dependent mixed-material Li-D erosion that includes evaporation, physical sputtering, chemical sputtering, preferential sputtering, and thermal sputtering. The re-deposition fraction of a Li coating intersecting a linear plasma column was predicted using atomic physics information and by solving the Li continuity equation. These models were tested in the Magnum-PSI linear plasma device at ion fluxes of 1023-1024 m-2 s-1 and Li surface temperatures less than 800 degrees C. Li erosion was measured during bombardment with a neon plasma that will not chemically react with Li and the results agreed well with the erosion model. Next the ratio of the total D fluence to the areal density of the Li coating was varied to quantify differences in Li erosion under D plasma bombardment as a function of the D concentration. The ratio of D/Li atoms was calculated using the results of MD simulations and good agreement is observed between measurements and the predictions of the mixed-material erosion model. Li coatings are observed to disappear from graphite much faster than from TZM Mo, indicating that fast Li diffusion into the bulk

  19. Adhesion, friction, and wear of plasma-deposited thin silicon nitride films at temperatures to 700 C

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Pouch, J. J.; Alterovitz, S. A.; Pantic, D. M.; Johnson, G. A.

    1988-01-01

    The adhesion, friction, and wear behavior of silicon nitride films deposited by low- and high-frequency plasmas (30 kHz and 13.56 MHz) at various temperatures to 700 C in vacuum were examined. The results of the investigation indicated that the Si/N ratios were much greater for the films deposited at 13.56 MHz than for those deposited at 30 kHz. Amorphous silicon was present in both low- and high-frequency plasma-deposited silicon nitride films. However, more amorphous silicon occurred in the films deposited at 13.56 MHz than in those deposited at 30 kHz. Temperature significantly influenced adhesion, friction, and wear of the silicon nitride films. Wear occurred in the contact area at high temperature. The wear correlated with the increase in adhesion and friction for the low- and high-frequency plasma-deposited films above 600 and 500 C, respectively. The low- and high-frequency plasma-deposited thin silicon nitride films exhibited a capability for lubrication (low adhesion and friction) in vacuum at temperatures to 500 and 400 C, respectively.

  20. Adhesion, friction, and wear of plasma-deposited thin silicon nitride films at temperatures to 700 C

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Pouch, J. J.; Alterovitz, S. A.; Pantic, D. M.; Johnson, G. A.

    1989-01-01

    The adhesion, friction, and wear behavior of silicon nitride films deposited by low- and high-frequency plasmas (30 kHz and 13.56 MHz) at various temperatures to 700 C in vacuum were examined. The results of the investigation indicated that the Si/N ratios were much greater for the films deposited at 13.56 MHz than for those deposited at 30 kHz. Amorphous silicon was present in both low- and high-frequency plasma-deposited silicon nitride films. However, more amorphous silicon occurred in the films deposited at 13.56 MHz than in those deposited at 30 kHz. Temperature significantly influenced adhesion, friction, and wear of the silicon nitride films. Wear occurred in the contact area at high temperature. The wear correlated with the increase in adhesion and friction for the low- and high-frequency plasma-deposited films above 600 and 500 C, respectively. The low- and high-frequency plasma-deposited thin silicon nitride films exhibited a capability for lubrication (low adhesion and friction) in vacuum at temperatures to 500 and 400 C, respectively.

  1. High Anatase Rate Titanium Dioxide Coating Deposition by Low Power Microwave Plasma Spray

    NASA Astrophysics Data System (ADS)

    Redza, Ahmad; Kondo, Toshiki; Yasui, Toshiaki; Fukumoto, Masahiro

    2016-02-01

    Titanium dioxide is a promising photocatalyst material because of the magnificent properties of this material where it is able to remove the air pollution substance and the deodorizing function. Generally, the deposition method of a titanium dioxide coating is carried out by an organic system binder but the powerful photocatalytic reaction will degrades the binder. Therefore, thermal spray is considered to be the alternative method but this method will induce crystallization transformation of titanium dioxide from anatase phase with high photocatalytic activity to rutile phase with low photocatalyst which caused by high heat input. Since our microwave plasma spraying device is operable at low power comparing with conventional high power plasma spray, the reduce effect of the heat input onto the particles at the time of spraying can be achieved and coating deposition with high rate of anatase phase is expected. Therefore, in this research, the coating deposition by controlling the heat input into the spray particle which can be resulted in high rate of anatase phase with high photocatalytic activity was conducted. By controlled condition, coating with optimum anatase rate of 83% is able to be fabricated by this method.

  2. Low-energy deposition of high-strength Al(0) alloys from an ECR plasma

    SciTech Connect

    Barbour, J.C.; Follstaedt, D.M.; Knapp, J.A.; Myers, S.M.; Marshall, D.A.; Lad, R.J.

    1995-12-31

    Low-energy deposition of Al(O) alloys from an electron cyclotron resonance (ECR) plasma offers a scaleable method for the synthesis of thick, high-strength Al layers. This work compares alloy layers formed by an ECR-0{sub 2} plasma in conjunction with Al evaporation to 0-implanted Al (ion energies 25-200 keV); and it examines the effects of volume fraction of A1{sub 2}0{sub 3} phase and deposition temperature on the yield stress of the material. TEM showed the Al(O) alloys contain a dense dispersion of small {gamma}-Al{sub 2}0{sub 3} precipitates ({approximately}l nm) in a fine-grain (10-100 nm) fcc Al matrix when deposited at a temperature of {approximately}100C, similar to the microstructure for gigapascal-strength 0-implanted Al. Nanoindentation gave hardnesses for ECR films from 1.1 to 3.2 GPa, and finite-element modeling gave yield stresses up to 1.3 {plus_minus} 0.2 GPa with an elastic modulus of 66 GPa {plus_minus} 6 GPa (similar to pure bulk Al). The yield stress of a polycrystalline pure Al layer was only 0.19 {plus_minus} 0.02 GPa, which was increased to 0.87 {plus_minus} 0.15 GPa by implantation with 5 at. % 0.

  3. Controlled surface diffusion in plasma-enhanced chemical vapor deposition of GaN nanowires.

    PubMed

    Hou, Wen Chi; Hong, Franklin Chau-Nan

    2009-02-01

    This study investigates the growth of GaN nanowires by controlling the surface diffusion of Ga species on sapphire in a plasma-enhanced chemical vapor deposition (CVD) system. Under nitrogen-rich growth conditions, Ga has a tendency to adsorb on the substrate surface diffusing to nanowires to contribute to their growth. The significance of surface diffusion on the growth of nanowires is dependent on the environment of the nanowire on the substrate surface as well as the gas phase species and compositions. Under nitrogen-rich growth conditions, the growth rate is strongly dependent on the surface diffusion of gallium, but the addition of 5% hydrogen in nitrogen plasma instantly diminishes the surface diffusion effect. Gallium desorbs easily from the surface by reaction with hydrogen. On the other hand, under gallium-rich growth conditions, nanowire growth is shown to be dominated by the gas phase deposition, with negligible contribution from surface diffusion. This is the first study reporting the inhibition of surface diffusion effects by hydrogen addition, which can be useful in tailoring the growth and characteristics of nanowires. Without any evidence of direct deposition on the nanowire surface, gallium and nitrogen are shown to dissolve into the catalyst for growing the nanowires at 900 degrees C. PMID:19417353

  4. Friction and wear of plasma-deposited amorphous hydrogenated films on silicon nitride

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1991-01-01

    An investigation was conducted to examine the friction and wear behavior of amorphous hydrogenated carbon (a-C:H) films in sliding contact with silicon nitride pins in both dry nitrogen and humid air environments. Amorphous hydrogenated carbon films approximately 0.06 micron thick were deposited on silicon nitride flat substrates by using the 30 kHz ac glow discharge of a planar plasma reactor. The results indicate that an increase in plasma deposition power gives an increase in film density and hardness. The high-density a-C:H films deposited behaved tribologically much like bulk diamond. In the dry nitrogen environment, a tribochemical reaction produced a substance, probably a hydrocarbon-rich layer, that decreased the coefficient of friction. In the humid air environment, tribochemical interactions drastically reduced the wear life of a-C:H films and water vapor greatly increased the friction. Even in humid air, effective lubrication is possible with vacuum-annealed a-C:H films. The vacuum-annealed high-density a-C:H film formed an outermost superficial graphitic layer, which behaved like graphite, on the bulk a-C:H film. Like graphite, the annealed a-C:H film with the superficial graphitic layer showed low friction when adsorbed water vapor was present.

  5. Characterisation of nano-crystalline titanium dioxide films grown by atmospheric pressure plasma electrolytic deposition

    NASA Astrophysics Data System (ADS)

    Paulmier, Thierry; Bell, John M.; Fredericks, Peter M.

    2006-01-01

    A new atmospheric pressure plasma electrolytic process has been developed for the deposition of TiO II crystalline thin films on metal substrate. Contrary to the other deposition techniques, the process occurs in a liquid precursor, composed of titanium tetraisopropoxide and absolute ethanol. A plasma discharge is created and confined around the cathode in a superheated vapour sheath surrounded by the liquid phase, inducing the production of a thin TiO II coating at the surface of the cathode. Because of the flexibility of the operating parameters, this technology allows the rapid deposition of thin films with a wide range of structural and physical properties. This process enables therefore the production of nanocrystalline titania films with adjustable morphology and structure (anatase, rutile) by adjusting the operating voltage, current intensity, the treatment time and calcination temperature. The analysis of the structure and composition of these TiO II coatings have been carried out by Scanning Electron Microscopy, Transmission Electron Microscopy, Raman spectroscopy, X-ray Photoelectron Spectroscopy and X-Ray Diffraction. A thorough study has been performed to understand the influence of the operating parameters on the properties and structure of the coatings.

  6. Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

    SciTech Connect

    Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J.

    2015-11-02

    Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH{sub 4}/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H{sub 2} into the deposition gas chemistry. Electronically excited species of CN, C{sub 2}, Ar, N{sub 2}, CH, H{sub β}, and H{sub α} were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T{sub 2g} phonon at 1333 cm{sup −1} peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.

  7. Development of an electrospray approach to deposit complex molecules on plasma modified surfaces

    NASA Astrophysics Data System (ADS)

    Kitching, K. J.; Lee, H.-N.; Elam, W. T.; Johnston, E. E.; MacGregor, H.; Miller, R. J.; Turecek, F.; Ratner, B. D.

    2003-11-01

    Two established techniques have been coupled to allow surfaces to be precision engineered. Electrospray ionization to bring large, complex, intact molecular ions into the gas phase has been interfaced with a radio frequency (rf) plasma reactor to treat surfaces making them receptive to the deposition of active biomolecules. The new instrument has been designed and used successfully to deposit a number of high molecular weight molecules including the polysaccharide, sodium hyaluronan (HA), that has an important role in a number of physiological functions. Substrate material is treated using a rf glow discharge plasma chamber, to clean and activate the surface in a controlled manner, then exposed to a beam of multiply charged ions in the gas phase that have been generated using electrospray techniques. The ions are deposited gently onto the substrate and become covalently bound. The molecular integrity and stability of HA surfaces prepared in this way was established using x-ray photoelectron spectroscopy, changes in the observed contact angle, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, and a biological assay-platelet adhesion to the surface.

  8. Formation of microchannels from low-temperature plasma-deposited silicon oxynitride

    DOEpatents

    Matzke, Carolyn M.; Ashby, Carol I. H.; Bridges, Monica M.; Manginell, Ronald P.

    2000-01-01

    A process for forming one or more fluid microchannels on a substrate is disclosed that is compatible with the formation of integrated circuitry on the substrate. The microchannels can be formed below an upper surface of the substrate, above the upper surface, or both. The microchannels are formed by depositing a covering layer of silicon oxynitride over a mold formed of a sacrificial material such as photoresist which can later be removed. The silicon oxynitride is deposited at a low temperature (.ltoreq.100.degree. C.) and preferably near room temperature using a high-density plasma (e.g. an electron-cyclotron resonance plasma or an inductively-coupled plasma). In some embodiments of the present invention, the microchannels can be completely lined with silicon oxynitride to present a uniform material composition to a fluid therein. The present invention has applications for forming microchannels for use in chromatography and electrophoresis. Additionally, the microchannels can be used for electrokinetic pumping, or for localized or global substrate cooling.

  9. Time-resolved diagnostics of excimer laser-generated ablation plasmas used for pulsed laser deposition

    SciTech Connect

    Geohegan, D.B.

    1994-09-01

    Characteristics of laser plasmas used for pulsed laser deposition (PLD) of thin films are examined with four in situ diagnostic techniques: Optical emission spectroscopy, optical absorption spectroscopy, ion probe studies, and gated ICCD (intensified charge-coupled-device array) fast photography. These four techniques are complementary and permit simultaneous views of the transport of ions, excited states, ground state neutrals and ions, and hot particulates following KrF laser ablation of YBCO, BN, graphite and Si in vacuum and background gases. The implementation and advantages of the four techniques are first described in order to introduce the key features of laser plasmas for pulsed laser deposition. Aspects of the interaction of the ablation plume with background gases (i.e., thermalization, attenuation, shock formation) and the collision of the plasma plume with the substrate heater are then summarized. The techniques of fast ICCD photography and gated photon counting are then applied to investigate the temperature, velocity, and spatial distribution of hot particles generated during KrF ablation of YBCO, BN, Si and graphite. Finally, key features of fast imaging of the laser ablation of graphite into high pressure rare gases are presented in order to elucidate internal reflected shocks within the plume, redeposition of material on a surface, and formation of hot nanoparticles within the plume.

  10. The augmented saddle field discharge characteristics and its applications for plasma enhanced chemical vapour deposition

    SciTech Connect

    Wong, Johnson; Yeghikyan, Davit; Kherani, Nazir P.

    2013-04-07

    A high ion flux parallel electrode plasma is proposed and studied in its DC configuration. By cascading a diode source region which supplies electrons and a saddle field region where these seed electrons are energized and amplified, the energy of ion bombardment on the substrate can be decoupled from the plasma density. The sufficiently large density of electrons and holes in the vicinity of the substrate raises the possibility to perform plasma enhanced chemical vapour deposition on insulating materials, at low sheath voltages (around 40 V in the configuration studied), at low temperatures in which the surface mobility of film growth species may be provided by the bombardment of moderate energy ions. As a benchmarking exercise, experiments are carried out on silane discharge characteristics and deposition of hydrogenated amorphous silicon (a-Si:H) on both silicon wafer and glass. The films grown at low anode voltages have excellent microstructures with predominantly monohydride bonds, sharp band tails, but relatively high integrated defect density in the mid 10{sup 16}/cm{sup 3} range for the particular substrate temperature of 180 Degree-Sign C, indicating that further optimizations are necessary if the electrode configuration is to be used to create a-Si:H devices.

  11. Effect of buoyancy on power deposition in microwave cavity hydrogen plasma source

    NASA Astrophysics Data System (ADS)

    Prasanna, S.; Rond, C.; Michau, A.; Hassouni, K.; Gicquel, A.

    2016-08-01

    A self-consistent model describing the coupling of resonant microwave radiation and plasma has been constructed. This model improves upon the models developed by Hassouni et al and Hagelaar et al, in 1999 and 2004, respectively with inclusion of hydrodynamic effects. The model has been used to study the effect of buoyancy on power deposition in microwave assisted hydrogen plasmas at different operating pressures over the range 25–300 mbar and power over the range 400 and 4000 W. Three cases viz. normal reactor (g  =  ‑9.81 m s‑2, negative buoyancy), pure diffusion (g  =  0 m s‑2) and the inverted case (g  =  9.81 m s‑2, positive buoyancy) were considered. Buoyancy effects in the cavity become important at high power / pressure operating conditions. The formation of a secondary plasma zone is strongly increased in the presence of negative buoyancy, while positive buoyancy and diffusion cases are more stable. Also the density of atomic hydrogen close to the substrate is larger with a wider radial spread for the positive buoyancy case over normal operating conditions which augurs well for achieving good deposition of diamond.

  12. Spatially resolved spectroscopy of an impulse plasma for thin film deposition

    NASA Astrophysics Data System (ADS)

    Kułakowska-Pawlak, Barbara

    2009-08-01

    Radially resolved emission measurements have been employed for a better understanding of plasma generated in a pulsed coaxial accelerator operating in a mixture of propane and butane under conditions which enable diamond-like layer deposition. The measurements were taken at two positions along the axis of symmetry of the discharge. Assuming the Boltzmann and Saha equilibrium, the emission from the plasma has been quantified. Abel-transformed radial profiles of the spectral lines of C I, C II and C III have been used to study radial changes in the concentration of excited neutral, singly and doubly ionized carbon, in the excitation temperature, in the ionization temperature and in the electron number density. Values of excitation and ionization temperatures and their radial profiles for a given axial position did not differ significantly. On the axis of symmetry of the discharge, the excitation temperature of C II and the electron density were found to reach values of about 29 000 K and 5 × 1017 cm-3, respectively. In addition, the relative densities of the C, C+ and C2+ species were evaluated, and hence the spatial inhomogeneous plasma structure with respect to the distribution of neutral and ionized fractions of carbon has been revealed and discussed in terms of deposition conditions.

  13. Fluoropolymer Films Deposited by RF Plasma Sputtering of Polytetrafluoroethylene Using Inert Gases

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Wydeven, Theodore; Kliss, Mark (Technical Monitor)

    1998-01-01

    The FT-IR (Fourier Transform Infrared), UV (Ultraviolet) and XPS (X Ray Photoelectron Spectroscopy) spectra of fluoropolymer films (SPTFE) deposited by rf (radio frequency) plasma sputtering of polytetrafluoroethylene (PTFE), using Ne, Kr and Xe as sputtering gases, were obtained and compared with prior spectra for SPTFE formed using He and Ar. The F/C (fluorine / carbon) ratios for SPTFE films (1.44-1.55), obtained at a rf power of 10 W, were essentially the same for all five rare gases, there being no trend of decreasing fluorine content in the SPTFE product with increasing atomic weight of the sputtering gas - contrary to the momentum transfer notion advanced by M. E. Ryan, et al. Increasing rf power from 10 to 50 W resulted in successively lower F/C ratios for SPTFE (e.g., from 1.55 to 1.21 in the case of Xe plasma-sputtered PTFE), accompanied by sputtering of the glass reactor and deposition of fragments of sodium aluminum silicate occurring at 40 W and above. In order to achieve a "Teflon-like" SPTFE structure (i.e., products with as high a F/C ratio as possible) in a given plasma reactor, an optimum rf power must be found, which in the present case was approximately 10 W.

  14. Study on re-sputtering during CN{sub x} film deposition through spectroscopic diagnostics of plasma

    SciTech Connect

    Liang, Peipei; Yang, Xu; Li, Hui; Cai, Hua; Sun, Jian; Xu, Ning; Wu, Jiada

    2015-10-15

    A nitrogen-carbon plasma was generated during the deposition of carbon nitride (CN{sub x}) thin films by pulsed laser ablation of a graphite target in a discharge nitrogen plasma, and the optical emission of the generated nitrogen-carbon plasma was measured for the diagnostics of the plasma and the characterization of the process of CN{sub x} film deposition. The nitrogen-carbon plasma was recognized to contain various species including nitrogen molecules and molecular ions excited in the ambient N{sub 2} gas, carbon atoms and atomic ions ablated from the graphite target and CN radicals. The temporal evolution and spatial distribution of the CN emission and their dependence on the substrate bias voltage show two groups of CN radicals flying in opposite directions. One represents the CN radicals formed as the products of the reactions occurring in the nitrogen-carbon plasma, revealing the reactive deposition of CN{sub x} film due to the reactive expansion of the ablation carbon plasma in the discharge nitrogen plasma and the effective formation of gaseous CN radicals as precursors for CN{sub x} film growth. The other one represents the CN radicals re-sputtered from the growing CN{sub x} film by energetic plasma species, evidencing the re-sputtering of the growing film accompanying film growth. And, the re-sputtering presents ion-induced sputtering features.

  15. Copper-induced dielectric breakdown in silicon oxide deposited by plasma-enhanced chemical vapor deposition using trimethoxysilane

    NASA Astrophysics Data System (ADS)

    Takeda, Ken-ichi; Ryuzaki, Daisuke; Mine, Toshiyuki; Hinode, Kenji; Yoneyama, Ryo

    2003-08-01

    The barrier mechanism against copper-ion diffusion in silicon-oxide films deposited by plasma-enhanced chemical vapor deposition (PECVD) using trimethoxysilane (TMS) and nitrous oxide (N2O) chemistry (PE-TMS oxide) was studied. It was found that the flow ratio of TMS gas to N2O gas during deposition strongly affects a time-dependent dielectric-breakdown lifetime of PE-TMS oxide with a copper electrode as well as other PE-TMS oxide film properties such as electrical properties (leakage current and dielectric constant), a physical property (atomic composition), and chemical properties (chemical bonding states and wet-etching rate). The dielectric-breakdown lifetime of PE-TMS oxide film with a copper anode is a maximum at a source-gas ratio ranging from 1.7% to 3.3%. On the other hand, leakage current density, wet-etch rate, and dielectric-breakdown lifetime of PE-TMS oxide film with an aluminum electrode are degraded by increasing the source-gas flow ratio (0.83% to 12%). These results suggest that two types of degradation mode exist in the dielectric breakdown of PE-TMS oxide with a copper electrode. Namely, at low flow ratio (<1.7%), copper-induced degradation is dominant, but at high flow ratio (>3.3%), the dielectric degradation is probably not caused by copper contamination but by low-quality dielectric material. The dielectric-breakdown lifetimes of a PE-TMS oxide film (flow ratio: 3.3%) with a copper anode show an Arrhenius-type temperature dependence. That is, the activation energy of the dielectric-breakdown lifetime depends on the applied electric field and decreases from 1.8 to 0.55 eV when the applied field is increased from 0 to 5 MV/cm. As a simple kinetic model of the copper injection reaction at the anode surface, a thermally activated reaction process between two energy states—copper atom state on the anode surface and copper ion state in the dielectric material—is proposed.

  16. Determination of titanium atom and ion densities in sputter deposition plasmas by optical emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Vašina, P.; Fekete, M.; Hnilica, J.; Klein, P.; Dosoudilová, L.; Dvořák, P.; Navrátil, Z.

    2015-12-01

    The thorough characterizations of deposition plasma lead to important achievements in the fundamental understanding of the deposition process, with a clear impact on the development of technology. Measurement of the spatial and, in the case of pulse excited plasma, also temporal evolution, of the concentrations of sputtered atoms and ions is a primary task in the diagnostics of any sputter deposition plasma. However, it is difficult to estimate absolute number densities of the sputtered species (atoms and ions) in ground states directly from optical emission spectroscopy, because the species in the ground levels do not produce any optical signal. A method using effective branching fractions enables us to determine the density of non-radiating species from the intensities of self-absorbed spectral lines. The branching fractions method described in the first part of this paper was applied to determine the ground state densities of the sputtered titanium atoms and ions. The method is based on fitting the theoretically calculated branching fractions to experimentally measured ratios of the relative intensities of carefully selected resonant titanium atomic and ionic lines. The sputtered species density is determined in our experimental setup with a relative uncertainty of less than 5% for the dc driven magnetron and typically 15% for time-resolved measurements of high-power impulse magnetron sputtering (HiPIMS) discharge. In the second part of the paper, the method was applied to determine the evolution of titanium atom and ion densities in three typical cases ranging from the dc driven sputter process to HiPIMS.

  17. Nanostructured bioactive glass-ceramic coatings deposited by the liquid precursor plasma spraying process

    NASA Astrophysics Data System (ADS)

    Xiao, Yanfeng; Song, Lei; Liu, Xiaoguang; Huang, Yi; Huang, Tao; Wu, Yao; Chen, Jiyong; Wu, Fang

    2011-01-01

    Bioactive glass-ceramic coatings have great potential in dental and orthopedic medical implant applications, due to its excellent bioactivity, biocompatibility and osteoinductivity. However, most of the coating preparation techniques either produce only thin thickness coatings or require tedious preparation steps. In this study, a new attempt was made to deposit bioactive glass-ceramic coatings on titanium substrates by the liquid precursor plasma spraying (LPPS) process. Tetraethyl orthosilicate, triethyl phosphate, calcium nitrate and sodium nitrate solutions were mixed together to form a suspension after hydrolysis, and the liquid suspension was used as the feedstock for plasma spraying of P 2O 5-Na 2O-CaO-SiO 2 bioactive glass-ceramic coatings. The in vitro bioactivities of the as-deposited coatings were evaluated by soaking the samples in simulated body fluid (SBF) for 4 h, 1, 2, 4, 7, 14, and 21 days, respectively. The as-deposited coating and its microstructure evolution behavior under SBF soaking were systematically analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP), and Fourier transform infrared (FTIR) spectroscopy. The results showed that P 2O 5-Na 2O-CaO-SiO 2 bioactive glass-ceramic coatings with nanostructure had been successfully synthesized by the LPPS technique and the synthesized coatings showed quick formation of a nanostructured HCA layer after being soaked in SBF. Overall, our results indicate that the LPPS process is an effective and simple method to synthesize nanostructured bioactive glass-ceramic coatings with good in vitro bioactivity.

  18. Deposition of Amorphous Silicon and Silicon-Based Dielectrics by Remote Plasma-Enhanced Chemical Vapor Deposition: Application to the Fabrication of Tft's and Mosfet's.

    NASA Astrophysics Data System (ADS)

    Kim, Sang Soo

    1990-01-01

    This thesis discusses the deposition of device quality silicon dioxide (SiO_2), silicon nitride (Si_3N_4 ), and hydrogenated amorphous silicon (a-Si:H) by the remote plasma enhanced chemical vapor deposition (Remote PECVD) technique at low substrate temperature (100 ^circC < T _{rm s} < 450^ circC). An ultra-high-vacuum (UHV) compatible, multi-chamber integrated processing system has been built and used for this study. This system provides: (1) in -situ substrate processing; (2) surface analysis by Auger electron spectroscopy (AES) and reflected high energy electron diffraction (RHEED); and (3) thin film deposition by Remote PECVD. Six issues are addressed: (1) in-situ semiconductor surface cleaning for Si, Ge, GaAs, and CdTe; (2) substrate surface characterization by using RHEED and AES; (3) process gas-substrate interactions (subcutaneous oxidation) occurring during the thin film deposition; (4) the thin film deposition process for silicon-based dielectrics and for doped and intrinsic amorphous silicon; (5) physical properties of the thin films deposited by Remote PECVD using in-situ AES, and ex-situ infrared (ir) spectroscopy and ellipsometry; and (6) electrical performance of thin films in device structures including metal-oxide/or insulator-semiconductor (MOS or MIS) capacitors formed on silicon, and hydrogenated -amorphous silicon thin film transistors (a-Si:H TFT's). Atomically clean semiconductor surfaces are obtained by a remote hydrogen plasma treatment prior to thin film deposition. In the remote PECVD process the process gases are selectively excited, the silane reactant, the source of silicon atoms in the films is never directly plasma excited, and the substrate is also remote from the plasma discharge region. These differences between the remote PECVD process and the conventional direct PECVD process, result in improved control of the insulator stoichiometry, and a reduction in level of chemical impurities such as hydrogen. We find that the

  19. Influence of plasma spraying deposition process on optical properties of hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Belka, Radosław; Kowalski, Szymon; Żórawski, Wojciech; Suchańska, Małgorzata

    2015-09-01

    Hydroxyapatite (HAp) is a well-known bioceramic, nonorganic material of the bones of the vertebrate responsible for their mechanical durability. In human bones it occupies 60-80 % of the volume depending on a number of factors. Synthetic HAp is valued in bone endoprosthetic to its high biocompatibility. It is widely used to fill cavities of bone and as the coating of bone implants to increase their biocompatibility and adhesion to bone surface. In this paper a diffuse reflectance spectra of plasma-spraying deposited hydroxyapatite were presented and compared with pure powder samples. Optical band gap were estimated basing on Kubelka-Munk functions and Tauc plot extrapolation. We found that deposition process affects the value of band gap.

  20. NiCrSiB Coatings Deposited by Plasma Transferred Arc on Different Steel Substrates

    NASA Astrophysics Data System (ADS)

    Reinaldo, P. R.; D'Oliveira, A. S. C. M.

    2013-02-01

    Colmonoy 6 (NiCrSiB) is a Ni-based alloy recognized for its superior mechanical properties, attributed to the presence of a dispersion of hard carbides and borides, which is strongly dependent on processing technique. This work gathered microstructure data from the literature and analyzed Colmonoy 6 coatings deposited by plasma transferred arc hardfacing. The aim of the study was to determine the influence of PTA deposition parameters and substrate chemical composition on NiCrSiB coating characteristics. Coatings were characterized in terms of their hardness, dilution, and microstructure, as well as mass loss during abrasive sliding wear tests. The results showed that coating performance is strongly dependent on the chemical composition of the substrate. Carbon steel substrate yielded coatings with greater wear resistance. Processing parameters also alter the performance of coatings, and the lower current and lower travel speed result in reduced mass loss.

  1. Oxygen-poor phase observed during plasma-sprayed physical vapor deposition of zirconia coatings

    NASA Astrophysics Data System (ADS)

    Good, Brian; Harder, Bryan

    2014-03-01

    When cubic zirconia is deposited using Plasma Spray-Physical Vapor Deposition (PS-PVD) under oxygen-poor conditions, a metastable phase is observed. We describe a combined experimental and computational approach aimed at determining the structure and composition of the phase. X-Ray analysis indicates that the phase exhibits cubic symmetry, and it is also found to be electrically conductive, in contrast to cubic zirconia, which is electrically insulating. We have performed electronic structure calculations aimed at identifying the metastable phase. Three cubic candidate ZrO structures were identified, and the lattice constants were optimized for each. The lowest-energy structure was found to be the NaCl structure. Projected density of states calculations show that the material is conductive, with conduction occurring within the Zr 4s band. Potential technological uses for the phase are discussed.

  2. Deposition of superhydrophobic nanostructured Teflon-like coating using expanding plasma arc

    NASA Astrophysics Data System (ADS)

    Satyaprasad, A.; Jain, V.; Nema, S. K.

    2007-04-01

    A novel approach was used to grow nanostructured Teflon-like superhydrophobic coatings on stainless steel (SS). In this method Teflon tailings were pyrolyzed to generate fluorocarbon precursor molecules, and an expanding plasma arc (EPA) was used to polymerize these precursors to deposit Teflon-like coating. The coating shows super hydrophobic behavior with water contact angle (WCA) of 165°. The coating was observed to be uniform. It consists of nanostructured (˜80-200 nm) features, which were confirmed by scanning electron microscopy. The chemical bond state of the film was determined by XPS and FTIR, which indicate the dominance of -CF 2 groups in the deposited coating. The combination of nanofeature induced surface roughness and the low surface energy imparted by Teflon-like coating is responsible for the observed superhydrophobic nature.

  3. Plasma deposited hydrogenated carbon on GaAs and InP

    NASA Technical Reports Server (NTRS)

    Warner, J. D.; Pouch, J. J.; Alterovitz, S. A.; Liu, D. C.; Lanford, W. A.

    1985-01-01

    The properties of diamond like carbon films grown by RF flow discharge 30 kHz plasma using methane are reported. The Cis XPS line shape of films showed localized hybrid carbon bonds as low as 40 to as high as 95 percent. Infrared spectroscopy and N(15) nuclear reaction profiling data indicated 35 to 42 percent hydrogen, depending inversely on deposition temperature. The deposition rate of films on Si falls off exponentially with substrate temperature, and nucleation does not occur above 200 C on GaAs and InP. Optical data of the films showed bandgap values of 2.0 to 2.4 eV increasing monotonically with CH4 flow rate.

  4. Plasma deposited diamondlike carbon on GaAs and InP

    NASA Technical Reports Server (NTRS)

    Warner, J. D.; Pouch, J. J.; Alterovitz, S. A.; Liu, D. C.; Lanford, W. A.

    1984-01-01

    The properties of diamond like carbon films grown by RF flow discharge 30 kHz plasma using methane are reported. The Cls XPS line shape of films showed localized hybrid carbon bonds as low as 40 to as high as 95 percent. Infrared spectroscopy and N(15) nuclear reaction profiling data indicated 35 to 42 percent hydrogen, depending inversely on deposition temperature. The deposition rate of films on Si falls off exponentially with substrate temperature, and nucleation does not occur above 200 C on GaAs and InP. Optical data of the films showed bandgap values of 2.0 to 2.4 eV increasing monotonically with CH4 flow rate.

  5. Tungsten-doped tin oxide thin films prepared by pulsed plasma deposition

    SciTech Connect

    Huang Yanwei; Zhang Qun Li Guifeng; Yang Ming

    2009-05-15

    Transparent conductive oxide tungsten-doped tin oxide thin films were deposited on glass substrates from ceramic targets by the pulsed plasma deposition method. The structural, electrical and optical properties have been investigated as functions of tungsten doping content and oxygen partial pressure. The lowest resistivity of 2.1 x 10{sup -3} {omega}{center_dot}cm was reproducibly obtained, with carrier mobility of 30 cm{sup 2}V{sup -1}s{sup -1} and carrier concentration of 9.6 x 10{sup 19} cm{sup -3} at the oxygen partial pressure of 1.8 Pa. The average optical transmission was in excess of 80% in the visible region from 400 to 700 nm, with the optical band gap ranging from 3.91 to 4.02 eV.

  6. Ground State and Excited State H-Atom Temperatures in a Microwave Plasma Diamond Deposition Reactor

    NASA Astrophysics Data System (ADS)

    Gicquel, A.; Chenevier, M.; Breton, Y.; Petiau, M.; Booth, J. P.; Hassouni, K.

    1996-09-01

    Ground electronic state and excited state H-atom temperatures are measured in a microwave plasma diamond deposition reactor as a function of a low percentage of methane introduced in the feed gas and the averaged input microwave power density. Ground state H-atom temperatures (T_H) and temperature of the H-atom in the n=3 excited state (T_{Hα}) are obtained from the measurements respectively of the excitation profile by Two-photon Allowed transition Laser Induced Fluorescence (TALIF) and the Hα line broadening by Optical Emission Spectroscopy (OES). They are compared to gas temperatures calculated with a 1D diffusive non equilibrium H{2} plasma flow model and to ground electronic state rotational temperatures of molecular hydrogen measured previously by Coherent Anti-Stokes Raman Spectroscopy.

  7. Single-electron devices fabricated using double-angle deposition and plasma oxidation

    NASA Astrophysics Data System (ADS)

    Hong, Y.; Barcikowski, Z. S.; Ramanayaka, A. N.; Stewart, M. D., Jr.; Zimmerman, N. M.; Pomeroy, J. M.; Quantum Processes; Metrology Group Team

    We report on development of plasma oxidized, single-electron transistors (SETs) where we seek low-capacitance and small-area Al/AlOx/Al tunnel junctions with small charge offset drift. Performance of metal-based SET quantum devices and superconducting devices has suffered from long-term charge offset drift, high defect densities and charge noise. We use plasma oxidation to lower defect densities of the oxide layer, and adjustable deposition angles to control the overlapping areas for Al/AlOx/Al tunnel junctions. Current-voltage and charge offset drift measurements are planned for cryogenic temperatures. Other electrical properties will be measured at room temperature. We hope to see Coulomb blockade oscillations on these devices and better charge offset stability than typical Al/AlOx/Al SETs.

  8. Fabrication of Nanosized Lanthanum Zirconate Powder and Deposition of Thermal Barrier Coating by Plasma Spray Process

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Jagdeesh, N.; Pathak, L. C.

    2016-07-01

    The present manuscript discusses our findings on fabrication of nanosized lanthanum zirconate powder for thermal barrier coating application and its coating by plasma spray on nickel-based superalloy substrate. Single-phase La2Zr2O7 coating of thickness of the order of 45 µm on the Ni-Cr-Al bond coat coated Ni-based superalloy substrate was deposited by plasma spray process. The layers at the interface did not show spallation and inter diffusion was very less. The microstructure, interface, porosity, and mechanical properties of different layers are investigated. The lanthanum zirconate hardness and modulus were 10.5 and 277 GPa, respectively. The load depth curve for lanthanum zirconate showed good elastic recovery around 74%.

  9. Properties of AlN films deposited by reactive ion-plasma sputtering

    SciTech Connect

    Bert, N. A.; Bondarev, A. D.; Zolotarev, V. V.; Kirilenko, D. A.; Lubyanskiy, Ya. V.; Lyutetskiy, A. V.; Slipchenko, S. O.; Petrunov, A. N.; Pikhtin, N. A. Ayusheva, K. R.; Arsentyev, I. N.; Tarasov, I. S.

    2015-10-15

    The properties of SiO{sub 2}, Al{sub 2}O{sub 3}, and AlN dielectric coatings deposited by reactive ion-plasma sputtering are studied. The refractive indices of the dielectric coatings are determined by optical ellipsometry. It is shown that aluminum nitride is the optimal material for achieving maximum illumination of the output mirror of a semiconductor laser. A crystalline phase with a hexagonal atomic lattice and oxygen content of up to 10 at % is found by transmission electron microscopy in the aluminum-nitride films. It is found that a decrease in the concentration of residual oxygen in the chamber of the reactive ion-plasma sputtering installation makes it possible to eliminate the appearance of vertical pores in the bulk of the aluminum-nitride film.

  10. Graphene layer growth on silicon substrates with nickel film by pulse arc plasma deposition

    SciTech Connect

    Fujita, K.; Banno, K.; Aryal, H. R.; Egawa, T.

    2012-10-15

    Carbon layer has been grown on a Ni/SiO{sub 2}/Si(111) substrate under high vacuum pressure by pulse arc plasma deposition. From the results of Raman spectroscopy for the sample, it is found that graphene was formed by ex-situ annealing of sample grown at room temperature. Furthermore, for the sample grown at high temperature, graphene formation was shown and optimum temperature was around 1000 Degree-Sign C. Transmission electron microscopy observation of the sample suggests that the graphene was grown from step site caused by grain of Ni film. The results show that the pulse arc plasma technique has the possibility for acquiring homogenous graphene layer with controlled layer thickness.

  11. Microstructures of Yttria-Stabilized Zirconia Coatings by Plasma Spray-Physical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Li, Chenyi; Guo, Hongbo; Gao, Lihua; Wei, Liangliang; Gong, Shengkai; Xu, Huibin

    2015-02-01

    As a novel processing technology, plasma spray-physical vapor deposition (PS-PVD) has exhibited potential capability to shape the sprayed coating microstructures. In this paper, yttria-stabilized zirconia (YSZ) coatings were produced at spray distances in the range of 450-1400 mm by PS-PVD. The morphologies of the coatings, going from a denser type of layer to the columnar structure, along the axial and radial directions of the plasma plume were studied. Along the axial direction, five YSZ coating microstructures including "dense lamellar structure," "closely packed columnar structure," "quasi-columnar structure with more nanoparticles," "EB-PVD-like columnar structure," and "quasi-columnar structure with less nanoparticles" were achieved, respectively. Along the radial direction, similar microstructures of coatings were obtained. A simple structure spatial distribution model was developed for demonstrating the mapping of various YSZ coating microstructures.

  12. Nickel doping of boron carbide grown by plasma enhanced chemical vapor deposition

    SciTech Connect

    Hwang, S.; Remmes, N.B.; Dowben, P.A.; McIlroy, D.N.

    1996-07-01

    We have nickel doped boron carbide grown by plasma enhanced chemical vapor deposition. The source gas closo-1,2-dicarbadodecaborane (ortho-carborane) was used to grow the boron carbide, while nickelocene [Ni(C{sub 5}H{sub 5}){sub 2}] was used to introduce nickel into the growing film. The doping of nickel transformed a {ital p}-type, B{sub 5}C material, relative to lightly doped {ital n}-type silicon, to an {ital n}-type material. Both {ital n}-{ital n} heterojunction diodes and {ital n}-{ital p} heterojunction diodes were constructed, using as substrates {ital n}- and {ital p}-type Si(111), respectively. With sufficient partial pressures of nickelocene in the plasma reactor, diodes with characteristic tunnel diode behavior can be successfully fabricated. {copyright} {ital 1996 American Vacuum Society}

  13. MHD Modelling of Flow Phenomena during the Impulse Plasma Deposition Process

    NASA Astrophysics Data System (ADS)

    Rabiński, M.; Zdunek, K.

    2008-03-01

    The paper presents recent computational studies of plasma dynamics in a coaxial accelerator used in surface engineering for Impulse Plasma Deposition (IPD). In our earlier studies we proposed a schematic pattern of a discharge region and a physical model of dynamic phenomena in the IPD accelerator with a tubular external electrode. The simplified snow plow code of our previous studies assumes that all the swept up mass is compressed into an infinitely thin layer immediately behind the shock. In the presented work the complete two-dimensional two-fluid magnetohydrodynamic model has been applied to investigate the sweeping of the working gas by the moving layer as well as the details of phenomena that take place behind a current sheet.

  14. Synthesis of carbon nanowall by plasma-enhanced chemical vapor deposition method.

    PubMed

    Liu, Rulin; Chi, Yaqing; Fang, Liang; Tang, Zhensen; Yi, Xun

    2014-02-01

    Plasma-enhanced chemical vapor deposition (PECVD) is widely used for the synthesis of carbon materials, such as diamond-like carbons (DLCs), carbon nanotubes (CNTs) and carbon nanowalls (CNWs). Advantages of PECVD are low synthesis temperature compared with thermal CVD and the ability to grow vertically, free-standing structures. Due to its self-supported property and high specific surface area, CNWs are a promising material for field emission devices and other chemical applications. This article reviews the recent process on the synthesis of CNW by the PECVD method. We briefly introduce the structure and properties of CNW with characterization techniques. Growth mechanism is also discussed to analyze the influence of plasma conditions, substrates, temperature, and other parameters to the final film, which will give a suggestion on parameter modulation for desired film. PMID:24749447

  15. Fabrication of Nanosized Lanthanum Zirconate Powder and Deposition of Thermal Barrier Coating by Plasma Spray Process

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Jagdeesh, N.; Pathak, L. C.

    2016-05-01

    The present manuscript discusses our findings on fabrication of nanosized lanthanum zirconate powder for thermal barrier coating application and its coating by plasma spray on nickel-based superalloy substrate. Single-phase La2Zr2O7 coating of thickness of the order of 45 µm on the Ni-Cr-Al bond coat coated Ni-based superalloy substrate was deposited by plasma spray process. The layers at the interface did not show spallation and inter diffusion was very less. The microstructure, interface, porosity, and mechanical properties of different layers are investigated. The lanthanum zirconate hardness and modulus were 10.5 and 277 GPa, respectively. The load depth curve for lanthanum zirconate showed good elastic recovery around 74%.

  16. Fabrication of nanocrystalline silicon layers by plasma enhanced chemical vapor deposition from silicon tetrafluoride

    SciTech Connect

    Sennikov, P. G. Golubev, S. V.; Shashkin, V. I.; Pryakhin, D. A.; Drozdov, M. N.; Andreev, B. A.; Drozdov, Yu. N.; Kuznetsov, A. S.; Pohl, H.-J.

    2009-07-15

    The data on fabrication of silicon layers on various substrates by plasma enhanced chemical vapor deposition from the (silicon tetrafluoride)-hydrogen system are reported. The emission spectra of the plasma in the system are recorded. The samples were studied by the X-ray diffraction and secondary ion mass spectrometry techniques. The morphologic properties of the surface are examined, and the Raman spectra, the transmittance spectra in the infrared region, and photoluminescence spectra are recorded. The phase composition of the layers corresponds to nanocrystalline silicon, in which the dimensions of coherent-scattering grains vary with the conditions of the preparation process in the range from 3 to 9 nm. The layers exhibit intense photoluminescence at room temperature.

  17. Energy deposition and thermal effects of runaway electrons in ITER-FEAT plasma facing components

    NASA Astrophysics Data System (ADS)

    Maddaluno, G.; Maruccia, G.; Merola, M.; Rollet, S.

    2003-03-01

    The profile of energy deposited by runaway electrons (RAEs) of 10 or 50 MeV in International Thermonuclear Experimental Reactor-Fusion Energy Advanced Tokamak (ITER-FEAT) plasma facing components (PFCs) and the subsequent temperature pattern have been calculated by using the Monte Carlo code FLUKA and the finite element heat conduction code ANSYS. The RAE energy deposition density was assumed to be 50 MJ/m 2 and both 10 and 100 ms deposition times were considered. Five different configurations of PFCs were investigated: primary first wall armoured with Be, with and without protecting CFC poloidal limiters, both port limiter first wall options (Be flat tile and CFC monoblock), divertor baffle first wall, armoured with W. The analysis has outlined that for all the configurations but one (port limiter with Be flat tile) the heat sink and the cooling tube beneath the armour are well protected for both RAE energies and for both energy deposition times. On the other hand large melting (W, Be) or sublimation (C) of the surface layer occurs, eventually affecting the PFCs lifetime.

  18. The Mechanical Properties of Alumina Films Formed by Plasma Deposition and by Ion Irradiation of Sapphire

    SciTech Connect

    Barbour, J.C.; Follstaedt, D.M.; Knapp, J.A.; Linam, D.L.; Mayer, T.M.; Minor, K.G.

    1999-07-16

    This paper examines the correlation between mechanical properties and the density, phase, and hydrogen content of deposited alumina layers, and compares them to those of sapphire and amorphous alumina synthesized through ion-beam irradiation of sapphire. Alumina films were deposited using electron beam evaporation of aluminum and co-bombardment with O{sub 2}{sup +} ions (30-230 eV) from an electron cyclotron resonance (ECR) plasma. The H content and phase were controlled by varying the deposition temperature and the ion energy. Sapphire was amorphized at 84 K by irradiation with Al and O ions (in stoichiometric ratio) to a defect level of 4 dpa in order to form an amorphous layer 370 nm thick. Nanoindentation was performed to determine the elastic modulus, yield strength and hardness of all materials. Sapphire and amorphized sapphire have a higher density and exhibit superior mechanical properties in comparison to the deposited alumina films. Density was determined to be the primary factor affecting the mechanical properties, which showed only a weak correlation to the hydrogen content.

  19. Plasma enhanced chemical vapor deposition of silicon oxide films with divinyldimethylsilane and tetravinylsilane

    SciTech Connect

    Park, Sung-Gyu; Rhee, Shi-Woo

    2006-03-15

    Carbon-doped silicon oxide (SiCOH) low-k films were deposited with plasma enhanced chemical vapor deposition (PECVD) using divinyldimethylsilane (DVDMS) with two vinyl groups and tetravinylsilane (TVS) with four vinyl groups compared with vinyltrimethylsilane (VTMS) with one vinyl group. With more vinyl groups in the precursor, due to the crosslinking of the vinyl groups, the film contains more of an organic phase and organic phase became less volatile. It was confirmed that the deposition rate, refractive index, and k value increase with more vinyl groups in the precursor molecule. After annealing, the SiCOH films deposited with DVDMS and TVS showed a low dielectric constant of 2.2 and 2.4 at optimum conditions, respectively. In both cases, the annealed film had low leakage current density (J=6.7x10{sup -7} A/cm{sup 2} for SiCOH film of DVDMS and J=1.18x10{sup -8} A/cm{sup 2} for SiCOH film of TVS at 1 MV/cm) and relatively high breakdown field strength (E>4.0 MV/cm at 1 mA/cm{sup 2}), which is comparable to those of PECVD SiO{sub 2}.

  20. Low-Energy Plasma Spray (LEPS) Deposition of Hydroxyapatite/Poly-ɛ-Caprolactone Biocomposite Coatings

    NASA Astrophysics Data System (ADS)

    Garcia-Alonso, Diana; Parco, Maria; Stokes, Joseph; Looney, Lisa

    2012-01-01

    Thermal spraying is widely employed to deposit hydroxyapatite (HA) and HA-based biocomposites on hip and dental implants. For thick HA coatings (>150 μm), problems are generally associated with the build-up of residual stresses and lack of control of coating crystallinity. HA/polymer composite coatings are especially interesting to improve the pure HA coatings' mechanical properties. For instance, the polymer may help in releasing the residual stresses in the thick HA coatings. In addition, the selection of a bioresorbable polymer may enhance the coatings' biological behavior. However, there are major challenges associated with spraying ceramic and polymeric materials together because of their very different thermal properties. In this study, pure HA and HA/poly-ɛ-caprolactone (PCL) thick coatings were deposited without significant thermal degradation by low-energy plasma spraying (LEPS). PCL has never been processed by thermal spraying, and its processing is a major achievement of this study. The influence of selected process parameters on microstructure, composition, and mechanical properties of HA and HA/PCL coatings was studied using statistical design of experiments (DOE). The HA deposition rate was significantly increased by the addition of PCL. The average porosity of biocomposite coatings was slightly increased, while retaining or even improving in some cases their fracture toughness and microhardness. Surface roughness of biocomposites was enhanced compared with HA pure coatings. Cell culture experiments showed that murine osteoblast-like cells attach and proliferate well on HA/PCL biocomposite deposits.

  1. Effect of Low-Energy Ions on Plasma-Enhanced Deposition of Cubic Boron Nitride

    NASA Astrophysics Data System (ADS)

    Torigoe, M.; Fukui, S.; Teii, K.; Matsumoto, S.

    2015-09-01

    The effect of low-energy ions on deposition of cubic boron nitride (cBN) films in an inductively coupled plasma with the chemistry of fluorine is studied in terms of ion energy, ion flux, and ion to boron flux ratio onto the substrate. The ion energy and the ion to boron flux ratio are determined from the sheath potential and the ratio of incident ion flux to net deposited boron flux, respectively. For negative substrate biases where sp2-bonded BN phase only or no deposit is formed, both the ion energy and the ion to boron flux ratio are high. For positive substrate biases where cBN phase is formed, the ion energy and the ion to boron flux ratio are estimated in the range of a few eV to 35 eV and 100 to 130, respectively. The impact of negative ions is presumed to be negligible due to their low kinetic energy relative to the sheath potential over the substrate surface. The impact of positive ions with high ion to boron flux ratios is primarily responsible for reduction of the ion energy for cBN film deposition. Work supported in part by a Grant-in-Aid for Scientific Research (B), a Funding Program for Next Generation World-Leading Researchers, and an Industrial Technology Research Grant Program 2008.

  2. Local bonding environment of plasma deposited nitrogen-rich silicon nitride thin films

    NASA Astrophysics Data System (ADS)

    Soh, Martin T. K.; Savvides, N.; Musca, Charles A.; Martyniuk, Mariusz P.; Faraone, Lorenzo

    2005-05-01

    Plasma deposited nitrogen-rich silicon nitride thin films were prepared at temperatures between 80 and 300 °C. The infrared transmission (400-4000cm-1) was measured, and selected absorption bands were quantified through a multiple Lorentzian oscillator parametric analysis. It is observed that the concentration of silicon-centered tetrahedra bonded together through nitrogen atoms increases monotonically with increasing deposition temperature. A qualitative model is presented to highlight the impact of the active adsorption site density on the degree of stepped (ordered) nucleation at the vapor-film interface. The importance of this growth profile, in particular for micro-systems-technology, is discussed in conjunction with measurements of the biaxial modulus and residual stress of the thin films. A mechanism for residual stress controllability is also presented. The atomic concentrations of silicon, nitrogen, and hydrogen in the thin films were calculated using infrared calibration factors derived from the deposition temperature dependent condensation processes. The results for silicon nitride thin films deposited at 300 °C were observed to be similar in composition to silicon diimide. Additional observations of the infrared transmission characteristics are reported, which include the identification of silazane bridge characteristics for the absorption feature around 610cm-1, which is typically associated with Si-H (bending) absorption.

  3. Effects of Plasma Polymer Films and Their Deposition Powers on the Barrier Characteristics of the Multilayer Encapsulation for Organic Devices.

    PubMed

    Kim, Hoonbae; Ban, Wonjin; Kwon, Sungruel; Yong, Sanghyun; Chae, Heeyeop; Jung, Donggeun

    2016-05-01

    Organic electronic devices (OEDs) are quite suitable for use in flexible devices due to their ruggedness and flexibility. A number of researchers have studied the use of OEDs on flexible substrates in transparent, flexible devices in the near future. However, water and oxygen can permeate through the flexible substrates and can reduce the longevity of OEDs made from organic materials, which are weak to moisture and oxygen. In order to prevent the degradation of the OEDs, researchers have applied an encapsulation layer to the flexible substrates. In this study, Al2O3/plasma polymer film/Al2O3 multi-layers were deposited on polyethylene-naphthalate substrates through a combination of atomic layer deposition and plasma-enhanced chemical vapor deposition (PECVD). The plasma polymer film, which is located between the Al2O3 films, is deposited via PECVD with the use of a tetrakis(trimethylsilyloxy)silane precursor. The power of the plasma deposition varied from 10 to 50 W. The hydrophobicity of the plasma polymer film surfaces was investigated by measuring the water contact angle. The chemical structures of the plasma polymer films were measured via ex-situ Fourier transform infrared analysis. The permeation curves of the various films were analyzed by performing a calcium (Ca)-test. PMID:27483936

  4. Mechanisms of degradation and failure in a plasma deposited thermal barrier coating

    NASA Technical Reports Server (NTRS)

    Demasi-Marcin, Jeanine T.; Sheffler, Keith D.; Bose, Sudhangshu

    1989-01-01

    Failure of a two layer plasma deposited thermal barrier coating is caused by cyclic thermal exposure and occurs by spallation of the outer ceramic layer. Spallation life is quantitatively predictable, based on the severity of cyclic thermal exposure. This paper describes and attempts to explain unusual constitutive behavior observed in the insulative ceramic coating layer, and presents details of the ceramic cracking damage accumulation process which is responsible for spallation failure. Comments also are offered to rationalize the previously documented influence of interfacial oxidation on ceramic damage accumulation and spallation life.

  5. The reaction pathways of the oxygen plasma pulse in the hafnium oxide atomic layer deposition process

    SciTech Connect

    Jeon, Hyeongtag; Won, Youngdo

    2008-09-22

    The plasma enhanced atomic layer deposition process for the HfO{sub 2} thin film is modeled as simple reactions between Hf(OH){sub 3}NH{sub 2} and reactive oxygen species. The density functional theory calculation was performed for plausible reaction pathways to construct the reaction profile. While the triplet molecular oxygen is unlikely to form a reactive complex, the singlet molecular oxygen forms the stable adduct that goes through the transition state and completes the reaction pathway to the products. Either two singlet or two triplet oxygen atoms make the singlet adduct complex, which follows the same pathway to the product as the singlet molecular oxygen reacts.

  6. High T(sub c) superconductors fabricated by plasma aerosol mist deposition technique

    NASA Technical Reports Server (NTRS)

    Wang, X. W.; Vuong, K. D.; Leone, A.; Shen, C. Q.; Williams, J.; Coy, M.

    1995-01-01

    We report new results on high T(sub c) superconductors fabricated by a plasma aerosol mist deposition technique, in atmospheric environment. Materials fabricated are YBaCuO, BiPbSrCaCuO, BaCaCuO precursor films for TlBaCaCuO, and other buffers such as YSZ. Depending on processing conditions, sizes of crystallites and/or particles are between dozens of nano-meters and several micrometers. Superconductive properties and other material characteristics can also be tailored.

  7. Feather-like Structured YSZ Coatings at Fast Rates by Plasma Spray Physical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Shinozawa, A.; Eguchi, K.; Kambara, M.; Yoshida, T.

    2010-01-01

    A variety of yttria-stabilized zirconia (YSZ) coatings have been attained by plasma spray physical vapor deposition (PS-PVD) with fine YSZ powders at high power. The coating structures were found to change significantly with the powder feeding rates but less with the substrate temperature and the rate of the substrate rotation, and a porous feather like structure was attained at 500 Torr (666.6 millibar) and a rate of >200 μm/min. Such a coating produces porosity reaching >50%, thermal conductivity as small as 0.5 W/mK and lower infra-red transmittance compared to the sprayed splat coating with identical thickness.

  8. Laser surface modification of electroplated, physically vapor deposited and plasma sprayed coatings

    SciTech Connect

    Dini, J.W.

    1996-05-01

    Lasers are used to modify surface characteristics in order to improve properties for a variety of industrial applications. Typical surface alterations include: transformation hardening, melting, cladding, alloying, coating, and smoothing. This paper is a critical review that covers surface alloying. It concentrates on coatings applied by electroplating, plasma spraying or physical vapor deposition and the resultant properties obtained after laser treatment. In many cases, significant improvement in properties such as corrosion resistance, wear resistance, creep strength, porosity, and structure was noted after coatings were exposed to a laser treatment. 112 refs., 12 figs., 4 tabs.

  9. Plasma-enhanced atomic layer deposition and etching of high-k gadolinium oxide

    SciTech Connect

    Vitale, Steven A.; Wyatt, Peter W.; Hodson, Chris J.

    2012-01-15

    Atomic layer deposition (ALD) of high-quality gadolinium oxide thin films is achieved using Gd(iPrCp){sub 3} and O{sub 2} plasma. Gd{sub 2}O{sub 3} growth is observed from 150 to 350 deg. C, though the optical properties of the film improve at higher temperature. True layer-by-layer ALD growth of Gd{sub 2}O{sub 3} occurred in a relatively narrow window of temperature and precursor dose. A saturated growth rate of 1.4 A/cycle was observed at 250 deg. C. As the temperature increases, high-quality films are deposited, but the growth mechanism appears to become CVD-like, indicating the onset of precursor decomposition. At 250 deg. C, the refractive index of the film is stable at {approx}1.80 regardless of other deposition conditions, and the measured dispersion characteristics are comparable to those of bulk Gd{sub 2}O{sub 3}. XPS data show that the O/Gd ratio is oxygen deficient at 1.3, and that it is also very hygroscopic. The plasma etching rate of the ALD Gd{sub 2}O{sub 3} film in a high-density helicon reactor is very low. Little difference is observed in etching rate between Cl{sub 2} and pure Ar plasmas, suggesting that physical sputtering dominates the etching. A threshold bias power exists below which etching does not occur; thus it may be possible to etch a metal gate material and stop easily on the Gd{sub 2}O{sub 3} gate dielectric. The Gd{sub 2}O{sub 3} film has a dielectric constant of about 16, exhibits low C-V hysteresis, and allows a 50 x reduction in gate leakage compared to SiO{sub 2}. However, the plasma enhanced atomic layer deposition (PE-ALD) process causes formation of an {approx}1.8 nm SiO{sub 2} interfacial layer, and generates a fixed charge of -1.21 x 10{sup 12} cm{sup -2}, both of which may limit use of PE-ALD Gd{sub 2}O{sub 3} as a gate dielectric.

  10. Fabrication of transparent antifouling thin films with fractal structure by atmospheric pressure cold plasma deposition.

    PubMed

    Miyagawa, Hayato; Yamauchi, Koji; Kim, Yoon-Kee; Ogawa, Kazufumi; Yamaguchi, Kenzo; Suzaki, Yoshifumi

    2012-12-21

    Antifouling surface with both superhydrophobicity and oil-repellency has been fabricated on glass substrate by forming fractal microstructure(s). The fractal microstructure was constituted by transparent silica particles of 100 nm diameter and transparent zinc-oxide columns grown on silica particles by atmospheric pressure cold plasma deposition. The sample surface was coated with a chemically adsorbed monomolecular layer. We found that one sample has the superhydrophobic ability with a water droplet contact angle of more than 150°, while another sample has a high transmittance of more than 85% in a wavelength range from 400 to 800 nm. PMID:23186100

  11. Fabrication of Carbon Nanotube Field Effect Transistors Using Plasma-Enhanced Chemical Vapor Deposition Grown Nanotubes

    NASA Astrophysics Data System (ADS)

    Ohnaka, Hirofumi; Kojima, Yoshihiro; Kishimoto, Shigeru; Ohno, Yutaka; Mizutani, Takashi

    2006-06-01

    Single-walled carbon nanotubes are grown using grid-inserted plasma-enhanced chemical vapor deposition (PECVD). The field effect transistor operation was confirmed using the PECVD grown carbon nanotubes (CNTs). The preferential growth of the semiconducting nanotubes was confirmed in the grid-inserted PECVD by measuring current-voltage (I-V) characteristics of the devices. Based on the measurement of the electrical breakdown of the metallic CNTs, the probability of growing the semiconducting nanotubes has been estimated to be more than 90%.

  12. Studies on non-oxide coating on carbon fibers using plasma enhanced chemical vapor deposition technique

    NASA Astrophysics Data System (ADS)

    Patel, R. H.; Sharma, S.; Prajapati, K. K.; Vyas, M. M.; Batra, N. M.

    2016-05-01

    A new way of improving the oxidative behavior of carbon fibers coated with SiC through Plasma Enhanced Chemical Vapor Deposition technique. The complete study includes coating of SiC on glass slab and Stainless steel specimen as a starting test subjects but the major focus was to increase the oxidation temperature of carbon fibers by PECVD technique. This method uses relatively lower substrate temperature and guarantees better stoichiometry than other coating methods and hence the substrate shows higher resistance towards mechanical and thermal stresses along with increase in oxidation temperature.

  13. Plasma-deposited fluoropolymer film mask for local porous silicon formation

    NASA Astrophysics Data System (ADS)

    Defforge, Thomas; Capelle, Marie; Tran-Van, François; Gautier, Gaël

    2012-06-01

    The study of an innovative fluoropolymer masking layer for silicon anodization is proposed. Due to its high chemical resistance to hydrofluoric acid even under anodic bias, this thin film deposited by plasma has allowed the formation of deep porous silicon regions patterned on the silicon wafer. Unlike most of other masks, fluoropolymer removal after electrochemical etching is rapid and does not alter the porous layer. Local porous regions were thus fabricated both in p+-type and low-doped n-type silicon substrates.

  14. Model of enhanced energy deposition in a Z-pinch plasma

    SciTech Connect

    Velikovich, A. L.; Davis, J.; Thornhill, J. W.; Giuliani, J. L. Jr.; Rudakov, L. I.; Deeney, C.

    2000-08-01

    In numerous experiments, magnetic energy coupled to strongly radiating Z-pinch plasmas exceeds the thermalized kinetic energy, sometimes by a factor of 2-3. An analytical model describing this additional energy deposition based on the concept of macroscopic magnetohydrodynamic (MHD) turbulent pinch heating proposed by Rudakov and Sudan [Phys. Reports 283, 253 (1997)] is presented. The pinch plasma is modeled as a foam-like medium saturated with toroidal ''magnetic bubbles'' produced by the development of surface m=0 Rayleigh-Taylor and MHD instabilities. As the bubbles converge to the pinch axis, their magnetic energy is converted to thermal energy of the plasma through pdV work. Explicit formulas for the average dissipation rate of this process and the corresponding contribution to the resistance of the load, which compare favorably to the experimental data and simulation results, are presented. The possibility of using this enhanced (relative to Ohmic heating) dissipation mechanism to power novel plasma radiation sources and produce high K-shell yields using long current rise time machines is discussed. (c) 2000 American Institute of Physics.

  15. Morphological evolution of self-deposition Bi2Se3 nanosheets by oxygen plasma treatment

    PubMed Central

    Jia, Guozhi; Wu, Zengna; Wang, Peng; Yao, Jianghong; Chang, Kai

    2016-01-01

    Bi2Se3 nanosheets were successfully synthesized by a microwave-assisted approach in the presence of polyvinylpyrroli done at a temperature of 180 °C for 2 h. The thin film was prepared on a silicon wafer via a self-deposition process in a Bi2Se3 nanosheet ink solution using the evaporation-induced self-assembly method. The structure and morphology of the obtained products were characterized by X-ray diffraction, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy, and Raman spectroscopy. The highly uniform Bi2Se3 particles could be formed by controlling the oxygen plasma treatment time. After the plasma pretreatment from 10 to 20 s, the surface of Bi2Se3 film evolved from the worm-like structure to particles. The highly uniform thin film was formed on further increasing the plasma treatment time, which is consistent with the observed SEM results. Several important processes can result in the morphological evolution of Bi2Se3 nanosheets: (1) formation of Bi2Se3 oxide layer; (2) self-assembly of oxide nanoparticles under the action of high-energy oxygen plasma; and (3) electrostatic interaction and etching mechanism. PMID:26923325

  16. Morphological evolution of self-deposition Bi2Se3 nanosheets by oxygen plasma treatment

    NASA Astrophysics Data System (ADS)

    Jia, Guozhi; Wu, Zengna; Wang, Peng; Yao, Jianghong; Chang, Kai

    2016-02-01

    Bi2Se3 nanosheets were successfully synthesized by a microwave-assisted approach in the presence of polyvinylpyrroli done at a temperature of 180 °C for 2 h. The thin film was prepared on a silicon wafer via a self-deposition process in a Bi2Se3 nanosheet ink solution using the evaporation-induced self-assembly method. The structure and morphology of the obtained products were characterized by X-ray diffraction, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy, and Raman spectroscopy. The highly uniform Bi2Se3 particles could be formed by controlling the oxygen plasma treatment time. After the plasma pretreatment from 10 to 20 s, the surface of Bi2Se3 film evolved from the worm-like structure to particles. The highly uniform thin film was formed on further increasing the plasma treatment time, which is consistent with the observed SEM results. Several important processes can result in the morphological evolution of Bi2Se3 nanosheets: (1) formation of Bi2Se3 oxide layer; (2) self-assembly of oxide nanoparticles under the action of high-energy oxygen plasma; and (3) electrostatic interaction and etching mechanism.

  17. Plasma interactions determine the composition in pulsed laser deposited thin films

    SciTech Connect

    Chen, Jikun; Stender, Dieter; Conder, Kazimierz; Wokaun, Alexander; Schneider, Christof W.; Lippert, Thomas; Döbeli, Max

    2014-09-15

    Plasma chemistry and scattering strongly affect the congruent, elemental transfer during pulsed laser deposition of target metal species in an oxygen atmosphere. Studying the plasma properties of La{sub 0.6}Sr{sub 0.4}MnO{sub 3}, we demonstrate for as grown La{sub 0.6}Sr{sub 0.4}MnO{sub 3-δ} films that a congruent transfer of metallic species is achieved in two pressure windows: ∼10{sup −3} mbar and ∼2 × 10{sup −1} mbar. In the intermediate pressure range, La{sub 0.6}Sr{sub 0.4}MnO{sub 3-δ} becomes cation deficient and simultaneously almost fully stoichiometric in oxygen. Important for thin film growth is the presence of negative atomic oxygen and under which conditions positive metal-oxygen ions are created in the plasma. This insight into the plasma chemistry shows why the pressure window to obtain films with a desired composition and crystalline structure is narrow and requires a careful adjustment of the process parameters.

  18. Magnetically controlled deposition of metals using gas plasma. Quarterly progress report, January 1997--March 1997

    SciTech Connect

    1997-05-01

    Thin layers of secondary material are plated on substrates either by plating or spraying processes. Plating operations produce large amounts of hazardous liquid waste. Spraying, while one of the less waste intensive methods, produces {open_quotes}over spray,{close_quotes} or waste that is a result of uncontrolled nature of the spray stream. In many cases the over spray may produce a hazardous waste, requiring special processing. Spray coating is a mature process with many uses. Material can be deposited utilizing spraying technology in three basic ways: {open_quotes}Flame spraying{close_quotes}, direct spraying of molten metals and/or plasma spraying. This project is directed at controlling the plasma spraying process and thereby minimizing the waste generated in that process. The proposed process will utilize a standard plasma spray gun with the addition of magnetic fields to focus and control the plasma. In order to keep development cost at a minimum, the project was organized in phases. The first and current phase involves developing an analytical model that will prove the concept and be used to design a prototype. Analyzing the process and using the analysis has the potential to generate significant hardware cost savings.

  19. Performance comparison of plasma spray and physical vapor deposition BC23 coatings in the LM2500

    SciTech Connect

    Wortman, D.J.

    1985-11-01

    Operation of US Navy Component Improvement Program LM2500 engines on the GTS Callaghan has provided an at-sea test bed for evaluation of hot corrosion on gas turbine engine components. In a presentation at a previous International Conference on Metallurgical Coatings, (ICMC), comparison of several coatings applied by physical vapor deposition (PVD) techniques were compared after LM2500 service. A three-step coating BC23 consisting of PVD CoCrAl followed by codeposition of hafnium and aluminum and an electroplated platinum layer was identified as the most corrosion-resistant coating of several PVD coatings tested. In this paper, a plasma sprayed version of BC23 is compared to the three-step BC23 coating on LM2500 Stage 2 HPT blades from the GTS Callaghan. The plasma sprayed coating PBC23 was produced by an argon-shrouded plasma spray process using prealloyed CoCrAlHfPt powder. The results showed that in this application, where low temperature hot corrosion (type 2) is the predominant mode of corrosion, the plasma sprayed coatings had less attack. These results are compared to laboratory hot corrosion tests and microprobe analysis to explain the improved corrosion resistance of PBC23.

  20. Vapors and Droplets Mixture Deposition of Metallic Coatings by Very Low Pressure Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Vautherin, B.; Planche, M.-P.; Bolot, R.; Quet, A.; Bianchi, L.; Montavon, G.

    2014-04-01

    In recent years, the very low pressure plasma-spraying (VLPPS) process has been intensely developed and implemented to manufacture thin, dense and finely structured ceramic coatings for various applications, such as Y2O3 for diffusion barriers, among other examples. This paper aims at presenting developments carried out on metallic coatings. Aluminum was chosen as a demonstrative material due to its "moderate" vaporization enthalpy (i.e., 38.23 KJ cm-3) compared to the one of copper (i.e., 55.33 KJ cm-3), cobalt (i.e., 75.03 KJ cm-3), or even tantalum (i.e., 87.18 KJ cm-3). The objective of this work is primarily to better understand the behavior of a solid precursor injected into the plasma jet leading to the formation of vapors and to better control the factors affecting the coating structure. Nearly dense aluminum coatings were successfully deposited by VLPPS at 100 Pa with an intermediate power plasma torch (i.e., Sulzer Metco F4 type gun with maximum power of 45 kW). Optical emission spectroscopy (OES) was implemented to study and analyze the vapor behavior into the plasma jet. Simplified CFD modeling allowed better understanding of some of the thermo-physical mechanisms. The effect of powder-size distribution, substrate temperature and spray distance were studied. The phase composition and microstructural features of the coatings were characterized by XRD and SEM. Moreover, Vickers microhardness measurements were implemented.

  1. Morphological evolution of self-deposition Bi2Se3 nanosheets by oxygen plasma treatment.

    PubMed

    Jia, Guozhi; Wu, Zengna; Wang, Peng; Yao, Jianghong; Chang, Kai

    2016-01-01

    Bi2Se3 nanosheets were successfully synthesized by a microwave-assisted approach in the presence of polyvinylpyrroli done at a temperature of 180 °C for 2 h. The thin film was prepared on a silicon wafer via a self-deposition process in a Bi2Se3 nanosheet ink solution using the evaporation-induced self-assembly method. The structure and morphology of the obtained products were characterized by X-ray diffraction, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy, and Raman spectroscopy. The highly uniform Bi2Se3 particles could be formed by controlling the oxygen plasma treatment time. After the plasma pretreatment from 10 to 20 s, the surface of Bi2Se3 film evolved from the worm-like structure to particles. The highly uniform thin film was formed on further increasing the plasma treatment time, which is consistent with the observed SEM results. Several important processes can result in the morphological evolution of Bi2Se3 nanosheets: (1) formation of Bi2Se3 oxide layer; (2) self-assembly of oxide nanoparticles under the action of high-energy oxygen plasma; and (3) electrostatic interaction and etching mechanism. PMID:26923325

  2. Modeling of Sheath Ion-Molecule Reactions in Plasma Enhanced Chemical Vapor Deposition of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Hash, David B.; Govindan, T. R.; Meyyappan, M.

    2004-01-01

    In many plasma simulations, ion-molecule reactions are modeled using ion energy independent reaction rate coefficients that are taken from low temperature selected-ion flow tube experiments. Only exothermic or nearly thermoneutral reactions are considered. This is appropriate for plasma applications such as high-density plasma sources in which sheaths are collisionless and ion temperatures 111 the bulk p!asma do not deviate significantly from the gas temperature. However, for applications at high pressure and large sheath voltages, this assumption does not hold as the sheaths are collisional and ions gain significant energy in the sheaths from Joule heating. Ion temperatures and thus reaction rates vary significantly across the discharge, and endothermic reactions become important in the sheaths. One such application is plasma enhanced chemical vapor deposition of carbon nanotubes in which dc discharges are struck at pressures between 1-20 Torr with applied voltages in the range of 500-700 V. The present work investigates The importance of the inclusion of ion energy dependent ion-molecule reaction rates and the role of collision induced dissociation in generating radicals from the feedstock used in carbon nanotube growth.

  3. Deposition of nanostructured photocatalytic zinc ferrite films using solution precursor plasma spraying

    SciTech Connect

    Dom, Rekha; Sivakumar, G.; Hebalkar, Neha Y.; Joshi, Shrikant V.; Borse, Pramod H.

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Highly economic solution precursor route capable of producing films/coating even for mass scale production. Black-Right-Pointing-Pointer Pure spinel phase ZnFe{sub 2}O{sub 4} porous, immobilized films deposited in single step. Black-Right-Pointing-Pointer Parameter optimization yields access to nanostructuring in SPPS method. Black-Right-Pointing-Pointer The ecofriendly immobilized ferrite films were active under solar radiation. Black-Right-Pointing-Pointer Such magnetic system display advantage w.r.t. recyclability after photocatalyst extraction. -- Abstract: Deposition of pure spinel phase, photocatalytic zinc ferrite films on SS-304 substrates by solution precursor plasma spraying (SPPS) has been demonstrated for the first time. Deposition parameters such as precursor solution pH, concentration, film thickness, plasma power and gun-substrate distance were found to control physico-chemical properties of the film, with respect to their crystallinity, phase purity, and morphology. Alkaline precursor conditions (7 < pH {<=} 10) were found to favor oxide film formation. The nanostructured films produced under optimized conditions, with 500 mM solution at pH {approx} 8.0, yielded pure cubic phase ZnFe{sub 2}O{sub 4} film. Very high/low precursor concentrations yielded mixed phase, less adherent, and highly inhomogeneous thin films. Desired spinel phase was achieved in as-deposited condition under appropriately controlled spray conditions and exhibited a band gap of {approx}1.9 eV. The highly porous nature of the films favored its photocatalytic performance as indicated by methylene blue de-coloration under solar radiation. These immobilized films display good potential for visible light photocatalytic applications.

  4. Photocatalytic Functional Coating of TiO2 Thin Film Deposited by Cyclic Plasma Chemical Vapor Deposition at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Kwon, Jung-Dae; Rha, Jong-Joo; Nam, Kee-Seok; Park, Jin-Seong

    2011-08-01

    Photocatalytic TiO2 thin films were prepared with titanium tetraisopropoxide (TTIP) using cyclic plasma chemical vapor deposition (CPCVD) at atmospheric pressure. The CPCVD TiO2 films contain carbon-free impurities up to 100 °C and polycrystalline anatase phases up to 200 °C, due to the radicals and ion-bombardments. The CPCVD TiO2 films have high transparency in the visible wavelength region and absorb wavelengths below 400 nm (>3.2 eV). The photocatalytic effects of the CPCVD TiO2 and commercial sprayed TiO2 films were measured by decomposing methylene blue (MB) solution under UV irradiation. The smooth CPCVD TiO2 films showed a relatively lower photocatalytic efficiency, but superior catalyst-recycling efficiency, due to their high adhesion strength on the substrates. This CPCVD technique may provide the means to produce photocatalytic thin films with low cost and high efficiency, which would be a reasonable candidate for practical photocatalytic applications, because of the reliability and stability of their photocatalytic efficiency in a practical environment.

  5. Influence of atomic layer deposition valve temperature on ZrN plasma enhanced atomic layer deposition growth

    SciTech Connect

    Muneshwar, Triratna Cadien, Ken

    2015-11-15

    Atomic layer deposition (ALD) relies on a sequence of self-limiting surface reactions for thin film growth. The effect of non-ALD side reactions, from insufficient purging between pulses and from precursor self-decomposition, on film growth is well known. In this article, precursor condensation within an ALD valve is described, and the effect of the continuous precursor source from condensate evaporation on ALD growth is discussed. The influence of the ALD valve temperature on growth and electrical resistivity of ZrN plasma enhanced ALD (PEALD) films is reported. Increasing ALD valve temperature from 75 to 95 °C, with other process parameters being identical, decreased both the growth per cycle and electrical resistivity (ρ) of ZrN PEALD films from 0.10 to 0.07 nm/cycle and from 560 to 350 μΩ cm, respectively. Our results show that the non-ALD growth resulting from condensate accumulation is eliminated at valve temperatures close to the pressure corrected boiling point of precursor.

  6. Plasma enhanced chemical vapor deposition (PECVD) method of forming vanadium oxide films and vanadium oxide thin-films prepared thereby

    DOEpatents

    Zhang, Ji-Guang; Tracy, C. Edwin; Benson, David K.; Turner, John A.; Liu, Ping

    2000-01-01

    A method is disclosed of forming a vanadium oxide film on a substrate utilizing plasma enhanced chemical vapor deposition. The method includes positioning a substrate within a plasma reaction chamber and then forming a precursor gas comprised of a vanadium-containing chloride gas in an inert carrier gas. This precursor gas is then mixed with selected amounts of hydrogen and oxygen and directed into the reaction chamber. The amounts of precursor gas, oxygen and hydrogen are selected to optimize the final properties of the vanadium oxide film An rf plasma is generated within the reaction chamber to chemically react the precursor gas with the hydrogen and the oxygen to cause deposition of a vanadium oxide film on the substrate while the chamber deposition pressure is maintained at about one torr or less. Finally, the byproduct gases are removed from the plasma reaction chamber.

  7. Low-Temperature Silicon Epitaxy by Remote, Plasma - Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Habermehl, Scott Dwight

    The dynamics of low temperature Si homoepitaxial and heteroepitaxial growth, by remote plasma enhanced chemical vapor deposition, RPECVD, have been investigated. For the critical step of pre-deposition surface preparation of Si(100) surfaces, the attributes of remote plasma generated atomic H are compared to results obtained with a rapid thermal desorption, RTD, technique and a hybrid H-plasma/RTD technique. Auger electron spectroscopy, AES, and electron diffraction analysis indicate the hybrid technique to be very effective at surface passivation, while the RTD process promotes the formation of SiC precipitates, which induce defective epitaxial growth. For GaP and GaAs substrates, the use of atomic H exposure is investigated as a surface passivation technique. AES shows this technique to be effective at producing atomically clean surfaces. For processing at 400^circrm C, the GaAs(100) surface is observed to reconstruct to a c(8 x 2)Ga symmetry while, at 530^ circrm C the vicinal GaP(100) surface, miscut 10^circ , is observed to reconstruct to a (1 x n) type symmetry; an unreconstructed (1 x 1) symmetry is observed for GaP(111). Differences in the efficiency with which native oxides are removed from the surface are attributed to variations in the local atomic bonding order of group V oxides. The microstructure of homoepitaxial Si films, deposited at temperatures of 25-450^circ rm C and pressures of 50-500 mTorr, is catalogued. Optimized conditions for the deposition of low defect, single crystal films are identified. The existence of two pressure dependent regimes for process activation are observed. In-situ mass spectral analysis indicates that the plasma afterglow is dominated by monosilane ions below 200 mTorr, while above 200 mTorr, low mass rm H_{x} ^+ (x = 1,2,3) and rm HHe^+ ions dominate. Consideration of the growth rate data indicates that downstream dissociative silane ionization, in the lower pressure regime, is responsible for an enhanced surface H

  8. Ion bombardment-induced mechanical stress in plasma-enhanced deposited silicon nitride and silicon oxynitride films

    SciTech Connect

    Claassen, W.A.P.

    1987-03-01

    The authors have studied the influence of different deposition conditions on the mechanical stress of silicon nitride and silicon oxynitride layers formed by plasma-enhanced deposition onto silicon substrates. It appears that the mechanical stress of the as-deposited silicon (oxy)nitride layer is a combined effect of the extent of ion bombardment and the deposition temperature on the hydrogen desorption rate. Deposited films show a tensile stress character when the hydrogen desorption rate is thermally controlled, whereas in the case of an ion-bombardment-controlled hydrogen desorption rate the deposited films have a compressive stress. It is also shown that due to annealing at temperatures above the deposition temperature the films are densified as a result of hydrogen desorption and cross-linking.

  9. Single-chamber plasma enhanced chemical vapor deposition of transparent organic/inorganic multilayer barrier coating at low temperature

    SciTech Connect

    Park, S. M.; Kim, D. J.; Kim, S. I.; Lee, N.-E.

    2008-07-15

    Deposition of organic/inorganic multilayers is usually carried out by two different process steps by two different deposition methods. A single-chamber process for the deposition of multilayer stacks can make the process and deposition system simpler. In this work, SiOCH and plasma-polymerized methylcyclohexane (pp-MCH) films and their multilayer stacks for application to transparent diffusion barrier coatings were deposited in a single low-temperature plasma enhanced chemical vapor deposition reactor using hexamethyldisilazane/N{sub 2}O/O{sub 2}/Ar and methylcyclohexane/Ar mixtures for SiOCH and pp-MCH layers, respectively. The deposition rates of the SiOCH and pp-MCH layers were increased with increasing the N{sub 2}O:O{sub 2} gas flow ratio and rf plasma power, respectively. Oxygen concentration in the SiOCH films was decreased and carbon and hydrogen incorporation was increased when increasing the N{sub 2}O:O{sub 2} gas flow ratio from 0:1 to 3:1. In this work, the water vapor transmission rate of polyester sulfone substrate could be reduced from a level of 50 (bare substrate) to 0.8 g/m{sup 2} day after deposition of a pp-MCH/SiOCH/pp-MCH multilayer coating.

  10. Temperature dependence of the biaxial modulus, intrinsic stress and composition of plasma deposited silicon oxynitride films

    NASA Technical Reports Server (NTRS)

    Harding, David R.; Ogbuji, Linus U. T.; Freeman, Mathieu J.

    1995-01-01

    Silicon oxynitride films were deposited by plasma-enhanced chemical-vapor deposition. The elemental composition was varied between silicon nitride and silicon dioxide: SiO(0.3)N(1.0), SiO(0.7)N(1.6), SiO(0.7)N(1.1), and SiO(1.7)N(0.%). These films were annealed in air, at temperatures of 40-240 C above the deposition temperature (260 C), to determine the stability and behavior or each composition. the biaxial modulus, biaxial intrinsic stress, and elemental composition were measured at discrete intervals within the annealing cycle. Films deposited from primarily ammonia possessed considerable hydrogen (up to 38 at.%) and lost nitrogen and hydrogen at anneal temperatures (260-300 C) only marginally higher than the deposition temperature. As the initial oxygen content increased a different mechanism controlled the behavior or the film: The temperature threshold for change rose to approximately equal to 350 C and the loss of nitrogen was compensated by an equivalent rise in the oxygen content. The transformation from silicon oxynitride to silica was completed after 50 h at 400 C. The initial biaxial modulus of all compositions was 21-3- GPa and the intrinsic stress was -30 to 85 MPa. Increasing the oxygen content raised the temperature threshold where cracking first occurred; the two film compositions with the highest initial oxygen content did not crack, even at the highest temperature (450 C) investigated. At 450 C the biaxial modulus increased to approximately equal to 100 GPa and the intrinsic stress was approximately equal to 200 MPa. These increases could be correlated with the observed change in the film's composition. When nitrogen was replaced by oxygen, the induced stress remained lower than the biaxial strength of the material, but, when nitrogen and hydrogen were lost, stress-relieving microcracking occurred.

  11. High photoelectron emission from Co-diffused MgO deposited using arc plasma gun

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shin-ichi; Kosuga, Hiroki

    2015-08-01

    MgO has several advantageous characteristics and has been applied in various fields. In this study, we deposited Co nanoparticles in an island pattern on a Si substrate using an arc plasma gun (APG). We subsequently formed a MgO thin film on this substrate by metal-organic decomposition (MOD), which enables the formation of films in the atmosphere, thereby yielding a double-layer structure. The MgO thin film formed on Co nanoparticles deposited using the APG with 500 pulses of arc discharge exhibited improved crystallinity and photoelectron emission at least threefold higher than that of a MgO thin film formed directly without depositing Co nanoparticles. Although the transmittance of the specimen formed by depositing Co nanoparticles was initially 30% or lower, it increased to greater than 90% after the formation of the MgO thin film and the dispersion of the Co nanoparticles in the MgO thin film during heat treatment at 900 °C. Our results clarify that the characteristics of MgO thin films are markedly improved by depositing Co nanoparticles before forming the films. The results of Kelvin probe force microscopy (KPFM) indicate that the outermost surface of the Co material had become CoO (cobalt oxide) with the dispersion of Co nanoparticles in the MgO thin film. The lattice parameter of CoO nanoparticles (an-axis lattice parameter of 4.2615 Å) after heating matches well with that of MgO (4.2126 Å). The MgO thin films that grew in conjunction with the CoO nanoparticles were highly crystallized. We successfully established a high-performance, cost-effective bottom-up process that requires no ion injection by dispersing Co nanoparticles in a MgO thin film through heat treatment.

  12. In situ process diagnostics of silane plasma for device-quality a-Si:H deposition

    NASA Astrophysics Data System (ADS)

    Shing, Y. H.; Perry, J. W.; Hermann, A. M.

    Coherent anti-Stokes Raman spectroscopy (CARS) and mass spectrometry (MS) have been applied to in situ process diagnostics of a silane plasma for device-quality a-Si:H film deposition. Silane depletion was directly measured by CARS and is linearly dependent on RF power in the region of 4-12 W with a slope of 0.5 percent/mW-sq cm. The depletion is also dependent on SiH4 flow rate starting with a 50 percent depletion at a low flow rate of 5.6 sccm and asymptotically approaching an 8 percent depletion at a flow rate of 80 sccm. The mass spectral line signal intensity of disilane increases with RF power and shows an apparent transition at 6 W. Disilane formation in silane plasma, film deposition rate, and silane depletion ratio as a function of the RF power indicate that the film growth mechanism in the low-power region of 3.5-6.5 W is substantially different from that in the high-power region of 6.5-12 W.

  13. Preparation of cubic boron nitride thin film by the helicon wave plasma enhanced chemical vapor deposition

    SciTech Connect

    Kim, S.; Kim, I.; Kim, K.

    1996-12-01

    Cubic boron nitride ({ital c}-BN) film was deposited on Si(100) substrate using the chemical vapor deposition process assisted by high density plasma of Helicon wave with Borazine (B{sub 3}N{sub 3}H{sub 6}) precursor. It was found that the bombardment of ions with high flux and energy onto the film was necessarily required for synthesizing a {ital c}-BN film. Increasing a negative rf bias on the substrate increased the formation fraction of {ital c}-BN in the film. A nearly pure {ital c}-BN phase was synthesized at the conditions of plasma density in the reactor and rf substrate bias, above 10{sup 11} cm{sup {minus}3} and {minus}350 V, respectively. The phase identification of BN film was carried out by the transmission electron microscopy as well as Fourier transformed infrared spectroscopy. The infrared spectra for {ital c}-BN film synthesized at the rf bias of {minus}350 V appeared at 1093 cm{sup {minus}1} with a strong single peak, which is close to a value for the characteristic vibration mode of bulk {ital c}-BN (1065 cm{sup {minus}1}). The {ital c}-BN in the film was also confirmed and found to be a fine poly-crystalline with the grain sizes ranging from 200 to 400 A. {copyright} {ital 1996 American Institute of Physics.}

  14. A mathematical model and simulation results of plasma enhanced chemical vapor deposition of silicon nitride films

    NASA Astrophysics Data System (ADS)

    Konakov, S. A.; Krzhizhanovskaya, V. V.

    2015-01-01

    We developed a mathematical model of Plasma Enhanced Chemical Vapor Deposition (PECVD) of silicon nitride thin films from SiH4-NH3-N2-Ar mixture, an important application in modern materials science. Our multiphysics model describes gas dynamics, chemical physics, plasma physics and electrodynamics. The PECVD technology is inherently multiscale, from macroscale processes in the chemical reactor to atomic-scale surface chemistry. Our macroscale model is based on Navier-Stokes equations for a transient laminar flow of a compressible chemically reacting gas mixture, together with the mass transfer and energy balance equations, Poisson equation for electric potential, electrons and ions balance equations. The chemical kinetics model includes 24 species and 58 reactions: 37 in the gas phase and 21 on the surface. A deposition model consists of three stages: adsorption to the surface, diffusion along the surface and embedding of products into the substrate. A new model has been validated on experimental results obtained with the "Plasmalab System 100" reactor. We present the mathematical model and simulation results investigating the influence of flow rate and source gas proportion on silicon nitride film growth rate and chemical composition.

  15. In situ process diagnostics of silane plasma for device-quality a-Si:H deposition

    NASA Technical Reports Server (NTRS)

    Shing, Y. H.; Perry, J. W.; Hermann, A. M.

    1987-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) and mass spectrometry (MS) have been applied to in situ process diagnostics of a silane plasma for device-quality a-Si:H film deposition. Silane depletion was directly measured by CARS and is linearly dependent on RF power in the region of 4-12 W with a slope of 0.5 percent/mW-sq cm. The depletion is also dependent on SiH4 flow rate starting with a 50 percent depletion at a low flow rate of 5.6 sccm and asymptotically approaching an 8 percent depletion at a flow rate of 80 sccm. The mass spectral line signal intensity of disilane increases with RF power and shows an apparent transition at 6 W. Disilane formation in silane plasma, film deposition rate, and silane depletion ratio as a function of the RF power indicate that the film growth mechanism in the low-power region of 3.5-6.5 W is substantially different from that in the high-power region of 6.5-12 W.

  16. The effect of nitrogen incorporation in DLC films deposited by ECR Microwave Plasma CVD

    NASA Astrophysics Data System (ADS)

    Seker, Z.; Ozdamar, H.; Esen, M.; Esen, R.; Kavak, H.

    2014-09-01

    Diamond like carbon (DLC) and nitrogenated diamond like carbon (DLC:N) films have been deposited by electron cyclotron resonance microwave plasma chemical vapor deposition (ECR-MP CVD) on Si (1 1 0), steel and glass substrates, using CH4 and N2 as plasma source. The effect of nitrogen doping on the optical, electrical, structural and mechanical properties of films was investigated. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy results showed that sp2 bonded carbon phases increased while the sp3 bonded carbon phases decreased by nitrogen doping. Microhardness measurements showed a decrease in hardness (from 75 to 69 GPa) according to nitrogen incorporation. Average transmittance of all the films was over 90% and band gap energy (Eg) of the films decreased due to increasing nitrogen flow rate. The film morphology was studied using the atomic force microscopy (AFM). Electrical properties were characterized by Hall measurement. Undoped DLC was p-type with a conductivity of 9.81 × 10-6 (Ω cm)-1. DLC films became n-type by nitrogen doping. The best conductivity value for the nitrogen doped DLC films was found 2.77 × 10-5 (Ω cm)-1. PL spectra of DLC and DLC:N films showed three peaks at 405 nm (3.06 eV), 533 nm (2.32 eV) and 671 nm (1.84 eV).

  17. Development of dielectric barrier discharge plasma processing apparatus for mass spectrometry and thin film deposition

    SciTech Connect

    Majumdar, Abhijit; Hippler, Rainer

    2007-07-15

    Cost effective and a very simple dielectric barrier discharge plasma processing apparatus for thin film deposition and mass spectroscopic analysis of organic gas mixture has been described. The interesting features of the apparatus are the construction of the dielectric electrodes made of aluminum oxide or alumina (Al{sub 2}O{sub 3}) and glass and the generation of high ignition voltage from the spark plug transformer taken from car. Metal capacitor is introduced in between ground and oscilloscope to measure the executing power during the discharge and the average electron density in the plasma region. The organic polymer films have been deposited on Si (100) substrate using several organic gas compositions. The experimental setup provides a unique drainage system from the reaction chamber controlled by a membrane pump to suck out and remove the poisonous gases or residuals (cyanogens, H-CN, CH{sub x}NH{sub 2}, etc.) which have been produced during the discharge of CH{sub 4}/N{sub 2} mixture.

  18. Plasma Processing of Functional Thin Films by Sputtering Deposition Using Metal-Based Powder Target

    NASA Astrophysics Data System (ADS)

    Kawasaki, Hiroharu; Ohshima, Tamiko; Ihara, Takeshi; Arafune, Kento; Taniyama, Daichi; Yagyu, Yoshihito; Suda, Yoshiaki

    2013-11-01

    Titanium-based functional thin films were prepared by a sputtering deposition method using a metal powder target, and the electron density and temperature of the processing plasma were investigated. The electron density of the plasma, measured by a probe method, when using a powder target was higher than that when using a bulk target. The deposition rate when using a powder target was also higher than that in the case of a bulk target. These results may be due to the net-cathode area of the powder target being larger than that of the bulk target. X-ray photoelectron spectroscopy, X-ray diffraction measurements, and atomic force microscopy images of the films prepared using the Ti powder target indicated nearly the same properties as those of films prepared using a Ti bulk target, and the prepared films are oxide. These results suggest that TiO2 thin films can be prepared using a Ti powder target and that the quality is almost the same as those of films prepared using a Ti bulk target.

  19. A simple method to deposit palladium doped SnO{sub 2} thin films using plasma enhanced chemical vapor deposition technique

    SciTech Connect

    Kim, Young Soon; Wahab, Rizwan; Shin, Hyung-Shik; Ansari, S. G.; Ansari, Z. A.

    2010-11-15

    This work presents a simple method to deposit palladium doped tin oxide (SnO{sub 2}) thin films using modified plasma enhanced chemical vapor deposition as a function of deposition temperature at a radio frequency plasma power of 150 W. Stannic chloride (SnCl{sub 4}) was used as precursor and oxygen (O{sub 2}, 100 SCCM) (SCCM denotes cubic centimeter per minute at STP) as reactant gas. Palladium hexafluroacetyleacetonate (Pd(C{sub 5}HF{sub 6}O{sub 2}){sub 2}) was used as a precursor for palladium. Fine granular morphology was observed with tetragonal rutile structure. A peak related to Pd{sub 2}Sn is observed, whose intensity increases slightly with deposition temperature. Electrical resistivity value decreased from 8.6 to 0.9 m{Omega} cm as a function of deposition temperature from 400 to 600 deg. C. Photoelectron peaks related to Sn 3d, Sn 3p3, Sn 4d, O 1s, and C 1s were detected with varying intensities as a function of deposition temperature.

  20. Effect of hydrogen addition on the deposition of titanium nitride thin films in nitrogen added argon magnetron plasma

    NASA Astrophysics Data System (ADS)

    Saikia, P.; Bhuyan, H.; Diaz-Droguett, D. E.; Guzman, F.; Mändl, S.; Saikia, B. K.; Favre, M.; Maze, J. R.; Wyndham, E.

    2016-06-01

    The properties and performance of thin films deposited by plasma assisted processes are closely related to their manufacturing techniques and processes. The objective of the current study is to investigate the modification of plasma parameters occurring during hydrogen addition in N2  +  Ar magnetron plasma used for titanium nitride thin film deposition, and to correlate the measured properties of the deposited thin film with the bulk plasma parameters of the magnetron discharge. From the Langmuir probe measurements, it was observed that the addition of hydrogen led to a decrease of electron density from 8.6 to 6.2  ×  (1014 m‑3) and a corresponding increase of electron temperature from 6.30 to 6.74 eV. The optical emission spectroscopy study reveals that with addition of hydrogen, the density of argon ions decreases. The various positive ion species involving hydrogen are found to increase with increase of hydrogen partial pressure in the chamber. The thin films deposited were characterized using standard surface diagnostic tools such as x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), x-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Although it was possible to deposit thin films of titanium nitride with hydrogen addition in nitrogen added argon magnetron plasma, the quality of the thin films deteriorates with higher hydrogen partial pressures.

  1. Organo-Chlorinated Thin Films Deposited by Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition for Adhesion Enhancement between Rubber and Zinc-Plated Steel Monofilaments.

    PubMed

    Vandenabeele, Cédric; Bulou, Simon; Maurau, Rémy; Siffer, Frederic; Belmonte, Thierry; Choquet, Patrick

    2015-07-01

    A continuous-flow plasma process working at atmospheric pressure is developed to enhance the adhesion between a rubber compound and a zinc-plated steel monofilament, with the long-term objective to find a potential alternative to the electrolytic brass plating process, which is currently used in tire industry. For this purpose, a highly efficient tubular dielectric barrier discharge reactor is built to allow the continuous treatment of "endless" cylindrical substrates. The best treatment conditions found regarding adhesion are Ar/O2 plasma pretreatment, followed by the deposition from dichloromethane of a 75 nm-thick organo-chlorinated plasma polymerized thin film. Ar/O2 pretreatment allows the removal of organic residues, coming from drawing lubricants, and induces external growth of zinc oxide. The plasma layer has to be preferably deposited at low power to conserve sufficient hydrocarbon moieties. Surface analyses reveal the complex chemical mechanism behind the establishment of strong adhesion levels, more than five times higher after the plasma treatment. During the vulcanization step, superficial ZnO reacts with the chlorinated species of the thin film and is converted into porous and granular bump-shaped ZnwOxHyClz nanostructures. Together, rubber additives diffuse through the plasma layer and lead to the formation of zinc sulfide on the substrate surface. Hence, two distinct interfaces, rubber/thin film and thin film/substrate, are established. On the basis of these observations, hypotheses explaining the high bonding strength results are formulated. PMID:26069994

  2. Characterization and protein-adsorption behavior of deposited organic thin film onto titanium by plasma polymerization with hexamethyldisiloxane.

    PubMed

    Hayakawa, Tohru; Yoshinari, Masao; Nemoto, Kimiya

    2004-01-01

    Plasma polymerized hexamethyldisiloxane (HMDSO) thin film was deposited onto titanium using a radio-frequency apparatus for the surface modification of titanium. A titanium disk was first polished using colloidal silica at pH=9.8. Plasma-polymerized HMDSO films were firmly attached to the titanium by heating the titanium to a temperature of approximately 250 degrees C. The thickness of the deposited film was 0.07-0.35mum after 10-60min of plasma polymerization. The contact angle with respect to double distilled water significantly increased after HMDSO coating. X-ray photoelectron spectroscopy revealed that the deposited thin film consisted of Si, C, and O atoms. No Ti peaks were observed on the deposited surface. The deposited HMDSO film was stable during 2-weeks immersion in phosphate buffer saline solution. Fourier transform reflection-absorption spectroscopy showed the formation of Si-H, Si-C, C-H, and Cz.dbnd6;O bonds in addition to Si-O-Si bonds. Quartz crystal microbalance-dissipation measurement demonstrated that the deposition of HMDSO thin films on titanium has a benefit for fibronectin adsorption at the early stage. In conclusion, plasma polymerization is a promising technique for the surface modification of titanium. HMDSO-coated titanium has potential application as a dental implant material. PMID:14580915

  3. Attempt of Deposition of Ag-Doped Amorphous Carbon Film by Ag-Cathode DC Plasma with CH4 Flow.

    PubMed

    Tsubota, Toshiki; Kuratsu, Kazuhiro; Murakami, Naoya; Ohno, Teruhisa

    2015-06-01

    A simple DC plasma apparatus having large Ag cathode with CH4 flow was used for the attempt to prepare Ag-doped amorphous carbon film. As the gaseous source, CH4 and the additive (N2 or Ar) were used for the plasma process. When N2 was the additive, the substrate surfaces after the plasma process were electrical conductor although high electrical resistance. The growth rate of the deposits decreased with increasing the amount of N2, and the deposits contained nitrogen. Although the small amount of silver was detected by XPS, the peak for Ag may not be in the carbon deposit but be in interlayer formed at Ar etching process. When Ar was the additive, the substrate surfaces after the plasma process were also electrical conductor although high electrical resistance. The growth rate of the deposits was almost independent of the amount of Ar, and the deposits contained no argon. The small XPS peaks for Ag may not be in the carbon deposit but be in interlayer formed at Ar etching process. Both the prepared samples had high antibiotic property. The method of this study could be used for the surface reforming with amorphous carbon coating having electrical conductivity and antibiotic property. PMID:26369089

  4. [ital In] [ital situ] infrared measurements of film and gas properties during the plasma deposition of amorphous hydrogenated silicon

    SciTech Connect

    Morrison, P.W. Jr.; Haigis, J.R. )

    1993-05-01

    This research has performed preliminary [ital in] [ital situ] Fourier transform infrared (FTIR) measurements during the plasma deposition of amorphous silicon ([ital a]-Si:H). Experiments demonstrate both gas phase and film measurements within a simple SiH[sub 4] plasma reactor using a specially modified FTIR spectrometer. Films are deposited on substrates of either gold (mirror finish) or stainless steel (matte finish). In particular, [ital in] [ital situ] emission/reflection FTIR of the film yields information about surface temperature, film thickness, and film composition. We have measured surface temperature to [plus minus]5 K and detected the onset of poor film growth at a thickness of 500--1000 A using the 2080 cm[sup [minus]1] absorption feature. A simple model for the reflectance of a film on a metal is employed to determine the thickness of the films. [ital In] [ital situ] emission/transmission FTIR of the plasma determines the gas composition and average gas temperature. Measurements show that the silane conversion is [similar to]11% within the plasma region for a typical deposition at 250 [degree]C and roughly doubles for a deposition at room temperature. The FTIR spectra show that most of this converted silane reappears as disilane (Si[sub 2]H[sub 6]). Before starting the plasma, the silane gas is [similar to]30 K cooler than the nominal substrate temperature of 250 [degree]C; starting the plasma raises the average temperature another 20 [degree]C.

  5. Characterization of Plasma Jet in Plasma Spray-Physical Vapor Deposition of YSZ Using a <80 kW Shrouded Torch Based on Optical Emission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Qing-Yu; Peng, Xiao-Zhuang; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu

    2015-08-01

    During plasma spray-physical vapor deposition (PS-PVD) of yttria-stabilized zirconia (YSZ) coatings, evaporation of the YSZ powder is essential, but quite difficult when using a commercial <80 kW plasma torch. In this study, a shrouded plasma torch was examined to improve the YSZ evaporation. The plasma characteristics were diagnosed using optical emission spectroscopy. Results showed that the electron number density in the plasma jet was maintained at an order of magnitude of 1014 cm-3, indicating local thermal equilibrium of the plasma jet. Compared with a conventional torch, the shrouded torch resulted in much higher plasma temperature and much lower electron number density. With the shrouded torch, more energy of the plasma was transferred to the YSZ material, leading to more evaporation of the YSZ powder and thereby a much higher deposition rate of the YSZ coating. These results show that use of a shrouded torch is a simple and effective approach to improve the evaporation of feedstock material during PS-PVD.

  6. Formation of Nanopore-Arrays by Plasma-based Thin FilmDeposition

    SciTech Connect

    Ji, Qing; Chen, Y.; Jiang, Ximan; Ji, Lili; Leung, K.N.

    2005-03-18

    The ability to fabricate membranes with arrays of apertures only a few nanometers in diameter are important to many fields of research, including ion beam lithography, DNA sequencing, single ion implantations, and single molecule studies. Because even the state-of-the-art lithography tools are limited in their ability to produce nanoscale features, alternative methods of fabricating single pores of nanometer scale have been developed, using ion-beam sculpting and focused-ion-beam assisted deposition. However, these methods cannot simultaneously produce multiple holes of nanometer dimension. Here we report a means of forming arrays of nanopores simultaneously on a thin, solid-state membrane using plasma-based thin-film deposition. By depositing layers of metallic thin films, the aperture sizes of pores in a pre-fabricated membrane can be reduced from a couple of micrometers down to tens of nanometers and even smaller. The technique offers a way to reduce the sizes of aperture of any shape in a variety of substrate materials, both conducting and insulating. Such arrays of nanopores can serve as membrane channels for DNA sequencing, as masks in ion-beam imprinters, for the fabrication of quantum dots, and in other applications.

  7. Functional metal oxide coatings by molecule-based thermal and plasma chemical vapor deposition techniques.

    PubMed

    Mathur, S; Ruegamer, T; Donia, N; Shen, H

    2008-05-01

    Deposition of thin films through vaccum processes plays an important role in industrial processing of decorative and functional coatings. Many metal oxides have been prepared as thin films using different techniques, however obtaining compositionally uniform phases with a control over grain size and distribution remains an enduring challenge. The difficulties are largely related to complex compositions of functional oxide materials, which makes a control over kinetics of nucleation and growth processes rather difficult to control thus resulting in non-uniform material and inhomogeneous grain size distribution. Application of tailor-made molecular precursors in low pressure or plasma-enhanced chemical vapor deposition (CVD) techniques offers a viable solution for overcoming thermodynamic impediments involved in thin film growth. In this paper molecule-based CVD of functional coatings is demonstrated for iron oxide (Fe2O3, Fe3O4), vanadium oxide (V2O5, VO2) and hafnium oxide (HfO2) phases followed by the characterization of their microstructural, compositional and functional properties which support the advantages of chemical design in simplifying deposition processes and optimizing functional behavior. PMID:18572690

  8. Wettability of modified silica layers deposited on glass support activated by plasma

    NASA Astrophysics Data System (ADS)

    Terpiłowski, Konrad; Rymuszka, Diana; Goncharuk, Olena V.; Sulym, Iryna Ya.; Gun'ko, Vladimir M.

    2015-10-01

    Fumed silica modified by hexamethyldisilazane [HDMS] and polydimethylsiloxane [PDMS] was dispersed in a polystyrene/chloroform solution. To increase adhesion between deposited silica layers and a glass surface, the latter was pretreated with air plasma for 30 s. The silica/polystyrene dispersion was deposited on the glass support using a spin coater. After deposition, the plates were dried in a desiccator for 24 h. Water advancing and receding contact angles were measured using the tilted plate method. The apparent surface free energy (γS) was evaluated using the contact angle hysteresis approach. The surface topography was determined using the optical profilometry method. Contact angles changed from 59.7° ± 4.4 (at surface coverage with trimethylsilyl groups Θ = 0.14) to 155° ± 3.1 at Θ = 1. The value of γS decreased from 51.3 ± 2.8 mJ/m2 (for the sample at the lowest value of Θ) to 1.0 ± 0.4 mJ/m2 for the most hydrophobic sample. Thus, some systems with a high degree of modification by HDMS showed superhydrophobicity, and the sliding angle amounted to about 16° ± 2.1.

  9. The Formation of Nanocrystalline Diamond Coating on WC Deposited by Microwave Assisted Plasma CVD

    NASA Astrophysics Data System (ADS)

    Toff, M. R. M.; Hamzah, E.; Purniawan, A.

    2010-03-01

    Diamond is one form of carbon structure. The extreme hardness and high chemical resistant of diamond coatings determined that many works on this area relate to coated materials for tribological applications in biomedicine, as mechanical seals or cutting tools for hard machining operations. In the work, nanocrystalline diamond (NCD) coated tungsten carbide (WC) have been deposited by microwave assisted plasma chemical vapor deposition (MAPCVD) from CH4/H2 mixtures. Morphology of NCD was investigated by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The quality of NCD is defined as ratio between diamond and non diamond and also full width at half maximum (FWHM) was determined using Raman spectra. The result found that the NCD structure can be deposited on WC surface using CH4/H2 gas mixture with grain size ˜20 nm to 100 nm. Increase %CH4 concentration due to increase the nucleation of NCD whereas decrease the quality of diamond. Based on Raman spectra, the quality of NCD is in the range ˜98.82-99.01% and 99.56-99.75% for NCD and microcrystalline (MCD), respectively. In addition, FWHM of NCD is high than MCD in the range of 8.664-62.24 cm-1 and 4.24-5.05 cm-1 for NCD and MCD respectively that indicate the crystallineity of NCD is smaller than MCD.

  10. Current transport mechanisms in plasma-enhanced atomic layer deposited AlN thin films

    SciTech Connect

    Altuntas, Halit E-mail: biyikli@unam.bilkent.edu.tr; Ozgit-Akgun, Cagla; Donmez, Inci; Biyikli, Necmi E-mail: biyikli@unam.bilkent.edu.tr

    2015-04-21

    Here, we report on the current transport mechanisms in AlN thin films deposited at a low temperature (i.e., 200 °C) on p-type Si substrates by plasma-enhanced atomic layer deposition. Structural characterization of the deposited AlN was carried out using grazing-incidence X-ray diffraction, revealing polycrystalline films with a wurtzite (hexagonal) structure. Al/AlN/ p-Si metal-insulator-semiconductor (MIS) capacitor structures were fabricated and investigated under negative bias by performing current-voltage measurements. As a function of the applied electric field, different types of current transport mechanisms were observed; i.e., ohmic conduction (15.2–21.5 MV/m), Schottky emission (23.6–39.5 MV/m), Frenkel-Poole emission (63.8–211.8 MV/m), trap-assisted tunneling (226–280 MV/m), and Fowler-Nordheim tunneling (290–447 MV/m). Electrical properties of the insulating AlN layer and the fabricated Al/AlN/p-Si MIS capacitor structure such as dielectric constant, flat-band voltage, effective charge density, and threshold voltage were also determined from the capacitance-voltage measurements.

  11. Surface modification of silicon-containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Jin, Yoonyoung; Desta, Yohannes; Goettert, Jost; Lee, G. S.; Ajmera, P. K.

    2005-07-01

    Surface modification of silicon-containing fluorocarbon (SiCF) films achieved by wet chemical treatments and through x-ray irradiation is examined. The SiCF films were prepared by plasma-enhanced chemical vapor deposition, using gas precursors of tetrafluoromethane and disilane. As-deposited SiCF film composition was analyzed by x-ray photoelectron spectroscopy. Surface modification of SiCF films utilizing n-lithiodiaminoethane wet chemical treatment is discussed. Sessile water-drop contact angle changed from 95°+/-2° before treatment to 32°+/-2° after treatment, indicating a change in the film surface characteristics from hydrophobic to hydrophilic. For x-ray irradiation on the SiCF film with a dose of 27.4 kJ/cm3, the contact angle of the sessile water drop changed from 95°+/-2° before radiation to 39°+/-3° after x-ray exposure. The effect of x-ray exposure on chemical bond structure of SiCF films is studied using Fourier transform infrared measurements. Electroless Cu deposition was performed to test the applicability of the surface modified films. The x-ray irradiation method offers a unique advantage in making possible surface modification in a localized area of high-aspect-ratio microstructures. Fabrication of a Ti-membrane x-ray mask is introduced here for selective surface modification using x-ray irradiation.

  12. Nanoindentation of plasma-deposited nitrogen-rich silicon nitride thin films

    NASA Astrophysics Data System (ADS)

    Soh, Martin T. K.; Fischer-Cripps, A. C.; Savvides, N.; Musca, C. A.; Faraone, L.

    2006-07-01

    Nanoindentation was performed on plasma-deposited nitrogen-rich silicon nitride thin films deposited on various substrates between 150 and 300°C. A very simple and effective depth-profiling method is introduced, which involves indentation of thin films deposited on substrates with different mechanical properties. The primary advantage of this method is that it avoids the complications associated with many of the complex mathematical models available to deconvolve thin film mechanical properties, while nevertheless allowing the user to visually identify thin film properties. This method is demonstrated on our thin films, which have a hardness between 14 and 21GPa, and reduced modulus between 120 and 160GPa. The initial rise in hardness at low contact depths, commonly attributed to an indentation-size effect, is shown to be due to elastic contact between the indenter and thin film surface. This demonstrates the perils of blindly following the 10% rule for hardness calculation. The contribution of elastic and plastic deformations from nanoindentation is used to clarify the physical meaning of hardness and reduced modulus.

  13. Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

    DOE PAGESBeta

    Demaurex, Bénédicte; Bartlome, Richard; Seif, Johannes P.; Geissbühler, Jonas; Alexander, Duncan T. L.; Jeangros, Quentin; Ballif, Christophe; De Wolf, Stefaan

    2014-08-05

    Low-temperature (≤ 180 °C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-ehanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems notmore » only from the growth conditions but also from unintentional contamination of the reactor. As a result of our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.« less

  14. Vacuum arc plasma generation and thin film deposition from a TiB2 cathode

    NASA Astrophysics Data System (ADS)

    Zhirkov, Igor; Petruhins, Andrejs; Naslund, Lars-Ake; Kolozsvári, Szilard; Polcik, Peter; Rosen, Johanna

    2015-11-01

    We have studied the utilization of TiB2 cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of metal borides.

  15. Failure of physical vapor deposition/plasma-sprayed thermal barrier coatings during thermal cycling

    NASA Astrophysics Data System (ADS)

    Teixeira, V.; Andritschky, M.; Gruhn, H.; Malléner, W.; Buchkremer, H. P.; Stöver, D.

    2000-06-01

    ZrO2-7 wt.% Y2O3 plasma-sprayed (PS) coatings were applied on high-temperature Ni-based alloys precoated by physical vapor deposition with a thin, dense, stabilized zirconia coating (PVD bond coat). The PS coatings were applied by atmospheric plasma spraying (APS) and inert gas plasma spraying (IPS) at 2 bar for different substrate temperatures. The thermal barrier coatings (TBCs) were tested by furnace isothermal cycling and flame thermal cycling at maximum temperatures between 1000 and 1150 °C. The temperature gradients within the duplex PVD/PS thermal barrier coatings during the thermal cycling process were modeled using an unsteady heat transfer program. This modeling enables calculation of the transient thermal strains and stresses, which contributes to a better understanding of the failure mechanisms of the TBC during thermal cycling. The adherence and failure modes of these coating systems were experimentally studied during the high-temperature testing. The TBC failure mechanism during thermal cycling is discussed in light of coating transient stresses and substrate oxidation.

  16. Vacuum arc plasma generation and thin film deposition from a TiB{sub 2} cathode

    SciTech Connect

    Zhirkov, Igor Petruhins, Andrejs; Naslund, Lars-Ake; Rosen, Johanna; Kolozsvári, Szilard; Polcik, Peter

    2015-11-02

    We have studied the utilization of TiB{sub 2} cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of metal borides.

  17. Supported plasma sputtering apparatus for high deposition rate over large area

    DOEpatents

    Moss, Ronald W.; McClanahan, Jr., Edwin D.; Laegreid, Nils

    1977-01-01

    A supported plasma sputtering apparatus is described having shaped electrical fields in the electron discharge region between the cathode and anode and the sputter region between the target and substrate while such regions are free of any externally applied magnetic field to provide a high deposition rate which is substantially uniform over a wide area. Plasma shaping electrodes separate from the anode and target shape the electrical fields in the electron discharge region and the sputter region to provide a high density plasma. The anode surrounds the target to cause substantially uniform sputtering over a large target area. In one embodiment the anode is in the form of an annular ring surrounding a flat target surface, such anode being provided with a ribbed upper surface which shields portions of the anode from exposure to sputtered material to maintain the electron discharge for a long stable operation. Several other embodiments accomplish the same result by using different anodes which either shield the anode from sputtered material, remove the sputtered coating on the anode by heating, or simultaneously mix sputtered metal from the auxiliary target with sputtered insulator from the main target so the resultant coating is conductive. A radio frequency potential alone or together with a D.C. potential, may be applied to the target for a greater sputtering rate.

  18. Plasma restructuring of catalysts for chemical vapor deposition of carbon nanotubes

    SciTech Connect

    Cantoro, M.; Hofmann, S.; Pisana, S.; Parvez, A.; Fasoli, A.; Scardaci, V.; Ferrari, A. C.; Robertson, J.; Mattevi, C.; Ducati, C.

    2009-03-15

    The growth of multiwalled carbon nanotubes and carbon nanofibers by catalytic chemical vapor deposition at lower temperatures is found to be aided by a separate catalyst pretreatment step in which the catalyst thin film is restructured into a series of nanoparticles with a more active surface. The restructuring is particularly effective when carried out by an ammonia plasma. The nature of the restructuring is studied by atomic force microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and Raman. We find that as the growth temperature decreases, there is a limiting maximum catalyst thickness, which gives any nanotube growth. Plasmas are found to restructure the catalyst by a combination of physical etching and chemical modification. Large plasma powers can lead to complete etching of thin catalyst films, and hence loss of activity. Ni is found to be the better catalyst at low temperatures because it easily reduced from any oxide form to the catalytically active metallic state. On the other hand, Fe gives the largest nanotube length and density yield at moderate temperatures because it is less easy to reduce at low temperatures and it is more easily poisoned at high temperatures.

  19. Silicon oxide barrier films deposited on PET foils in pulsed plasmas: influence of substrate bias on deposition process and film properties

    NASA Astrophysics Data System (ADS)

    Steves, S.; Ozkaya, B.; Liu, C.-N.; Ozcan, O.; Bibinov, N.; Grundmeier, G.; Awakowicz, P.

    2013-02-01

    A widely used plastic for packaging, polyethylene terephtalate (PET) offers limited barrier properties against gas permeation. For many applications of PET (from food packaging to micro electronics) improved barrier properties are essential. A silicon oxide barrier coating of PET foils is applied by means of a pulsed microwave driven low-pressure plasma. While the adjustment of the microwave power allows for a control of the ion production during the plasma pulse, a substrate bias controls the energy of ions impinging on the substrate. Detailed analysis of deposited films applying oxygen permeation measurements, x-ray photoelectron spectroscopy and atomic force microscopy are correlated with results from plasma diagnostics describing the deposition process. The influence of a change in process parameters such as gas mixture and substrate bias on the gas temperature, electron density, mean electron energy, ion energy and the atomic oxygen density is studied. An additional substrate bias results in an increase in atomic oxygen density up to a factor of 6, although plasma parameter such as electron density of ne = 3.8 ± 0.8 × 1017 m-3 and electron temperature of kBTe = 1.7 ± 0.1 eV are unmodified. It is shown that atomic oxygen densities measured during deposition process higher than nO = 1.8 × 1021 m-3 yield in barrier films with a barrier improvement factor up to 150. Good barrier films are highly cross-linked and show a smooth morphology.

  20. The deposition of chromium by the use of an inductively-coupled radio-frequency plasma torch

    SciTech Connect

    Carson, L.; Chumbley, L.S.

    1997-11-15

    This paper discusses attempts to deposit a layer of hard Cr metal, with properties similar to those of layers currently obtained by electrolytic methods, onto a metallic substrate using an inductively-coupled, radio-frequency plasma torch (ICP-RF) torch. Preliminary studies indicated that it might be possible to produce a suitable layer using a number of chromium-based compounds. For this study, Cr powders and a chromium precursor were injected into the high temperature region of the plasma plume, where thermal decomposition of the feed material produced Cr atoms that deposited onto the surface of metal substrates placed below the plasma torch. The films produced were examined to determine thickness, chemical compositions, and adherence. Since the goal of the project was to develop a coating method that was not only industrially suitable but also environmentally safe, care was taken to monitor the emissions produced by the system during deposition.

  1. Plasma-enhanced chemical vapor deposited silicon carbide as an implantable dielectric coating.

    PubMed

    Cogan, Stuart F; Edell, David J; Guzelian, Andrew A; Ping Liu, Ying; Edell, Robyn

    2003-12-01

    Amorphous silicon carbide (a-SiC) films, deposited by plasma-enhanced chemical vapor deposition (PECVD), have been evaluated as insulating coatings for implantable microelectrodes. The a-SiC was deposited on platinum or iridium wire for measurement of electrical leakage through the coating in phosphate-buffered saline (PBS, pH 7.4). Low leakage currents of <10(-11) A were observed over a +/-5-V bias. The electronic resistivity of a-SiC was 3 x 10(13) Omega-cm. Dissolution rates of a-SiC in PBS at 37 and 90 degrees C were determined from changes in infrared absorption band intensities and compared with those of silicon nitride formed by low-pressure chemical vapor deposition (LPCVD). Dissolution rates of LPCVD silicon nitride were 2 nm/h and 0.4 nm/day at 90 and 37 degrees C, respectively, while a-SiC had a dissolution rate of 0.1 nm/h at 90 degrees C and no measurable dissolution at 37 degrees C. Biocompatibility was assessed by implanting a-SiC-coated quartz discs in the subcutaneous space of the New Zealand White rabbit. Histological evaluation showed no chronic inflammatory response and capsule thickness was comparable to silicone or uncoated quartz controls. Amorphous SiC-coated microelectrodes were implanted in the parietal cortex for periods up to 150 days and the cortical response evaluated by histological evaluation of neuronal viability at the implant site. The a-SiC was more stable in physiological saline than LPCVD Si(3)N(4) and well tolerated in the cortex. PMID:14613234

  2. Solution precursor plasma deposition of nanostructured CdS thin films

    SciTech Connect

    Tummala, Raghavender; Guduru, Ramesh K.; Mohanty, Pravansu S.

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Inexpensive process with capability to produce large scale nanostructured coatings. Black-Right-Pointing-Pointer Technique can be employed to spray the coatings on any kind of substrates including polymers. Black-Right-Pointing-Pointer The CdS coatings developed have good electrical conductivity and optical properties. Black-Right-Pointing-Pointer Coatings possess large amount of particulate boundaries and nanostructured grains. -- Abstract: Cadmium sulfide (CdS) films are used in solar cells, sensors and microelectronics. A variety of techniques, such as vapor based techniques, wet chemical methods and spray pyrolysis are frequently employed to develop adherent CdS films. In the present study, rapid deposition of CdS thin films via plasma spray route using a solution precursor was investigated, for the first time. Solution precursor comprising cadmium chloride, thiourea and distilled water was fed into a DC plasma jet via an axial atomizer to create ultrafine droplets for instantaneous and accelerated thermal decomposition in the plasma plume. The resulting molten/semi-molten ultrafine/nanoparticles of CdS eventually propel toward the substrate to form continuous CdS films. The chemistry of the solution precursor was found to be critical in plasma pyrolysis to control the stoichiometry and composition of the films. X-ray diffraction studies confirmed hexagonal {alpha}-CdS structure. Surface morphology and microstructures were investigated to compare with other synthesis techniques in terms of process mechanism and structural features. Transmission electron microscopy studies revealed nanostructures in the atomized particulates. Optical measurements indicated a decreasing transmittance in the visible light with increasing the film thickness and band gap was calculated to be {approx}2.5 eV. The electrical resistivity of the films (0.243 {+-} 0.188 Multiplication-Sign 10{sup 5} {Omega} cm) was comparable with the literature

  3. Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor depositiona)

    NASA Astrophysics Data System (ADS)

    Bartlome, Richard; De Wolf, Stefaan; Demaurex, Bénédicte; Ballif, Christophe; Amanatides, Eleftherios; Mataras, Dimitrios

    2015-05-01

    We clarify the difference between the SiH4 consumption efficiency η and the SiH4 depletion fraction D, as measured in the pumping line and the actual reactor of an industrial plasma-enhanced chemical vapor deposition system. In the absence of significant polysilane and powder formation, η is proportional to the film growth rate. Above a certain powder formation threshold, any additional amount of SiH4 consumed translates into increased powder formation rather than into a faster growing Si film. In order to discuss a zero-dimensional analytical model and a two-dimensional numerical model, we measure η as a function of the radio frequency (RF) power density coupled into the plasma, the total gas flow rate, the input SiH4 concentration, and the reactor pressure. The adjunction of a small trimethylboron flow rate increases η and reduces the formation of powder, while the adjunction of a small disilane flow rate decreases η and favors the formation of powder. Unlike η, D is a location-dependent quantity. It is related to the SiH4 concentration in the plasma cp, and to the phase of the growing Si film, whether the substrate is glass or a c-Si wafer. In order to investigate transient effects due to the RF matching, the precoating of reactor walls, or the introduction of a purifier in the gas line, we measure the gas residence time and acquire time-resolved SiH4 density measurements throughout the ignition and the termination of a plasma.

  4. Very high frequency plasma deposited amorphous/nanocrystalline silicon tandem solar cells on flexible substrates

    NASA Astrophysics Data System (ADS)

    Liu, Y.

    2010-02-01

    The work in this thesis is to develop high quality intrinsic layers (especially nc-Si:H) for micromorph silicon tandem solar cells/modules on plastic substrates following the substrate transfer method or knows as the Helianthos procedure. Two objectives are covered in this thesis: (1) preliminary work on trial and optimization of single junction and tandem cells on glass substrate, (2) silicon film depositions on Al foil, and afterwards the characterization and development of these cells/modules on a plastic substrate. The first objective includes the development of suitable ZnO:Al TCO for nc Si:H single junction solar cells, fabrication of the aimed micromorph tandem solar cells on glass, and finally the optimization of the nc-Si:H i-layer for the depositions afterwards on Al foil. Chapter 3 addresses the improvement of texture etching of ZnO:Al by studying the HCl etching effect on ZnO:Al films sputter-deposited in a set substrate heater temperature series. With the texture-etched ZnO:Al front TCO, a single junction nc-Si:H solar cell was deposited with an initial efficiency of 8.33%. Chapter 4 starts with studying the light soaking and annealing effects on micromorph tandem solar cell. In the end, a highly stabilized bottom cell current limited tandem cell was made. The tandem shows an initial efficiency of 10.2%, and degraded only 6.9% after 1600 h of light soaking. In Chapter 5, the nc-Si:H i-layers were studied in 3 pressure and inter-electrode distance series. The correlations between plasma physics and the consequent i-layers’ properties are investigated. We show that the Raman crystalline ratio and porosity of the nc-Si:H layer have an interesting relation with the p•d product. By varying p and d, device quality nc-Si:H layer can be deposited at a high rate of 0.6 nm/s. These results in fact are a very important step for the second objective. The second objective is covered by the entire Chapter 6. All silicon layers are deposited on special aluminum

  5. Effect Of The Plasma Deposition Parameters On The Properties Of Ti/TiN Multilayers For Hard Coatings Applications

    SciTech Connect

    Saoula, N.; Henda, K.; Kesri, R.

    2008-09-23

    In this study, we present the effect of the plasma deposition parameters on the mechanical properties of Ti/TiN multilayers. The elaboration of our films has been carried out by RF-Magnetron Sputtering (13.56 MHz) under nitrogen and argon reactive plasma at low pressure. The film depositions have been done on steel substrates. The first step of our study was the optimization of the depositions conditions in order to obtain good quality films. The amount of nitrogen in the sputtering gases being fixed at 10%. The total pressure was set between 2mTorr to 10mTorr. The deposited multilayers were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and micro-indentation.

  6. Chemical vapour deposition enhanced by atmospheric microwave plasmas: a large-scale industrial process or the next nanomanufacturing tool?

    NASA Astrophysics Data System (ADS)

    Belmonte, T.; Gries, T.; Cardoso, R. P.; Arnoult, G.; Kosior, F.; Henrion, G.

    2011-04-01

    This paper describes several specific aspects of atmospheric plasma deposition carried out with a microwave resonant cavity. Deposition over a wide substrate is first studied. We show that high deposition rates (several hundreds of μm h-1) are due to localization of fluxes on the substrate by convection when slightly turbulent flows are used. Next, we describe possible routes to localize deposition over a nanometre-sized area. Scaling down atmospheric plasma deposition is possible and two strategies to reach nanometre scales are described. Finally, we study self-organization of SiO2 nanodots deposited by chemical vapour deposition at atmospheric pressure enhanced by an Ar-O2 micro-afterglow operating at high temperature (>1200 K). When the film being deposited is thin enough (~500 nm) nanodots are obtained and they can be assembled into threads to create patterned surfaces. When the coating becomes thicker (~1 µm), and for relatively high content in HMDSO, SiO2 walls forming hexagonal cells are obtained.

  7. Deposition of TiN and HfO{sub 2} in a commercial 200 mm remote plasma atomic layer deposition reactor

    SciTech Connect

    Heil, S. B. S.; Hemmen, J. L. van; Hodson, C. J.; Singh, N.; Klootwijk, J. H.; Roozeboom, F.; Sanden, M. C. M. van de; Kessels, W. M. M.

    2007-09-15

    The authors describe a remote plasma atomic layer deposition reactor (Oxford Instruments FlexAL trade mark sign ) that includes an inductively coupled plasma source and a load lock capable of handling substrates up to 200 mm in diameter. The deposition of titanium nitride (TiN) and hafnium oxide (HfO{sub 2}) is described for the combination of the metal-halide precursor TiCl{sub 4} and H{sub 2}-N{sub 2} plasma and the combination of the metallorganic precursor Hf[N(CH{sub 3})(C{sub 2}H{sub 5})]{sub 4} and O{sub 2} plasma, respectively. The influence of the plasma exposure time and substrate temperature has been studied and compositional, structural, and electrical properties are reported. TiN films with a low Cl impurity content were obtained at 350 deg. C at a growth rate of 0.35 A /cycle with an electrical resistivity as low as 150 {mu}{omega} cm. Carbon-free (detection limit <2 at. %) HfO{sub 2} films were obtained at a growth rate of 1.0 A /cycle at 290 deg. C. The thickness and resisitivity nonuniformity was <5% for the TiN and the thickness uniformality was <2% for the HfO{sub 2} films as determined over 200 mm wafers.

  8. Plasma-enhanced atomic layer deposition zinc oixde flexible thin film electronics

    NASA Astrophysics Data System (ADS)

    Zhao, Dalong

    This thesis demonstrates high performance flexible thin film electronics fabricated by low temperature process. A novel process for forming high quality stable oxide films using weak oxidant plasma-enhanced atomic layer deposition (PEALD) has been used to achieve fastest flexible oxide integrated circuits reported to date. In addition, a unique approach based on plasma-enhanced chemical vapor deposition (PECVD) silicon nitride for organic light emitting diodes (OLEDs) encapsulation at low temperature (<70 °C) is also reported. Among several low temperature deposition approaches PEALD process provides highly crystalline and dense ZnO thin films which are uniform and conformal at 200 ºC. Crossover measurement results also demonstrate the advantage of PEALD process in thin film deposition on flexible substrates. PEALD ZnO flexible TFTs have high field-effect mobility (˜ 20 cm2/V˙s) and excellent bias stress stability with ALD Al2O3 passivation. 15-stage ring oscillators with propagation delay of <20 nsec/stage have been successfully fabricated on flexible substrates. To the best of our knowledge, these are the fastest oxide-semiconductor circuits on flexible substrates reported to date, and they are about 20 times faster than the best previous report. This thesis also presents the investigation of ZnO device physics by modeling. Non-ideal ZnO device characteristics, including passivation, contacts, and output conductance, have been well modeled and verified with experimental results. Two different approaches were also proposed to extract device parameters for compact models and form the foundation for later circuit design and simulations. A TCAD ZnO model is established and can well describe the operation physics from single transistor to simple circuits. This model is verified by reasonable agreement with experimental data. Building on the results of ZnO TFTs and circuits, several ZnO based applications have been demonstrated. Microsensors with ZnO pyroFETs have

  9. Improved electrical performances of plasma-enhanced atomic layer deposited TaCxNy films by adopting Ar /H2 plasma

    NASA Astrophysics Data System (ADS)

    Park, Tae Joo; Kim, Jeong Hwan; Jang, Jae Hyuck; Na, Kwang Duk; Hwang, Cheol Seong; Kim, Jong Hoon; Kim, Gee-Man; Choi, Jae Ho; Choi, Kang Joon; Jeong, Jae Hak

    2007-12-01

    TaCxNy films were grown by a plasma-enhanced atomic layer deposition using Ta(N-t-C5H11)[N(CH3)2]3 as the precursor and H2 or Ar /H2 plasma as the reducing agent. The Ar /H2 plasma appeared to efficiently break the Ta-N bonds in the Ta precursor and formed more TaCx, which significantly decreased the resistivity of the films (˜255μΩcm ) compared with the case of the H2 plasma (˜1570μΩcm). The Ar /H2 plasma also made the films denser and efficiently eliminated the oxygen from the films. This improved the resistance against the elemental diffusion as well as the aging characteristics of the films after exposure to air.

  10. On the low-temperature growth mechanism of single walled carbon nanotubes in plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Shariat, M.; Shokri, B.; Neyts, E. C.

    2013-12-01

    Despite significant progress in single walled carbon nanotube (SWCNT) production by plasma enhanced chemical vapor deposition (PECVD), the growth mechanism in this method is not clearly understood. We employ reactive molecular dynamics simulations to investigate how plasma-based deposition allows growth at low temperature. We first investigate the SWCNT growth mechanism at low and high temperatures under conditions similar to thermal CVD and PECVD. We then show how ion bombardment during the nucleation stage increases the carbon solubility in the catalyst at low temperature. Finally, we demonstrate how moderate energy ions sputter amorphous carbon allowing for SWCNT growth at 500 K.

  11. Kinetics of structuring of submonolayer carbon coatings on silicon (100) crystals during microwave vacuum-plasma deposition

    NASA Astrophysics Data System (ADS)

    Yafarov, R. K.; Shanygin, V. Ya.

    2015-06-01

    The kinetics of self-organization of nanodomains during the deposition of submonolayer carbon coatings on (100) silicon in the microwave plasma of low-pressure ethanol vapors is studied by atomic force microscopy and scanning electron microscopy. The laws of influence of the substrate temperature and the kinetic energy of carbon-containing ions on the mechanisms of formation and structuring of the forming silicon-carbon surface phases are established. It is shown that the deposited carbon-containing nanodomains can be used as nonlithographic mask coatings for the formation of spatial low-dimensional systems on single-crystal silicon upon selective highly anisotropic plasma-chemical etching.

  12. In Situ Nanocalorimetric Investigations of Plasma Assisted Deposited Poly(ethylene oxide)-like Films by Specific Heat Spectroscopy.

    PubMed

    Madkou, Sherif; Melnichu, Iurii; Choukourov, Andrei; Krakovsky, Ivan; Biederman, Hynek; Schönhals, Andreas

    2016-04-28

    In recent years, highly cross-linked plasma polymers have started to unveil their potential in numerous biomedical applications in thin-film form. However, conventional diagnostic methods often fail due to their diverse molecular dynamics conformations. Here, glassy dynamics and the melting transition of thin PEO-like plasma assisted deposited (ppPEO) films (thickness 100 nm) were in situ studied by a combination of specific heat spectroscopy, utilizing a pJ/K sensitive ac-calorimeter chip, and composition analytical techniques. Different cross-linking densities were obtained by different plasma powers during the deposition of the films. Glassy dynamics were observed for all values of the plasma power. It was found that the glassy dynamics slows down with increasing the plasma power. Moreover, the underlying relaxation time spectra broaden indicating that the molecular motions become more heterogeneous with increasing plasma power. In a second set of the experiment, the melting behavior of the ppPEO films was studied. The melting temperature of ppPEO was found to decrease with increasing plasma power. This was explained by a decrease of the order in the crystals due to formation of chemical defects during the plasma process. PMID:27055060

  13. Evidence for the occurrence of subcutaneous oxidation during low temperature remote plasma enhanced deposition of silicon dioxide films

    NASA Astrophysics Data System (ADS)

    Fountain, G. G.; Hattangady, S. V.; Rudder, R. A.; Markunas, R. J.; Lucovsky, G.

    1989-06-01

    The paper presents evidence which indicates that a subcutaneous oxidation process takes place during remote plasma enhanced chemical vapor deposition of SiO2, which oxidizes a few monolayers of the underlying substrate. Electrical measurements on metal-insulator semiconductor (MIS) structures fabricated on Ge and GaAs materials are presented. It is found that the performance of Si metal-oxide semiconductor structures fabricated using deposited oxides degrades as the thickness of the oxide is increased.

  14. Nitrogen Plasma Instabilities and the Growth of Silicon Nitride by Electron Cyclotron Resonance Microwave Plasma Chemical Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Pool, F. S.

    1996-01-01

    Nitrogen plasma instabilities have been identified through fluctuations in the ion current density and substrate floating potential. The plasma characteristics for both nitrogen and silane-nitrogen plasmas are consistent with a transition from an underdense to overdense plasma at 0.9 and 1.0 mTorr respectively.

  15. Low temperature plasma enhanced chemical vapor deposition of thin films combining mechanical stiffness, electrical insulation, and homogeneity in microcavities

    SciTech Connect

    Peter, S.; Guenther, M.; Hauschild, D.; Richter, F.

    2010-08-15

    The deposition of hydrogenated amorphous carbon (a-C:H) as well as hydrogenated amorphous silicon carbonitride (SiCN:H) films was investigated in view of a simultaneous realization of a minimum Young's modulus (>70 GPa), a high electrical insulation ({>=}1 MV/cm), a low permittivity and the uniform coverage of microcavities with submillimeter dimensions. For the a-C:H deposition the precursors methane (CH{sub 4}) and acetylene (C{sub 2}H{sub 2}) were used, while SiCN:H films were deposited from mixtures of trimethylsilane [SiH(CH{sub 3}){sub 3}] with nitrogen and argon. To realize the deposition of micrometer thick films with the aforementioned complex requirements at substrate temperatures {<=}200 deg. C, several plasma enhanced chemical vapor deposition methods were investigated: the capacitively coupled rf discharge and the microwave electron cyclotron resonance (ECR) plasma, combined with two types of pulsed substrate bias. SiCN:H films deposited at about 1 Pa from ECR plasmas with pulsed high-voltage bias best met the requirements. Pulsed biasing with pulse periods of about 1 {mu}s and amplitudes of about -2 kV was found to be most advantageous for the conformal low temperature coating of the microtrenches, thereby ensuring the required mechanical and insulating film properties.

  16. Deposition of titanium nitride and hydroxyapatite-based biocompatible composite by reactive plasma spraying

    NASA Astrophysics Data System (ADS)

    Roşu, Radu Alexandru; Şerban, Viorel-Aurel; Bucur, Alexandra Ioana; Dragoş, Uţu

    2012-02-01

    Titanium nitride is a bioceramic material successfully used for covering medical implants due to the high hardness meaning good wear resistance. Hydroxyapatite is a bioactive ceramic that contributes to the restoration of bone tissue, which together with titanium nitride may contribute to obtaining a superior composite in terms of mechanical and bone tissue interaction matters. The paper presents the experimental results in obtaining composite layers of titanium nitride and hydroxyapatite by reactive plasma spraying in ambient atmosphere. X-ray diffraction analysis shows that in both cases of powders mixtures used (10% HA + 90% Ti; 25% HA + 75% Ti), hydroxyapatite decomposition occurred; in variant 1 the decomposition is higher compared with the second variant. Microstructure of the deposited layers was investigated using scanning electron microscope, the surfaces presenting a lamellar morphology without defects such as cracks or microcracks. Surface roughness values obtained vary as function of the spraying distance, presenting higher values at lower thermal spraying distances.

  17. Highly ionized physical vapor deposition plasma source working at very low pressure

    SciTech Connect

    Stranak, V.; Herrendorf, A.-P.; Drache, S.; Hippler, R.; Cada, M.; Hubicka, Z.; Tichy, M.

    2012-04-02

    Highly ionized discharge for physical vapor deposition at very low pressure is presented in the paper. The discharge is generated by electron cyclotron wave resonance (ECWR) which assists with ignition of high power impulse magnetron sputtering (HiPIMS) discharge. The magnetron gun (with Ti target) was built into the single-turn coil RF electrode of the ECWR facility. ECWR assistance provides pre-ionization effect which allows significant reduction of pressure during HiPIMS operation down to p = 0.05 Pa; this is nearly more than an order of magnitude lower than at typical pressure ranges of HiPIMS discharges. We can confirm that nearly all sputtered particles are ionized (only Ti{sup +} and Ti{sup ++} peaks are observed in the mass scan spectra). This corresponds well with high plasma density n{sub e} {approx} 10{sup 18} m{sup -3}, measured during the HiPIMS pulse.

  18. Highly ionized physical vapor deposition plasma source working at very low pressure

    NASA Astrophysics Data System (ADS)

    Stranak, V.; Herrendorf, A.-P.; Drache, S.; Cada, M.; Hubicka, Z.; Tichy, M.; Hippler, R.

    2012-04-01

    Highly ionized discharge for physical vapor deposition at very low pressure is presented in the paper. The discharge is generated by electron cyclotron wave resonance (ECWR) which assists with ignition of high power impulse magnetron sputtering (HiPIMS) discharge. The magnetron gun (with Ti target) was built into the single-turn coil RF electrode of the ECWR facility. ECWR assistance provides pre-ionization effect which allows significant reduction of pressure during HiPIMS operation down to p = 0.05 Pa; this is nearly more than an order of magnitude lower than at typical pressure ranges of HiPIMS discharges. We can confirm that nearly all sputtered particles are ionized (only Ti+ and Ti++ peaks are observed in the mass scan spectra). This corresponds well with high plasma density ne ˜ 1018 m-3, measured during the HiPIMS pulse.

  19. Low-temperature synthesis of graphene on nickel foil by microwave plasma chemical vapor deposition.

    PubMed

    Kim, Y; Song, W; Lee, S Y; Jeon, C; Jung, W; Kim, M; Park, C-Y

    2011-06-27

    Microwave plasma chemical vapor deposition (MPCVD) was employed to synthesize high quality centimeter scale graphene film at low temperatures. Monolayer graphene was obtained by varying the gas mixing ratio of hydrogen and methane to 80:1. Using advantages of MPCVD, the synthesis temperature was decreased from 750 °C down to 450 °C. Optical microscopy and Raman mapping images exhibited that a large area monolayer graphene was synthesized regardless of the temperatures. Since the overall transparency of 89% and low sheet resistances ranging from 590 to 1855 Ω∕sq of graphene films were achieved at considerably low synthesis temperatures, MPCVD can be adopted in manufacturing future large-area electronic devices based on graphene film. PMID:21799537

  20. Low-temperature synthesis of graphene on nickel foil by microwave plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Song, W.; Lee, S. Y.; Jeon, C.; Jung, W.; Kim, M.; Park, C.-Y.

    2011-06-01

    Microwave plasma chemical vapor deposition (MPCVD) was employed to synthesize high quality centimeter scale graphene film at low temperatures. Monolayer graphene was obtained by varying the gas mixing ratio of hydrogen and methane to 80:1. Using advantages of MPCVD, the synthesis temperature was decreased from 750 °C down to 450 °C. Optical microscopy and Raman mapping images exhibited that a large area monolayer graphene was synthesized regardless of the temperatures. Since the overall transparency of 89% and low sheet resistances ranging from 590 to 1855 Ω/sq of graphene films were achieved at considerably low synthesis temperatures, MPCVD can be adopted in manufacturing future large-area electronic devices based on graphene film.

  1. Plasma Spray Deposition of Lanthanum Phosphate and Phase Structure of the Resultant Coatings

    NASA Astrophysics Data System (ADS)

    Pragatheeswaran, A.; Ananthapadmanabhan, P. V.; Chakravarthy, Y.; Chaturvedi, Vandana; Bhandari, Subhankar; Ramachandran, K.

    2015-12-01

    Plasma-sprayed lanthanum phosphate coatings were prepared on stainless steel substrates at different input powers from 16 to 24 kW. Coatings were characterized by x-ray diffraction, scanning electron microscopy, and Fourier transformed infrared spectroscopy. Results showed that the as-sprayed coatings consist of lanthanum ortho (LaPO4), poly(La2P4O13), and oxy(La3PO7) phosphates. Subsequent heat treatment of the coatings resulted in the recombination of the La-polyphosphate and La-oxyphosphate to form LaPO4. SEM images of microstructure of the coatings and coating-substrate interface showed micro-cracks, voids, and porosity that were found to decrease with deposition power.

  2. Low-temperature synthesis of graphene on nickel foil by microwave plasma chemical vapor deposition

    SciTech Connect

    Kim, Y.; Song, W.; Lee, S. Y.; Jeon, C.; Jung, W.; Kim, M.; Park, C.-Y.

    2011-06-27

    Microwave plasma chemical vapor deposition (MPCVD) was employed to synthesize high quality centimeter scale graphene film at low temperatures. Monolayer graphene was obtained by varying the gas mixing ratio of hydrogen and methane to 80:1. Using advantages of MPCVD, the synthesis temperature was decreased from 750 deg. C down to 450 deg. C. Optical microscopy and Raman mapping images exhibited that a large area monolayer graphene was synthesized regardless of the temperatures. Since the overall transparency of 89% and low sheet resistances ranging from 590 to 1855 {Omega}/sq of graphene films were achieved at considerably low synthesis temperatures, MPCVD can be adopted in manufacturing future large-area electronic devices based on graphene film.

  3. Antifouling Transparent ZnO Thin Films Fabricated by Atmospheric Pressure Cold Plasma Deposition

    NASA Astrophysics Data System (ADS)

    Suzaki, Yoshifumi; Du, Jinlong; Yuji, Toshifumi; Miyagawa, Hayato; Ogawa, Kazufumi

    2015-09-01

    One problem with outdoor-mounted solar panels is that power generation efficiency is reduced by face plate dirt; a problem with electronic touch panels is the deterioration of screen visibility caused by finger grease stains. To solve these problems, we should fabricate antifouling surfaces which have superhydrophobic and oil-repellent properties without spoiling the transparency of the transparent substrate. In this study, an antifouling surface with both superhydrophobicity and oil-repellency was fabricated on a glass substrate by forming a fractal microstructure. The fractal microstructure was constituted of transparent silica particles 100 nm in diameter and transparent zinc-oxide columns grown on silica particles through atmospheric pressure cold plasma deposition; the sample surface was coated with a chemically adsorbed monomolecular layer. Samples were obtained which had a superhydrophobic property (with a water droplet contact angle of more than 150°) and a high average transmittance of about 90% (with wavelengths ranging from 400 nm to 780 nm).

  4. rf plasma oxidation of Ni thin films sputter deposited to generate thin nickel oxide layers

    NASA Astrophysics Data System (ADS)

    Hoey, Megan L.; Carlson, J. B.; Osgood, R. M.; Kimball, B.; Buchwald, W.

    2010-10-01

    Nickel oxide (NiO) layers were formed on silicon (Si) substrates by plasma oxidation of nickel (Ni) film lines. This ultrathin NiO layer acted as a barrier layer to conduction, and was an integral part of a metal-insulator-metal (MIM) diode, completed by depositing gold (Au) on top of the oxide. The electrical and structural properties of the NiO thin film were examined using resistivity calculations, current-voltage (I-V) measurements and cross-sectional transmission electron microscopy (XTEM) imaging. The flow rate of the oxygen gas, chamber pressure, power, and exposure time and their influence on the characteristics of the NiO thin film were studied.

  5. In situ nitrogen-doped graphene grown from polydimethylsiloxane by plasma enhanced chemical vapor deposition.

    PubMed

    Wang, Chundong; Zhou, Yungang; He, Lifang; Ng, Tsz-Wai; Hong, Guo; Wu, Qi-Hui; Gao, Fei; Lee, Chun-Sing; Zhang, Wenjun

    2013-01-21

    Due to its unique electronic properties and wide spectrum of promising applications, graphene has attracted much attention from scientists in various fields. Control and engineering of graphene's semiconducting properties is considered to be key to its applications in electronic devices. Here, we report a novel method to prepare in situ nitrogen-doped graphene by microwave plasma assisted chemical vapor deposition (CVD) using PDMS (polydimethylsiloxane) as a solid carbon source. Based on this approach, the concentration of nitrogen-doping can be easily controlled via the flow rate of nitrogen during the CVD process. X-ray photoelectron spectroscopy results indicated that the nitrogen atoms doped into the graphene lattice were mainly in the forms of pyridinic and pyrrolic structures. Moreover, first-principles calculations show that the incorporated nitrogen atoms can lead to p-type doping of graphene. This in situ approach provides a promising strategy to prepare graphene with controlled electronic properties. PMID:23203220

  6. Electrical characterization of graphene films synthesized by low-temperature microwave plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Okigawa, Yuki; Tsugawa, Kazuo; Yamada, Takatoshi; Ishihara, Masatou; Hasegawa, Masataka

    2013-10-01

    In this Letter, we discuss the results of Hall effect measurements to examine the electrical properties of the graphene films synthesized by low-temperature microwave plasma chemical vapor deposition. Van der Pauw devices with sizes of 50-100 μm were fabricated, for which we observed p-type conduction and mobility from 10 to 100 cm2/V s. To investigate the mobility dispersion, we performed Raman mapping to quantify the number of defects and the disorder in graphene films. The results suggest that the D-band/G-band intensity ratio is correlated with the mobility. Moreover, we discuss the factors controlling the mobility and how to improve the quality of the graphene films by reducing the number of defects.

  7. Plasma-Enhanced Pulsed Laser Deposition of Wide Bandgap Nitrides for Space Power Applications

    NASA Technical Reports Server (NTRS)

    Triplett, G. E., Jr.; Durbin, S. M.

    2004-01-01

    The need for a reliable, inexpensive technology for small-scale space power applications where photovoltaic or chemical battery approaches are not feasible has prompted renewed interest in radioisotope-based energy conversion devices. Although a number of devices have been developed using a variety of semiconductors, the single most limiting factor remains the overall lifetime of the radioisotope battery. Recent advances in growth techniques for ultra-wide bandgap III-nitride semiconductors provide the means to explore a new group of materials with the promise of significant radiation resistance. Additional benefits resulting from the use of ultra-wide bandgap materials include a reduction in leakage current and higher operating voltage without a loss of energy transfer efficiency. This paper describes the development of a novel plasma-enhanced pulsed laser deposition system for the growth of cubic boron nitride semiconducting thin films, which will be used to construct pn junction devices for alphavoltaic applications.

  8. In situ nitrogen-doped graphene grown from polydimethylsiloxane by plasma enhanced chemical vapor deposition

    SciTech Connect

    Wang, Chundong; Zhou, Yungang; He, Lifang; Ng, Tsz-Wai; Hong, Guo; Wu, Qi-Hui; Gao, Fei; Lee, Chun-Sing; Zhang, Wenjun

    2013-01-21

    Due to its unique electronic properties and wide spectrum of promising applications, graphene has attracted much attention from scientists in various fields. Control and engineering of graphene’s semiconducting properties is considered to be the key of its applications in electronic devices. Here, we report a novel method to prepare in situ nitrogen-doped graphene by microwave plasma assisted chemical vapor deposition (CVD) using PDMS (Polydimethylsiloxane) as a solid carbon source. Based on this approach, the concentration of nitrogen-doping can be easily controlled via the flow rate of nitrogen during the CVD process. X-ray photoelectron spectroscopy results indicated that the nitrogen atoms doped into graphene lattice were mainly in the forms of pyridinic and pyrrolic structures. Moreover, first-principles calculations show that the incorporated nitrogen atoms can lead to p-type doping of graphene. This in situ approach provides a promising strategy to prepare graphene with controlled electronic properties.

  9. Remote plasma-assisted deposition of metals onto the surface of nanocrystalline ZnO

    NASA Astrophysics Data System (ADS)

    Leal, Sergio A.; Nemashkalo, Anastasiia; Chapagain, Puskar; Pant, Shreedhar; Alarcon, Phillip; Strzhemechny, Yuri M.

    2011-10-01

    Controllable surface modification of nanoscale ZnO is crucial for many existing and future applications. We investigated the effectiveness of metal deposition using remote O2/He plasma passing through a metal mesh electrode onto the surface of ZnO nanopowders with an average grain size of 25 nm. Surface stoichiometry was monitored in situ with Auger electron spectroscopy, whereas surface optoelectronic properties were probed; also in situ, using surface photovoltage (SPV) spectroscopy. We observed a strong dependence of surface modification on the distance from the metal electrode. At short distances the metal coverage was reaching tens of percent of one monolayer. Simultaneously we observed a significant improvement of the SPV response pointing to metal-enhanced surface charge dynamics.

  10. Plasma immersion ion implantation and deposition of DLC coating for modification of orthodontic magnets

    NASA Astrophysics Data System (ADS)

    Wongsarat, W.; Sarapirom, S.; Aukkaravittayapun, S.; Jotikasthira, D.; Boonyawan, D.; Yu, L. D.

    2012-02-01

    This study was aimed to use the plasma immersion ion implantation and deposition (PIII-D) technique to form diamond-like carbon (DLC) thin films on orthodontic magnets to solve the corrosion problem. To search for the optimal material modification effect, PIII-D conditions including gases, processing time, and pulsing mode were varied. The formation of DLC films was confirmed and characterized with Raman spectra. The intensity of the remnant magnetic field of the magnets and the hardness, adhesion and thickness of the thin films were then measured. A corrosion test was carried out using clinic dental fluid. Improved benefits including a satisfying hardness, adhesion, remnant magnetic strength and corrosion resistance of the DLC coating could be achieved by using a higher interrupting time ratio and shorter processing time.

  11. High Current Emission from Patterned Aligned Carbon Nanotubes Fabricated by Plasma-Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Cui, Linfan; Chen, Jiangtao; Yang, Bingjun; Jiao, Tifeng

    2015-12-01

    Vertically, carbon nanotube (CNT) arrays were successfully fabricated on hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition using gas mixtures of acetylene (C2H2) and hydrogen (H2) with Fe/Al2O3 catalysts. The CNTs were found to be graphitized with multi-walled structures. Different H2/C2H2 gas flow rate ratio was used to investigate the effect on CNT growth, and the field emission properties were optimized. The CNT emitters exhibited excellent field emission performance (the turn-on and threshold fields were 2.1 and 2.4 V/μm, respectively). The largest emission current could reach 70 mA/cm2. The emission current was stable, and no obvious deterioration was observed during the long-term stability test of 50 h. The results were relevant for practical applications based on CNTs.

  12. High Current Emission from Patterned Aligned Carbon Nanotubes Fabricated by Plasma-Enhanced Chemical Vapor Deposition.

    PubMed

    Cui, Linfan; Chen, Jiangtao; Yang, Bingjun; Jiao, Tifeng

    2015-12-01

    Vertically, carbon nanotube (CNT) arrays were successfully fabricated on hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition using gas mixtures of acetylene (C2H2) and hydrogen (H2) with Fe/Al2O3 catalysts. The CNTs were found to be graphitized with multi-walled structures. Different H2/C2H2 gas flow rate ratio was used to investigate the effect on CNT growth, and the field emission properties were optimized. The CNT emitters exhibited excellent field emission performance (the turn-on and threshold fields were 2.1 and 2.4 V/μm, respectively). The largest emission current could reach 70 mA/cm(2). The emission current was stable, and no obvious deterioration was observed during the long-term stability test of 50 h. The results were relevant for practical applications based on CNTs. PMID:26666912

  13. Homogeneous nanocrystalline cubic silicon carbide films prepared by inductively coupled plasma chemical vapor deposition.

    PubMed

    Cheng, Qijin; Xu, S; Long, Jidong; Huang, Shiyong; Guo, Jun

    2007-11-21

    Silicon carbide films with different carbon concentrations x(C) have been synthesized by inductively coupled plasma chemical vapor deposition from a SiH(4)/CH(4)/H(2) gas mixture at a low substrate temperature of 500 °C. The characteristics of the films were studied by x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared absorption spectroscopy, and Raman spectroscopy. Our experimental results show that, at x(C) = 49 at.%, the film is made up of homogeneous nanocrystalline cubic silicon carbide without any phase of silicon, graphite, or diamond crystallites/clusters. The average size of SiC crystallites is approximately 6 nm. At a lower value of x(C), polycrystalline silicon and amorphous silicon carbide coexist in the films. At a higher value of x(C), amorphous carbon and silicon carbide coexist in the films. PMID:21730481

  14. Diffusivity measurements in plasma deposited zirconia. A study with photoreflectance and infrared microscopy

    NASA Astrophysics Data System (ADS)

    Bisson, Jean-François; Poulain, Martine; Fournier, Danièle; Labastie-Coyrehourcq, Karine

    1999-03-01

    Thermal diffusivity measurements were performed on plasma deposited zirconia coatings for gas turbine engines. First, spatially resolved infrared detection was used in order to obtain a global thermal behavior of the coating, accounting for the solid phase and the crack network. Then, we tried to probe separately thermal diffusivity of the solid phase only with photoreflectance microscopy. Due to its significant thermal expansion coefficient and the strong thermal mismatch with the metallic coating, obtaining a trustworthy ZrO2 thermal diffusivity estimate is difficult. A methodology, using both the phase and the amplitude data, is presented which allows to extract a reliable estimate for ZrO2. The local thermal diffusivity estimate is found to be higher than the effective thermal diffusivity of the whole barrier but the obtained value is still lower than measurements done on bulk material with similar Y2O3 content, suggesting that the crack network is still participating to heat transfer at that scale.

  15. Stress hysteresis and mechanical properties of plasma-enhanced chemical vapor deposited dielectric films

    NASA Astrophysics Data System (ADS)

    Thurn, Jeremy; Cook, Robert F.; Kamarajugadda, Mallika; Bozeman, Steven P.; Stearns, Laura C.

    2004-02-01

    A comprehensive survey is described of the responses of three plasma-enhanced chemical vapor deposited dielectric film systems to thermal cycling and indentation contact. All three films—silicon oxide, silicon nitride, and silicon oxy-nitride—exhibited significant nonequilibrium permanent changes in film stress on thermal cycling or annealing. The linear relationship between stress and temperature changed after the films were annealed at 300 °C, representing a structural alteration in the film reflecting a change in coefficient of thermal expansion or biaxial modulus. A double-substrate method was used to deduce both thermoelastic properties before and after the anneal of selected films and the results were compared with the modulus deconvoluted from small-scale depth-sensing indentation experiments (nanoindentation). Rutherford backscattering spectrometry and hydrogen forward scattering were used to deduce the composition of the films and it was found that all the films contained significant amounts of hydrogen.

  16. Enhanced stability of Cu-BTC MOF via perfluorohexane plasma-enhanced chemical vapor deposition.

    PubMed

    Decoste, Jared B; Peterson, Gregory W; Smith, Martin W; Stone, Corinne A; Willis, Colin R

    2012-01-25

    Metal organic frameworks (MOFs) are a leading class of porous materials for a wide variety of applications, but many of them have been shown to be unstable toward water. Cu-BTC (1,3,5 benzenetricarboxylic acid, BTC) was treated with a plasma-enhanced chemical vapor deposition (PECVD) of perfluorohexane creating a hydrophobic form of Cu-BTC. It was found that the treated Cu-BTC could withstand high humidity and even submersion in water much better than unperturbed Cu-BTC. Through Monte Carlo simulations it was found that perfluorohexane sites itself in such a way within Cu-BTC as to prevent the formation of water clusters, hence preventing the decomposition of Cu-BTC by water. This PECVD of perfluorohexane could be exploited to widen the scope of practical applications of Cu-BTC and other MOFs. PMID:22239201

  17. Perovskite solar cells based on nanocolumnar plasma-deposited ZnO thin films.

    PubMed

    Ramos, F Javier; López-Santos, Maria C; Guillén, Elena; Nazeeruddin, Mohammad Khaja; Grätzel, Michael; Gonzalez-Elipe, Agustin R; Ahmad, Shahzada

    2014-04-14

    ZnO thin films having a nanocolumnar microstructure are grown by plasma-enhanced chemical vapor deposition at 423 K on pre-treated fluorine-doped tin oxide (FTO) substrates. The films consist of c-axis-oriented wurtzite ZnO nanocolumns with well-defined microstructure and crystallinity. By sensitizing CH3NH3PbI3 on these photoanodes a power conversion of 4.8% is obtained for solid-state solar cells. Poly(triarylamine) is found to be less effective when used as the hole-transport material, compared to 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD), while the higher annealing temperature of the perovskite leads to a better infiltration in the nanocolumnar structure and an enhancement of the cell efficiency. PMID:24643984

  18. Carbon nanowalls grown by microwave plasma enhanced chemical vapor deposition during the carbonization of polyacrylonitrile fibers

    SciTech Connect

    Li Jiangling; Su Shi; Kundrat, Vojtech; Abbot, Andrew M.; Ye, Haitao; Zhou Lei; Mushtaq, Fajer; Ouyang Defang; James, David; Roberts, Darren

    2013-01-14

    We used microwave plasma enhanced chemical vapor deposition (MPECVD) to carbonize an electrospun polyacrylonitrile (PAN) precursor to form carbon fibers. Scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the fibers at different evolution stages. It was found that MPECVD-carbonized PAN fibers do not exhibit any significant change in the fiber diameter, whilst conventionally carbonized PAN fibers show a 33% reduction in the fiber diameter. An additional coating of carbon nanowalls (CNWs) was formed on the surface of the carbonized PAN fibers during the MPECVD process without the assistance of any metallic catalysts. The result presented here may have a potential to develop a novel, economical, and straightforward approach towards the mass production of carbon fibrous materials containing CNWs.

  19. Structural and mechanical properties of Al–C–N films deposited at room temperature by plasma focus device

    NASA Astrophysics Data System (ADS)

    Z, A. Umar; R, Ahmad; R, S. Rawat; M, A. Baig; J, Siddiqui; T, Hussain

    2016-07-01

    The Al–C–N films are deposited on Si substrates by using a dense plasma focus (DPF) device with aluminum fitted central electrode (anode) and by operating the device with CH4/N2 gas admixture ratio of 1:1. XRD results verify the crystalline AlN (111) and Al3CON (110) phase formation of the films deposited using multiple shots. The elemental compositions as well as chemical states of the deposited Al–C–N films are studied using XPS analysis, which affirm Al–N, C–C, and C–N bonding. The FESEM analysis reveals that the deposited films are composed of nanoparticles and nanoparticle agglomerates. The size of the agglomerates increases at a higher number of focus deposition shots for multiple shot depositions. Nanoindentation results reveal the variation in mechanical properties (nanohardness and elastic modulus) of Al–C–N films deposited with multiple shots. The highest values of nanohardness and elastic modulus are found to be about 11 and 185 GPa, respectively, for the film deposited with 30 focus deposition shots. The mechanical properties of the films deposited using multiple shots are related to the Al content and C–N bonding.

  20. Hollow electrode enhanced radio frequency glow plasma and its application to the chemical vapor deposition of microcrystalline silicon

    SciTech Connect

    Tabuchi, Toshihiro; Mizukami, Hiroyuki; Takashiri, Masayuki

    2004-09-01

    A hollow electrode enhanced radio frequency (rf) glow plasma excitation technique and its application to the chemical vapor deposition of microcrystalline silicon films have been studied. In this technique, the reactor has two types of hollow structure. One is a hollow counterelectrode, and the other serves as both a hollow counterelectrode and a hollow rf electrode. The application of these discharge types to semiconductor processing is studied in the case of plasma enhanced chemical vapor deposition of hydrogenated microcrystalline silicon thin films. High crystallinity, photosensitivity and a maximum deposition rate of 6.0 nm/s can all be achieved at plasma excitation frequency of 13.56 MHz and substrate temperature of 300 deg. C. Properties of these plasmas are investigated by observing the plasma emission pattern, optical emission spectrum analysis and electrical parameters of the rf electrode. It is found that the plasma technique using both types of hollow discharge not only results in higher intensity of SiH{sup *} and H{alpha} but also in much smaller self-bias voltage of the rf electrode. Faster processing of device grade hydrogenated microcrystalline silicon films can also be achieved under lower rf power compared to use of the hollow counterelectrode technique alone.

  1. Blood compatibility of titanium-based coatings prepared by metal plasma immersion ion implantation and deposition

    NASA Astrophysics Data System (ADS)

    Tsyganov, I.; Maitz, M. F.; Wieser, E.

    2004-07-01

    Titanium with its natural oxide is known to be generally good biocompatible; and therefore, the suitability of some Ti-based coatings as coating for blood-contacting implants is analyzed. Layers of pure Ti, Ti oxynitrides (TiN 1- xO x with x=0.25, 0.50, and 0.75), and Ti oxides were deposited on oxidized Si from a plasma produced by cathodic arc evaporation under addition of N 2 and/or O 2 to the ambient near the substrate. The oxynitrides are crystalline with the fcc structure of TiN up to x=0.25. For x=0.5, a two-phase system of fcc TiN and fcc TiO has been found. In dependence on the deposition parameters, amorphous and crystalline layers (anatase + brookite or rutile) of TiO 2 have been obtained. The rutile layers were doped by implantation of P. The amorphous TiO 2 layers were implanted with Cr. To study the correlation between structure of the coating and blood compatibility, the clotting time of blood plasma as well as the adhesion and activation of blood platelets on the surface was investigated. TiN and oxynitrides showed the longest clotting time compared to rutile. Minimum platelet adhesion has been observed for pure TiO 2. Contrasting tendencies in the dependence of clotting time and platelet adhesion on the microstructure have been stated. However, for P +-doped rutile, both enhanced clotting time and improved platelet adhesion were observed. Platelet adherence and activation always showed similar trends.

  2. Argon–germane in situ plasma clean for reduced temperature Ge on Si epitaxy by high density plasma chemical vapor deposition

    SciTech Connect

    Douglas, Erica A.; Sheng, Josephine J.; Verley, Jason C.; Carroll, Malcolm S.

    2015-06-04

    We found that the demand for integration of near infrared optoelectronic functionality with silicon complementary metal oxide semiconductor (CMOS) technology has for many years motivated the investigation of low temperature germanium on silicon deposition processes. Our work describes the development of a high density plasma chemical vapor deposition process that uses a low temperature (<460 °C) in situ germane/argon plasma surface preparation step for epitaxial growth of germanium on silicon. It is shown that the germane/argon plasma treatment sufficiently removes SiOx and carbon at the surface to enable germanium epitaxy. Finally, the use of this surface preparation step demonstrates an alternative way to produce germanium epitaxy at reduced temperatures, a key enabler for increased flexibility of integration with CMOS back-end-of-line fabrication.

  3. Argon–germane in situ plasma clean for reduced temperature Ge on Si epitaxy by high density plasma chemical vapor deposition

    DOE PAGESBeta

    Douglas, Erica A.; Sheng, Josephine J.; Verley, Jason C.; Carroll, Malcolm S.

    2015-06-04

    We found that the demand for integration of near infrared optoelectronic functionality with silicon complementary metal oxide semiconductor (CMOS) technology has for many years motivated the investigation of low temperature germanium on silicon deposition processes. Our work describes the development of a high density plasma chemical vapor deposition process that uses a low temperature (<460 °C) in situ germane/argon plasma surface preparation step for epitaxial growth of germanium on silicon. It is shown that the germane/argon plasma treatment sufficiently removes SiOx and carbon at the surface to enable germanium epitaxy. Finally, the use of this surface preparation step demonstrates anmore » alternative way to produce germanium epitaxy at reduced temperatures, a key enabler for increased flexibility of integration with CMOS back-end-of-line fabrication.« less

  4. A solid-state nuclear magnetic resonance study of post-plasma reactions in organosilicone microwave plasma-enhanced chemical vapor deposition (PECVD) coatings.

    PubMed

    Hall, Colin J; Ponnusamy, Thirunavukkarasu; Murphy, Peter J; Lindberg, Mats; Antzutkin, Oleg N; Griesser, Hans J

    2014-06-11

    Plasma-polymerized organosilicone coatings can be used to impart abrasion resistance and barrier properties to plastic substrates such as polycarbonate. Coating rates suitable for industrial-scale deposition, up to 100 nm/s, can be achieved through the use of microwave plasma-enhanced chemical vapor deposition (PECVD), with optimal process vapors such as tetramethyldisiloxane (TMDSO) and oxygen. However, it has been found that under certain deposition conditions, such coatings are subject to post-plasma changes; crazing or cracking can occur anytime from days to months after deposition. To understand the cause of the crazing and its dependence on processing plasma parameters, the effects of post-plasma reactions on the chemical bonding structure of coatings deposited with varying TMDSO-to-O2 ratios was studied with (29)Si and (13)C solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) using both single-pulse and cross-polarization techniques. The coatings showed complex chemical compositions significantly altered from the parent monomer. (29)Si MAS NMR spectra revealed four main groups of resonance lines, which correspond to four siloxane moieties (i.e., mono (M), di (D), tri (T), and quaternary (Q)) and how they are bound to oxygen. Quantitative measurements showed that the ratio of TMDSO to oxygen could shift the chemical structure of the coating from 39% to 55% in Q-type bonds and from 28% to 16% for D-type bonds. Post-plasma reactions were found to produce changes in relative intensities of (29)Si resonance lines. The NMR data were complemented by Fourier transform infrared (FTIR) spectroscopy. Together, these techniques have shown that the bonding environment of Si is drastically altered by varying the TMDSO-to-O2 ratio during PECVD, and that post-plasma reactions increase the cross-link density of the silicon-oxygen network. It appears that Si-H and Si-OH chemical groups are the most susceptible to post-plasma reactions. Coatings produced at a

  5. Diamond thin films grown by microwave plasma assisted chemical vapor deposition

    SciTech Connect

    Leksono, M.

    1991-09-05

    Undoped and boron doped diamond thin films have been successfully grown by microwave plasma chemical vapor deposition from CH{sub 4}, H{sub 2}, and B{sub 2}H{sub 6}. The films were characterized using x- ray diffraction techniques, Raman and infrared spectroscopies, scanning electron microscopy, secondary ion mass spectrometry, and various electrical measurements. The deposition rates of the diamond films were found to increase with the CH{sub 4} concentration, substrate temperature, and/or pressure, and at 1.0% methane, 900{degrees}C, and 35 Torr, the value was measured to be 0.87 {mu}m/hour. The deposition rate for boron doped diamond films, decreases as the diborane concentration increases. The morphologies of the undoped diamond films are strongly related to the deposition parameters. As the temperature increases from 840 to 925 C, the film morphology changes from cubo-octahedron to cubic structures, while as the CH{sub 4} concentration increases from 0.5 to 1.0%, the morphology changes from triangular (111) faces with a weak preferred orientation to square (100) faces. At 2.0% Ch{sub 4} or higher the films become microcrystalline with cauliflower structures. Scanning electron microscopy analyses also demonstrate that selective deposition of undoped diamond films has been successfully achieved using a lift-off process with a resolution of at least 2 {mu}m. The x-ray diffraction and Raman spectra demonstrate that high quality diamond films have been achieved. The concentration of the nondiamond phases in the films grown at 1.0% CH{sub 4} can be estimated from the Raman spectra to be at less than 0.2% and increases with the CH{sub 4} concentration. The Raman spectra of the boron doped diamond films also indicate that the presence of boron tends to suppress the nondiamond phases in the films. Infrared spectra of the undoped diamond films show very weak CH stretch peaks which suggest that the hydrogen concentration is very low.

  6. Effect of energy deposition rate on plasma expansion characteristics and nanoparticle generation by electrical explosion of conductors

    NASA Astrophysics Data System (ADS)

    Sahoo, Somanand; Saxena, Alok K.; Kaushik, Trilok C.; Gupta, Satish C.

    2015-12-01

    The process of electrical explosion of metal conductors has been used to produce nano particles under normal atmospheric conditions. The impact of average rate of energy deposition, overheat factor on size distribution of particles and expansion characteristics of plasma generated from exploding conductors have been experimentally investigated. The particle size was characterized by TEM and XRD while expansion rate was measured using streak photography.The geometric mean diameter of size distribution was found to be influenced by rate of energy deposition in the conductors. It is observed that higher the rate of energy deposition, higher will be the expansion velocity, and smaller will be the size of particles formed.

  7. Organometallic chemical vapor deposition of silicon nitride films enhanced by atomic nitrogen generated from surface-wave plasma

    SciTech Connect

    Okada, H.; Kato, M.; Ishimaru, T.; Sekiguchi, H.; Wakahara, A.; Furukawa, M.

    2014-02-20

    Organometallic chemical vapor deposition of silicon nitride films enhanced by atomic nitrogen generated from surface-wave plasma is investigated. Feasibility of precursors of triethylsilane (TES) and bis(dimethylamino)dimethylsilane (BDMADMS) is discussed based on a calculation of bond energies by computer simulation. Refractive indices of 1.81 and 1.71 are obtained for deposited films with TES and BDMADMS, respectively. X-ray photoelectron spectroscopy (XPS) analysis of the deposited film revealed that TES-based film coincides with the stoichiometric thermal silicon nitride.

  8. Rutile-structured TiO{sub 2} deposited by plasma enhanced atomic layer deposition using tetrakis(dimethylamino)titanium precursor on in-situ oxidized Ru electrode

    SciTech Connect

    Pointet, John; Gonon, Patrice; Latu-Romain, Lawrence; Bsiesy, Ahmad Vallée, Christophe

    2014-01-15

    In this work, tetrakis(dimethylamino)titanium precursor as well as in-situ oxidized ruthenium bottom electrode were used to grow rutile-structured titanium dioxide thin layers by plasma enhanced atomic layer deposition. Metal–insulator–metal capacitors have been elaborated in order to study the electrical properties of the device. It is shown that this process leads to devices exhibiting excellent results in terms of dielectric constant and leakage current.

  9. Transparent conductive indium zinc oxide films prepared by pulsed plasma deposition

    SciTech Connect

    Wan Runlai; Yang Ming; Zhou Qianfei; Zhang Qun

    2012-11-15

    Transparent conductive indium zinc oxide films were prepared by pulsed plasma deposition from a ceramic target (90 wt. % In{sub 2}O{sub 3} and 10 wt. % ZnO). The dependences of film properties upon the substrate temperature was investigated using characterization methods including x-ray diffraction, atomic force microscope, Hall measurement, ultraviolet-visible spectroscopy, and x-ray photoelectron spectroscopy. The films grown at room temperature had a rather smooth surface due to the amorphous structure, with a root mean square roughness of less than 1 nm. The atomic ratio of Zn/(Zn + In) in these films is 15.3 at. %, which is close to that in the target, and the chemical states of indium and zinc atoms were In{sup 3+} and Zn{sup 2+}, respectively. The films deposited on a substrate with a temperature of 200 Degree-Sign C exhibited polycrystalline structure and a preferred growth orientation along the (222) plane. Here the electrical properties were improved due to the better crystallinity, with the films exhibiting a minimum resistivity value of 4.2 Multiplication-Sign 10{sup -4}{Omega} cm, a maximum carrier mobility of 45 cm{sup 2} V{sup -1} s{sup -1}, and an optical transmittance over 80% in the visible region.

  10. Characterization of diamond-like nanocomposite thin films grown by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Santra, T. S.; Liu, C. H.; Bhattacharyya, T. K.; Patel, P.; Barik, T. K.

    2010-06-01

    Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of CC, CH, SiC, and SiH bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio ID/IG. Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS).

  11. Plasma-assisted physical vapor deposition surface treatments for tribological control

    NASA Technical Reports Server (NTRS)

    Spalvins, Talivaldis

    1990-01-01

    In any mechanical or engineering system where contacting surfaces are in relative motion, adhesion, wear, and friction affect reliability and performance. With the advancement of space age transportation systems, the tribological requirements have dramatically increased. This is due to the optimized design, precision tolerance requirements, and high reliability expected for solid lubricating films in order to withstand hostile operating conditions (vacuum, high-low temperatures, high loads, and space radiation). For these problem areas the ion-assisted deposition/modification processes (plasma-based and ion beam techniques) offer the greatest potential for the synthesis of thin films and the tailoring of adherence and chemical and structural properties for optimized tribological performance. The present practices and new approaches of applying soft solid lubricant and hard wear resistant films to engineering substrates are reviewed. The ion bombardment treatments have increased film adherence, lowered friction coefficients, and enhanced wear life of the solid lubricating films such as the dichalcogenides (MoS2) and the soft metals (Au, Ag, Pb). Currently, sputtering is the preferred method of applying MoS2 films; and ion plating, the soft metallic films. Ultralow friction coefficients (less than 0.01) were achieved with sputtered MoS2. Further, new diamond-like carbon and BN lubricating films are being developed by using the ion assisted deposition techniques.

  12. Characterization of diamond-like nanocomposite thin films grown by plasma enhanced chemical vapor deposition

    SciTech Connect

    Santra, T. S.; Liu, C. H.; Bhattacharyya, T. K.; Patel, P.; Barik, T. K.

    2010-06-15

    Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of C-C, C-H, Si-C, and Si-H bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio I{sub D}/I{sub G}. Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS).

  13. Plasma deposition of amorphous silicon carbide thin films irradiated with neutrons

    NASA Astrophysics Data System (ADS)

    Huran, J.; Bohacek, P.; Kucera, M.; Kleinova, A.; Sasinkova, V.; IEE SAS, Bratislava, Slovakia Team; Polymer Institute, SAS, Bratislava, Slovakia Team; Institute of Chemistry, SAS, Bratislava, Slovakia Team

    2015-09-01

    Amorphous silicon carbide and N-doped silicon carbide thin films were deposited on P-type Si(100) wafer by plasma enhanced chemical vapor deposition (PECVD) technology using silane, methane, ammonium and argon gases. The concentration of elements in the films was determined by RBS and ERDA method. Chemical compositions were analyzed by FTIR spectroscopy. Photoluminescence properties were studied by photoluminescence spectroscopy (PL). Irradiation of samples with various neutron fluencies was performed at room temperature. The films contain silicon, carbon, hydrogen, nitrogen and small amount of oxygen. From the IR spectra, the films contained Si-C, Si-H, C-H, Si-N, N-H and Si-O bonds. No significance effect on the IR spectra after neutron irradiation was observed. PL spectroscopy results of films showed decreasing PL intensity after neutron irradiation and PL intensity decreased with increased neutron fluencies. The measured current of the prepared structures increased after irradiation with neutrons and rise up with neutron fluencies.

  14. Ultralow-k silicon containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Jin, Yoonyoung; Ajmera, P. K.; Lee, G. S.; Singh, Varshni

    2005-09-01

    Low dielectric constant materials as interlayer dielectrics (ILDs) offer a way to reduce the RC time delay in high-performance ultra-large-scale integration (ULSI) circuits. Fluorocarbon films containing silicon have been developed for interlayer applications below 50-nm linewidth technology. The preparation of the films was carried out by plasma-enhanced chemical vapor deposition (PECVD) using gas precursors of tetrafluorocarbon as the source of active species and disilane (5 vol.% in helium) as a reducing agent to control the ratio of F/C in the films. The basic properties of the low dielectric constant (low-k) interlayer dielectric films are studied as a function of the fabrication process parameters. The electrical, mechanical, chemical, and thermal properties were evaluated including dielectric constant, surface planarity, hardness, residual stress, chemical bond structure, and shrinkage upon heat treatments. The deposition process conditions were optimized for film thermal stability while maintaining a relative dielectric value as low as 2.0. The average breakdown field strength was 4.74 MV/cm. The optical energy gap was in the range 2.2 2.4 eV. The hardness and residual stress in the optimized processed SiCF films were, respectively, measured to be in the range 1.4 1.78 GPa and in the range 11.6 23.2 MPa of compressive stress.

  15. Microbridge testing of plasma-enhanced chemical-vapor deposited silicon oxide films on silicon wafers

    NASA Astrophysics Data System (ADS)

    Cao, Zhiqiang; Zhang, Tong-Yi; Zhang, Xin

    2005-05-01

    Plasma-enhanced chemical-vapor deposited (PECVD) silane-based oxides (SiOx) have been widely used in both microelectronics and microelectromechanical systems (MEMS) to form electrical and/or mechanical components. In this paper, a nanoindentation-based microbridge testing method is developed to measure both the residual stresses and Young's modulus of PECVD SiOx films on silicon wafers. Theoretically, we considered both the substrate deformation and residual stress in the thin film and derived a closed formula of deflection versus load. The formula fitted the experimental curves almost perfectly, from which the residual stresses and Young's modulus of the film were determined. Experimentally, freestanding microbridges made of PECVD SiOx films were fabricated using the silicon undercut bulk micromachining technique. Some microbridges were subjected to rapid thermal annealing (RTA) at a temperature of 400 °C, 600 °C, or 800 °C to simulate the thermal process in the device fabrication. The results showed that the as-deposited PECVD SiOx films had a residual stress of -155±17MPa and a Young's modulus of 74.8±3.3GPa. After the RTA, Young's modulus remained relatively unchanged at around 75 GPa, however, significant residual stress hysteresis was found in all the films. A microstructure-based mechanism was then applied to explain the experimental results of the residual stress changes in the PECVD SiOx films after the thermal annealing.

  16. Passivation of aluminum nanoparticles by plasma-enhanced chemical vapor deposition for energetic nanomaterials.

    PubMed

    Shahravan, Anaram; Desai, Tapan; Matsoukas, Themis

    2014-05-28

    We have produced passivating coatings on 80-nm aluminum particles by plasma-enhanced chemical vapor deposition (PECVD). Three organic precursors--isopropyl alcohol, toluene, and perfluorodecalin--were used to fabricate thin films with thicknesses ranging from 5 nm to 30 nm. The coated samples and one untreated sample were exposed to 85% humidity at 25 °C for two months, and the active Al content was determined by thermogravimetric analysis (TGA) in the presence of oxygen. The results were compared with an uncoated sample stored in a glovebox under argon for the same period. We find that all three coatings provide protection against humidity, compared to the control, and their efficacy ranks in the following order: isopropyl alcohol < toluene < perfluorodecalin. This order also correlates with increasing water contact angle of the three solid coatings. The amount of heat released in the oxidation, measured by differential scanning calorimetry (DSC), was found to increase in the same order. Perfluorodecalin resulted in providing the best protection, and it produced the maximum enthalpy of combustion, ΔH = 4.65 kJ/g. This value is higher than that of uncoated aluminum stored in the glovebox, indicating that the coatings promote more complete oxidation of the core. Overall, we conclude that the plasma polymer coatings of this study are suitable passivating thin film for aluminum nanoparticles by providing protection against oxidation while facilitating the complete oxidation of the metallic core at elevated temperature. PMID:24787245

  17. Epithelial cell morphology and adhesion on diamond films deposited and chemically modified by plasma processes.

    PubMed

    Rezek, Bohuslav; Ukraintsev, Egor; Krátká, Marie; Taylor, Andrew; Fendrych, Frantisek; Mandys, Vaclav

    2014-09-01

    The authors show that nanocrystalline diamond (NCD) thin films prepared by microwave plasma enhanced chemical vapor deposition apparatus with a linear antenna delivery system are well compatible with epithelial cells (5637 human bladder carcinoma) and significantly improve the cell adhesion compared to reference glass substrates. This is attributed to better adhesion of adsorbed layers to diamond as observed by atomic force microscopy (AFM) beneath the cells. Moreover, the cell morphology can be adjusted by appropriate surface treatment of diamond by using hydrogen and oxygen plasma. Cell bodies, cytoplasmic rims, and filopodia were characterized by Peakforce AFM. Oxidized NCD films perform better than other substrates under all conditions (96% of cells adhered well). A thin adsorbed layer formed from culture medium and supplemented with fetal bovine serum (FBS) covered the diamond surface and played an important role in the cell adhesion. Nevertheless, 50-100 nm large aggregates formed from the RPMI medium without FBS facilitated cell adhesion also on hydrophobic hydrogenated NCD (increase from 23% to 61%). The authors discuss applicability for biomedical uses. PMID:25280853

  18. Growth of ultrananocrystalline diamond film by DC Arcjet plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Chen, G. C.; Li, B.; Yan, Z. Q.; Liu, J.; Lu, F. X.; Ye, H.

    2012-06-01

    Self-standing diamond films were grown by DC Arcjet plasma enhanced chemical vapor deposition (CVD). The feed gasses were Ar/H2/CH4, in which the flow ratio of CH4 to H2 (F/F) was varied from 5% to 20%. Two distinct morphologies were observed by scanning electron microscope (SEM), i.e. the "pineapple-like" morphology and the "cauliflower-like" morphology. It was found that the morphologies of the as-grown films are strongly dependent on the flow ratio of CH4 to H2 in the feed gasses. High resolution transmission electron microscope (HRTEM) survey results revealed that there were nanocrystalline grains within the "pineapple-like" films whilst there were ultrananocrystalline grains within "cauliflower-like" films. X-ray diffraction (XRD) results suggested that (110) crystalline plane was the dominant surface in the "cauliflower-like" films whilst (100) crystalline plane was the dominant surface in the "pineapple-like" films. Raman spectroscopy revealed that nanostructured carbon features could be observed in both types of films. Plasma diagnosis was carried out in order to understand the morphology dependent growth mechanism. It could be concluded that the film morphology was strongly influenced by the density of gas phases. The gradient of C2 radical was found to be different along the growth direction under the different growth conditions.

  19. Characterization of Yttria-Stabilized Zirconia Coatings Deposited by Low-Pressure Plasma Spraying

    NASA Astrophysics Data System (ADS)

    He, Peng-jiang; Yin, Shuo; Song, Chen; Lapostolle, Frédéric; Liao, Han-lin

    2016-02-01

    The research presented here aimed to apply plasma spraying at a low pressure of 100 Pa for fabricating the columnar structure or dense coatings. These coatings with different structures were elaborated from the vapor condensation and molten droplets, respectively, using the agglomerated YSZ powders and a relatively low power commercial F4-VB torch. It was shown that the crystallite size of coating deposited from the vapor condensation at a spraying distance of 200 mm was reduced to 17.1 nm from 43.7 nm of the feedstock. Observations indicated that a thin columnar structured coating was produced out of the line of sight of projection. In the line of sight of projection, the hybrid structured coating was obtained. The relatively dense coating was fabricated using a specifically designed extended nozzle. Investigations by means of optical emission spectroscopy were performed to analyze the nature of the plasma jet with YSZ powders. The Vickers microhardness was also conducted. It was found that the relatively dense coating showed a higher value in comparison to the hybrid structure coating, up to 1273 ± 56 Hv100g.

  20. Analyzing the contents of residual and plasma-supporting gases inside a vacuum deposition unit chamber

    NASA Astrophysics Data System (ADS)

    Mikheev, A. Ye; Kharlamov, V. A.; Kruchek, S. D.; Cherniatina, A. A.; Khomenko, I. I.

    2015-01-01

    The paper describes a quadruple mass-spectrometer method, which is used to analyze the content of residual gas in a vacuum chamber of the ARM NTM (Automatised Working Area) ion-plasma unit. This unit is used to perfect the magnetron deposition process for coating radio-reflecting surfaces. The intake of pure argon into the chamber revealed up to 0.3 % of impurities in the plasma-supporting gas, including 0.02 % of water and oxygen. A significant presence of hydrocarbon gases is explained by the presence of solvents sorbed in rubber washers, joints of internal equipment, and other components inside the chamber. In order to decrease the level of impurities in the plasmasupporting atmosphere inside the chamber and improve the composition and properties of the coatings, it is necessary to take additional measures to cleanse and degas the surface of the chamber from condensation products and hydrocarbon compounds. To provide a minimal level of impurities in the coated surfaces it is vital to clean and degas the surfaces of the chamber, removing residual moisture and hydrocarbon compounds.

  1. Plasma-Enhanced Atomic Layer Deposition of Silicon Nitride Using a Novel Silylamine Precursor.

    PubMed

    Park, Jae-Min; Jang, Se Jin; Yusup, Luchana L; Lee, Won-Jun; Lee, Sang-Ick

    2016-08-17

    We report the plasma-enhanced atomic layer deposition (PEALD) of silicon nitride thin film using a silylamine compound as the silicon precursor. A series of silylamine compounds were designed by replacing SiH3 groups in trisilylamine by dimethylaminomethylsilyl or trimethylsilyl groups to obtain sufficient thermal stability. The silylamine compounds were synthesized through redistribution, amino-substitution, lithiation, and silylation reactions. Among them, bis(dimethylaminomethylsilyl)trimethylsilyl amine (C9H29N3Si3, DTDN2-H2) was selected as the silicon precursor because of the lowest bond dissociation energy and sufficient vapor pressures. The energies for adsorption and reaction of DTDN2-H2 with the silicon nitride surface were also calculated by density functional theory. PEALD silicon nitride thin films were prepared using DTDN2-H2 and N2 plasma. The PEALD process window was between 250 and 400 °C with a growth rate of 0.36 Å/cycle. The best film quality was obtained at 400 °C with a RF power of 100 W. The PEALD film prepared showed good bottom and sidewall coverages of ∼80% and ∼73%, respectively, on a trench-patterned wafer with an aspect ratio of 5.5. PMID:27447839

  2. Plasma-enhanced chemical vapor deposition synthesis of vertically oriented graphene nanosheets.

    PubMed

    Bo, Zheng; Yang, Yong; Chen, Junhong; Yu, Kehan; Yan, Jianhua; Cen, Kefa

    2013-06-21

    Vertically oriented graphene (VG) nanosheets have attracted growing interest for a wide range of applications, from energy storage, catalysis and field emission to gas sensing, due to their unique orientation, exposed sharp edges, non-stacking morphology, and huge surface-to-volume ratio. Plasma-enhanced chemical vapor deposition (PECVD) has emerged as a key method for VG synthesis; however, controllable growth of VG with desirable characteristics for specific applications remains a challenge. This paper attempts to summarize the state-of-the-art research on PECVD growth of VG nanosheets to provide guidelines on the design of plasma sources and operation parameters, and to offer a perspective on outstanding challenges that need to be overcome to enable commercial applications of VG. The review starts with an overview of various types of existing PECVD processes for VG growth, and then moves on to research on the influences of feedstock gas, temperature, and pressure on VG growth, substrate pretreatment, the growth of VG patterns on planar substrates, and VG growth on cylindrical and carbon nanotube (CNT) substrates. The review ends with a discussion on challenges and future directions for PECVD growth of VG. PMID:23670071

  3. Plasma-enhanced chemical vapor deposition synthesis of vertically oriented graphene nanosheets

    NASA Astrophysics Data System (ADS)

    Bo, Zheng; Yang, Yong; Chen, Junhong; Yu, Kehan; Yan, Jianhua; Cen, Kefa

    2013-05-01

    Vertically oriented graphene (VG) nanosheets have attracted growing interest for a wide range of applications, from energy storage, catalysis and field emission to gas sensing, due to their unique orientation, exposed sharp edges, non-stacking morphology, and huge surface-to-volume ratio. Plasma-enhanced chemical vapor deposition (PECVD) has emerged as a key method for VG synthesis; however, controllable growth of VG with desirable characteristics for specific applications remains a challenge. This paper attempts to summarize the state-of-the-art research on PECVD growth of VG nanosheets to provide guidelines on the design of plasma sources and operation parameters, and to offer a perspective on outstanding challenges that need to be overcome to enable commercial applications of VG. The review starts with an overview of various types of existing PECVD processes for VG growth, and then moves on to research on the influences of feedstock gas, temperature, and pressure on VG growth, substrate pretreatment, the growth of VG patterns on planar substrates, and VG growth on cylindrical and carbon nanotube (CNT) substrates. The review ends with a discussion on challenges and future directions for PECVD growth of VG.

  4. Atomistic analysis of the mechanism of hydrogen diffusion in plasma-deposited amorphous silicon thin films

    NASA Astrophysics Data System (ADS)

    Valipa, Mayur S.; Maroudas, Dimitrios

    2005-12-01

    We report the mechanism and activation barrier of H diffusion on the surface and in the bulk of plasma-deposited hydrogenated amorphous silicon (a-Si:H) films during postdeposition exposure of the films to H atoms from a H2 plasma. Our study is based on molecular-dynamics simulations of repeated impingement of H atoms on surfaces of smooth a-Si :H films over the temperature range 475-800K. The H diffusion mechanism is identical both on the a-Si :H surface and in the bulk a-Si :H film. Specifically, the H atom diffuses rapidly through a floating-bond-mediated migration process; this floating bond accompanies the H atom as it hops from one Si atom to another. The Si atoms between which the H hops during its diffusion are typically either very weakly bonded or not bonded to each other. The calculated activation barrier for H diffusion is only 0.10eV.

  5. Thermal stability studies of plasma sprayed yttrium oxide coatings deposited on pure tantalum substrate

    NASA Astrophysics Data System (ADS)

    Nagaraj, A.; Anupama, P.; Mukherjee, Jaya; Sreekumar, K. P.; Satpute, R. U.; Padmanabhan, P. V. A.; Gantayet, L. M.

    2010-02-01

    Plasma sprayed Yttrium oxide is used for coating of crucibles and moulds that are used at high temperature to handle highly reactive molten metals like uranium, titanium, chromium, and beryllium. The alloy bond layer is severely attacked by the molten metal. This commonly used layer contributes to the impurity addition to the pure liquid metal. Yttrium oxide was deposited on tantalum substrates (25 mm × 10mm × 1mm thk and 40 mm × 8mm × 1mm thk) by atmospheric plasma spray technique with out any bond coat using optimized coating parameters. Resistance to thermal shock was evaluated by subjecting the coated specimens, to controlled heating and cooling cycles between 300K to 1600K in an induction furnace in argon atmosphere having <= 0.1ppm of oxygen. The experiments were designed to examine the sample tokens by both destructive and non-destructive techniques, after a predetermined number of thermal cycles. The results upto 24 thermal cycles of 25 mm × 10mm × 1mm thk coupons and upto 6 cycles of 40 mm × 8mm × 1mm thk coupons are discussed. The coatings produced with the optimized parameters were found to exhibit excellent thermal shock resistance.

  6. Low Friction-Coefficient TiBCN Nanocomposite Coatings Prepared by Cathode Arc Plasma Deposition

    NASA Astrophysics Data System (ADS)

    LIN, Baozhu; WANG, Lingling; WAN, Qiang; YAN, Shaojian; WANG, Zesong; YANG, Bing; FU, Dejun

    2015-03-01

    TiBCN nanocomposite coatings were deposited on cemented carbide and Si (100) by a cathode arc plasma system, in which TiB2 cathodes were used in mixture gases of N2 and C2H2. X-ray diffraction shows that TiB2 and Ti2B5 peaks enhance at low flow rates of C2H2, but they shrink when the flow rate is over 200 sccm. An increase of deposition rate was obtained from different TiBCN thicknesses for the same deposition time measured by scanning electron microscopy. Atomic force microscopy shows that the surface roughnesses are ˜10 nm and ˜20 nm at C2H2 flow rates of 0-100 sccm and of 150-300 sccm, respectively. High resolution transmission electron microscopy and X-ray photoelectron spectroscopy show that the coatings consist of nanocrystal phases Ti2BB, TiB2 and TiN, and amorphous phase carbon and BN. The average crystal sizes embedded in the amorphous matrices are 200 nm and 10 nm at C2H2 flow rates of 200 sccm and 300 sccm, respectively. In Raman spectra, the D- and G-bands increase with C2H2 flows at low flow rates, but weaken at high flow rates. The microhardness of the coatings decreases from 28.6 GPa to 20 GPa as the C2H2 increases from 0 sccm to 300 sccm, and the ball-on-disk measurement shows a dramatic decrease of the friction coefficient from 0.84 to 0.13. The reason for the reduced hardness and friction coefficient with the change of C2H2 flow rates is discussed. supported by National Natural Science Foundation of China (Nos. 11350110206, 11375133) and the Fundamental Research Funds for the Central Universities of China (No. 11275141)

  7. Electrical Properties and Physical Characteristics of Polycrystalline Diamond Films Deposited in a Microwave Plasma Disk Reactor

    NASA Astrophysics Data System (ADS)

    Huang, Bohr-Ran

    1992-01-01

    This work experimentally investigates techniques for high quality diamond synthesis and develops means for electrical and physical characterization of the films. The films are deposited by plasma assisted chemical vapor deposition using a methane/hydrogen plasma in a microwave plasma disk reactor system. Both a diamond past nucleation method and a diamond powder nucleation method are studied in this research. Although as indicated by Raman spectroscopy both methods produced similar quality diamond films, the powder nucleation method produced fine grain, sub-micron sized crystallite, films whereas the past nucleation method produced large grain, several-micrometer size crystallite, films. For powder polished films, all metallic contacts were ohmic. These samples were used to explore the high electric field properties of diamond. It was discovered that for fields larger than approximately 1 times 10^5 V/cm the electrical properties are dominated by defects, where defect is used generically for either an impurity or a structural defect. For low electric fields, the electrical conductivity was constant which resulted in ohmic behavior. But for high fields, the conductivity was field activated according to Poole's law. This behavior was modeled as being due to ionizable defects and indicates that there is approximately one ionizable defect per 10,000 host atoms. As a result of such defects, the breakdown field for these films was somewhat less than 1 times 10^6 V/cm. A large concentration of defects is compatible with the observation of ohmic contact behavior regardless of metallic work function since contact space charge layers would be sufficiently thin to allow tunneling. Non-ohmic, Schottky barrier contacts were achievable on the past polished films. For Al/diamond/silicon structures diode characteristics were observed. These I-V characteristics were modeled as an ideal Schottky barrier diode in series with bulk diamond, for which the property of the bulk diamond

  8. Al{sub 2}O{sub 3} multi-density layer structure as a moisture permeation barrier deposited by radio frequency remote plasma atomic layer deposition

    SciTech Connect

    Jung, Hyunsoo; Jeon, Heeyoung; Choi, Hagyoung; Ham, Giyul; Shin, Seokyoon; Jeon, Hyeongtag

    2014-02-21

    Al{sub 2}O{sub 3} films deposited by remote plasma atomic layer deposition have been used for thin film encapsulation of organic light emitting diode. In this study, a multi-density layer structure consisting of two Al{sub 2}O{sub 3} layers with different densities are deposited with different deposition conditions of O{sub 2} plasma reactant time. This structure improves moisture permeation barrier characteristics, as confirmed by a water vapor transmission rate (WVTR) test. The lowest WVTR of the multi-density layer structure was 4.7 × 10{sup −5} gm{sup −2} day{sup −1}, which is one order of magnitude less than WVTR for the reference single-density Al{sub 2}O{sub 3} layer. This improvement is attributed to the location mismatch of paths for atmospheric gases, such as O{sub 2} and H{sub 2}O, in the film due to different densities in the layers. This mechanism is analyzed by high resolution transmission electron microscopy, elastic recoil detection, and angle resolved X-ray photoelectron spectroscopy. These results confirmed that the multi-density layer structure exhibits very good characteristics as an encapsulation layer via location mismatch of paths for H{sub 2}O and O{sub 2} between the two layers.

  9. Fabrication of metallic single electron transistors featuring plasma enhanced atomic layer deposition of tunnel barriers

    NASA Astrophysics Data System (ADS)

    Karbasian, Golnaz

    The continuing increase of the device density in integrated circuits (ICs) gives rise to the high level of power that is dissipated per unit area and consequently a high temperature in the circuits. Since temperature affects the performance and reliability of the circuits, minimization of the energy consumption in logic devices is now the center of attention. According to the International Technology Roadmaps for Semiconductors (ITRS), single electron transistors (SETs) hold the promise of achieving the lowest power of any known logic device, as low as 1x10-18 J per switching event. Moreover, SETs are the most sensitive electrometers to date, and are capable of detecting a fraction of an electron charge. Despite their low power consumption and high sensitivity for charge detection, room temperature operation of these devices is quite challenging mainly due to lithographical constraints in fabricating structures with the required dimensions of less than 10 nm. Silicon based SETs have been reported to operate at room temperature. However, they all suffer from significant variation in batch-to-batch performance, low fabrication yield, and temperature-dependent tunnel barrier height. In this project, we explored the fabrication of SETs featuring metal-insulator-metal (MIM) tunnel junctions. While Si-based SETs suffer from undesirable effect of dopants that result in irregularities in the device behavior, in metal-based SETs the device components (tunnel barrier, island, and the leads) are well-defined. Therefore, metal SETs are potentially more predictable in behavior, making them easier to incorporate into circuits, and easier to check against theoretical models. Here, the proposed fabrication method takes advantage of unique properties of chemical mechanical polishing (CMP) and plasma enhanced atomic layer deposition (PEALD). Chemical mechanical polishing provides a path for tuning the dimensions of the tunnel junctions, surpassing the limits imposed by electron beam

  10. Atomic layer deposition precursor step repetition and surface plasma pretreatment influence on semiconductor–insulator–semiconductor heterojunction solar cell

    SciTech Connect

    Talkenberg, Florian Illhardt, Stefan; Schmidl, Gabriele; Schleusener, Alexander; Sivakov, Vladimir; Radnóczi, György Zoltán; Pécz, Béla; Dikhanbayev, Kadyrjan; Mussabek, Gauhar; Gudovskikh, Alexander

    2015-07-15

    Semiconductor–insulator–semiconductor heterojunction solar cells were prepared using atomic layer deposition (ALD) technique. The silicon surface was treated with oxygen and hydrogen plasma in different orders before dielectric layer deposition. A plasma-enhanced ALD process was applied to deposit dielectric Al{sub 2}O{sub 3} on the plasma pretreated n-type Si(100) substrate. Aluminum doped zinc oxide (Al:ZnO or AZO) was deposited by thermal ALD and serves as transparent conductive oxide. Based on transmission electron microscopy studies the presence of thin silicon oxide (SiO{sub x}) layer was detected at the Si/Al{sub 2}O{sub 3} interface. The SiO{sub x} formation depends on the initial growth behavior of Al{sub 2}O{sub 3} and has significant influence on solar cell parameters. The authors demonstrate that a hydrogen plasma pretreatment and a precursor dose step repetition of a single precursor improve the initial growth behavior of Al{sub 2}O{sub 3} and avoid the SiO{sub x} generation. Furthermore, it improves the solar cell performance, which indicates a change of the Si/Al{sub 2}O{sub 3} interface states.

  11. Analysis of photoluminescence background of Raman spectra of carbon nanotips grown by plasma-enhanced chemical vapor deposition

    SciTech Connect

    Wang, B. B.; Ostrikov, K.; Tsakadze, Z. L.; Xu, S.

    2009-07-01

    Carbon nanotips with different structures were synthesized by plasma-enhanced hot filament chemical vapor deposition and plasma-enhanced chemical vapor deposition using different deposition conditions, and they were investigated by scanning electron microscopy and Raman spectroscopy. The results indicate that the photoluminescence background of the Raman spectra is different for different carbon nanotips. Additionally, the Raman spectra of the carbon nanotips synthesized using nitrogen-containing gas precursors show a peak located at about 2120 cm{sup -1} besides the common D and G peaks. The observed difference in the photoluminescence background is related to the growth mechanisms, structural properties, and surface morphology of a-C:H and a-C:H:N nanotips, in particular, the sizes of the emissive tips.

  12. Characteristics of indium oxide plasma filters deposited by atmospheric pressure CVD

    SciTech Connect

    Langlois, E.; Murthy, S.D.; Bhat, I.; Gutmann, R.; Brown, E.; Dziendziel, R.; Freeman, M.; Choudhury, N.

    1995-07-01

    Thin films of undoped and tin-doped In{sub 2}O{sub 3} are being investigated for use as plasma filters in spectral control applications for thermal photovoltaic cells. These films are required to exhibit high reflectance at wavelengths longer than the plasma wavelength {lambda}{sub p}, high transmittance at wavelengths shorter than {lambda}{sub p} and low absorption throughout the spectrum. Both types of films were grown via atmospheric pressure chemical vapor deposition (APCVD) on Si (100) and fused silica substrates using trimethylindium (TMI), tetraethyltin (TET), and oxygen as the precursors. Fourier Transform InfraRed (FTIR) spectroscopy was used to measure the filter transmittance and reflectance between 1.8--20 {micro}m. Nominal conditions used during the growth of undoped In{sub 2}O{sub 3} were a substrate temperature of 450 C and partial pressures of 1.4 {times} 10{sup {minus}4} atm. and 1 {times} 10{sup {minus}3} atm. for TMI and O{sub 2} respectively. The O{sub 2}/TMI partial pressure ratio and substrate temperature were systematically varied to control the filter characteristics. The plasma wavelength {lambda}{sub p} was found to be a sensitive function of these parameters. Post-growth annealing of the films was done in inert as well as air ambient at elevated temperatures, but was found to have no beneficial effect. Tin-doped In{sub 2}O{sub 3} was grown under similar conditions as above, with a typical TET partial pressure of 4 {times} 10{sup {minus}6} atm. Here also, the material properties and consequently the optical response were found to be strongly dependent on growth conditions such as O{sub 2} and TET partial pressures. Both undoped and tin-doped In{sub 2}O{sub 3} grown on fused silica exhibited enhanced transmittance due to the close matching of refractive indices of In{sub 2}O{sub 3} and silica. X-ray diffractometer measurements indicated that all these films were polycrystalline and highly textured towards the (111) direction. The best

  13. Redeposition in plasma-assisted atomic layer deposition: Silicon nitride film quality ruled by the gas residence time

    SciTech Connect

    Knoops, Harm C. M. E-mail: w.m.m.kessels@tue.nl; Peuter, K. de; Kessels, W. M. M. E-mail: w.m.m.kessels@tue.nl

    2015-07-06

    The requirements on the material properties and growth control of silicon nitride (SiN{sub x}) spacer films in transistors are becoming ever more stringent as scaling of transistor structures continues. One method to deposit high-quality films with excellent control is atomic layer deposition (ALD). However, depositing SiN{sub x} by ALD has turned out to be very challenging. In this work, it is shown that the plasma gas residence time τ is a key parameter for the deposition of SiN{sub x} by plasma-assisted ALD and that this parameter can be linked to a so-called “redeposition effect”. This previously ignored effect, which takes place during the plasma step, is the dissociation of reaction products in the plasma and the subsequent redeposition of reaction-product fragments on the surface. For SiN{sub x} ALD using SiH{sub 2}(NH{sup t}Bu){sub 2} as precursor and N{sub 2} plasma as reactant, the gas residence time τ was found to determine both SiN{sub x} film quality and the resulting growth per cycle. It is shown that redeposition can be minimized by using a short residence time resulting in high-quality films with a high wet-etch resistance (i.e., a wet-etch rate of 0.5 nm/min in buffered HF solution). Due to the fundamental nature of the redeposition effect, it is expected to play a role in many more plasma-assisted ALD processes.

  14. Atmospheric pressure plasma chemical vapor deposition reactor for 100 mm wafers, optimized for minimum contamination at low gas flow rates

    NASA Astrophysics Data System (ADS)

    Anand, Venu; Nair, Aswathi R.; Shivashankar, S. A.; Mohan Rao, G.

    2015-08-01

    Gas discharge plasmas used for thinfilm deposition by plasma-enhanced chemical vapor deposition (PECVD) must be devoid of contaminants, like dust or active species which disturb the intended chemical reaction. In atmospheric pressure plasma systems employing an inert gas, the main source of such contamination is the residual air inside the system. To enable the construction of an atmospheric pressure plasma (APP) system with minimal contamination, we have carried out fluid dynamic simulation of the APP chamber into which an inert gas is injected at different mass flow rates. On the basis of the simulation results, we have designed and built a simple, scaled APP system, which is capable of holding a 100 mm substrate wafer, so that the presence of air (contamination) in the APP chamber is minimized with as low a flow rate of argon as possible. This is examined systematically by examining optical emission from the plasma as a function of inert gas flow rate. It is found that optical emission from the plasma shows the presence of atmospheric air, if the inlet argon flow rate is lowered below 300 sccm. That there is minimal contamination of the APP reactor built here, was verified by conducting an atmospheric pressure PECVD process under acetylene flow, combined with argon flow at 100 sccm and 500 sccm. The deposition of a polymer coating is confirmed by infrared spectroscopy. X-ray photoelectron spectroscopy shows that the polymer coating contains only 5% of oxygen, which is comparable to the oxygen content in polymer deposits obtained in low-pressure PECVD systems.

  15. Effects of Ammonia Plasma Treatment on the Electrical Properties of Plasma-Enhanced Chemical Vapor Deposition Amorphous Hydrogenated Silicon Carbide Films

    NASA Astrophysics Data System (ADS)

    Li, Yan-Way; Chen, Chia-Fu

    2002-09-01

    Amorphous hydrogenated silicon carbide (a-SiC:H) films were deposited from a mixture of silane and methane gases using the plasma-enhanced chemical vapor deposition (PECVD) process. The properties of the film, following ammonia plasma treatment, are reported. A lower silane flow rate reduces the refractive index, but increases the carbon content and the optical band gap. Increasing the carbon concentration of the a-SiC:H films reduces the dielectric constant. The films were treated with ammonia plasma for various treatment periods. The original film has a smooth surface with a roughness of 0.231 nm, but increasing the ammonia plasma treatment period gradually roughens the surface. The chemical bonding nature of the a-SiC:H films with higher silicon content was investigated by X-ray photoelectron spectroscopy. Various nitrogen ionization species reacted with Si to promote the formation of silicon nitride. As a result, although the dielectric constant of the a-SiC:H films increased slightly, the leakage current density declined as the ammonia plasma treatment time increased.

  16. Physics of Plasma-Based Ion Implantation&Deposition (PBIID)and High Power Impulse Magnetron Sputtering (HIPIMS): A Comparison

    SciTech Connect

    Anders, Andre

    2007-08-28

    The emerging technology of High Power Impulse MagnetronSputtering (HIPIMS) has much in common with the more establishedtechnology of Plasma Based Ion Implantation&Deposition (PBIID):both use pulsed plasmas, the pulsed sheath periodically evolves andcollapses, the plasma-sheath system interacts with the pulse-drivingpower supply, the plasma parameters are affected by the power dissipated,surface atoms are sputtered and secondary electrons are emitted, etc.Therefore, both fields of science and technology could learn from eachother, which has not been fully explored. On the other hand, there aresignificant differences, too. Most importantly, the operation of HIPIMSheavilyrelies on the presence of a strong magnetic field, confiningelectrons and causing their ExB drift, which is closed for typicalmagnetron configurations. Second, at the high peak power levels used forHIPIMS, 1 kW/cm2 or greater averaged over the target area, the sputteredmaterial greatly affects plasma generation. For PBIID, in contrast,plasma generation and ion processing of the surface (ion implantation,etching, and deposition) are considered rela-tively independentprocesses. Third, secondary electron emission is generally considered anuisance for PBIID, especially at high voltages, whereas it is a criticalingredient to the operation of HIPIMS. Fourth, the voltages in PBIID areoften higher than in HIPIMS. For the first three reasons listed above,modelling of PBIID seems to be easier and could give some guidance forfuture HIPIMS models, which, clearly, will be more involved.

  17. Film Characteristics of Low-Temperature Plasma-Enhanced Chemical Vapor Deposition Silicon Dioxide Using Tetraisocyanatesilane and Oxygen

    NASA Astrophysics Data System (ADS)

    Idris, Irman; Sugiura, Osamu

    1998-12-01

    Silicon dioxide films were deposited in a parallel-plate electrode RF plasma-enhanced chemical vapor deposition (PECVD) system using hydrogen-free tetraisocyanatesilane (TICS) and oxygen. The deposition parameters were varied systematically, and the films were characterized by measuring infrared spectra, density, etch rate, refractive index, and current-voltage (I V) and capacitance-voltage (C V) characteristics, as well as by examining their annealing behavior. At 300°C and a TICS partial pressure ratio of 20%, a water-free and hydroxyl-group-free SiO2 film was obtained. The film density, BHF etch rate, refractive index, resistivity, and dielectric constant were 2.3 g/cm3, 330 nm/min, 1.46, 7×1015 Ω·cm, and 3.6, respectively. The film quality degraded and, simultaneously, the film absorbed moisture from the atmosphere with decreasing deposition temperature; however, the quality can be improved by reducing TICS partial pressure. SiO2 films could be deposited even at 15°C, and had a resistivity of about 1013Ω·cm. Infrared measurements showed that SiO2 films deposited from TICS/O2 contained less absorbed water than those deposited from hydrogen-containing source materials at the same deposition temperature.

  18. Effects of copper-plasma deposition on weathering properties of wood surfaces

    NASA Astrophysics Data System (ADS)

    Gascón-Garrido, P.; Mainusch, N.; Militz, H.; Viöl, W.; Mai, C.

    2016-03-01

    Thin layers of copper micro-particles were deposited on the surfaces of Scots pine (Pinus sylvestris L.) micro-veneers using atmospheric pressure plasma to improve the resistance of the surfaces to weathering. Three different loadings of copper were established. Micro-veneers were exposed to artificial weathering in a QUV weathering tester for 0, 24, 48, 96 and 144 h following the standard EN 927-6 [1]. Mass losses after each exposure showed significant differences between copper coated and untreated micro-veneers. Tensile strength was assessed at zero span (z-strength) and finite span (f-strength) under dry conditions (20 °C, 65% RH). During 48 h, micro-veneers lost their z-strength progressively. In contrast, copper coating at highest loading imparts a photo-protective effect to wood micro-veneers during 144 h exhibiting z-strength retention of 95%. F-strength losses were similar in all copper treated and untreated micro-veneers up to 96 h. However, after 144 h, copper coated micro-veneers at highest loading showed significantly greater strength retention of 56%, while untreated micro-veneers exhibited only 38%. Infrared spectroscopy suggested that copper coating does not stabilize lignin. Inductively Coupled Plasma revealed that micro-veneers coated with the highest loading exhibited the lowest percentage of copper loss. Blue stain resistance of copper coated Scots pine following the guidelines of EN 152 [2] was performed. Additional test with different position of the coated surface was also assessed. Copper coating reduced fungal growth when coated surface is exposed in contact with vermiculite. Spores of Aureobasidium pullulans were not able to germinate on the copper coated surface positioned uppermost.

  19. Structure and hydrogen bonding in plasma deposited polymorphous silicon thin films

    NASA Astrophysics Data System (ADS)

    Lebib, S.; Cabarrocas, P. Roca I.

    2004-04-01

    We present a detailed study of the structure and hydrogen bonding in silicon thin films ranging from amorphous to microcrystalline. We emphasize the results for hydrogenated polymorphous silicon films obtained under plasma conditions close to powder formation where silicon clusters and nanocrystals contribute to growth. Fourier Transform Infra-Red (FTIR) spectroscopy, Raman spectroscopy, X-Ray-Diffraction (XRD), and hydrogen evolution measurements are performed to characterize the hydrogen bonding and the structure of the films in their as-deposited state and after isochronal annealing at increasing temperature in the range of 300 to 600 °C. While Raman spectroscopy and XRD give an average information on the structure of the films, without clear evidence of the presence of crystallites in the polymorphous films, infrared spectroscopy and hydrogen evolution measurements which probe the local hydrogen related structure are shown to be perfectly adapted to characterize polymorphous silicon films. In particular, IR spectroscopy measurements, reveal the presence of a stretching band at 2030 cm^{-1}, associated with a peak at 873 cm^{-1} in the bending region and a downward shift in the Si-H wagging mode from 640 cm^{-1} to 622 cm^{-1}. We attribute the 2030 cm^{-1} mode to the presence of hydrogen bonded at the surface of the plasma produced silicon clusters and nanocrystals. This assignment is supported by hydrogen evolution measurements in which a sharp low-temperature hydrogen evolution peak appears at around 420 °C followed by up to five peaks at higher temperatures. This particular hydrogen bonding in polymorphous silicon films is also supported by isochronal annealing studies which show that the bands at 2030 cm^{-1} and 873 cm^{-1} vanish at annealing temperatures corresponding to the low temperature hydrogen evolution peak. Based on these results and their correlation with the hydrogen-related material structure, we propose a picture for the structure of

  20. Interaction of deuterium plasma with sputter-deposited tungsten nitride films

    NASA Astrophysics Data System (ADS)

    Gao, L.; Jacob, W.; Meisl, G.; Schwarz-Selinger, T.; Höschen, T.; von Toussaint, U.; Dürbeck, T.

    2016-01-01

    Magnetron-sputtered tungsten nitride (WNx) films were used as a model system to study the behaviour of re-deposited WNx layers which could form in fusion devices with tungsten (W) wall during nitrogen seeding. The interaction of such WNx layers with deuterium (D) plasmas was investigated in dedicated laboratory experiments. D retention and N removal due to D plasma exposure (D flux: 9.9  ×  1019 D m-2 s-1, ion energy 215 eV) at different temperatures were measured with ion beam analysis (IBA). Low-energy argon sputtering followed by IBA was applied to resolve the D distribution in the top-most surface of WNx with significantly improved depth resolution compared with the standard D depth profiling method by nuclear reaction analysis. Experimentally determined thicknesses for the penetration of D in WNx were compared with the penetration depth for D calculated in SDTrimSP simulations. Results show that D is only retained within the ion penetration range for samples exposed at 300 K. In contrast to the 300 K case, D diffuses beyond the implantation depth in a sample exposed at 600 K. However, the D penetration depth is much lower than in pure W at comparable conditions. The total amount of retained D in WNx at 600 K is by 50% lower than for implantation at 300 K with the same D fluence. Nitrogen is removed only within the D ion range.

  1. Plasma-enhanced chemical vapor deposition and characterization of high-permittivity hafnium and zirconium silicate films

    NASA Astrophysics Data System (ADS)

    Kato, Hiromitsu; Nango, Tomohiro; Miyagawa, Takeshi; Katagiri, Takahiro; Seol, Kwang Soo; Ohki, Yoshimichi

    2002-07-01

    Deposition of hafnium silicate films with various hafnium contents was tried by plasma-enhanced chemical vapor deposition using tetraethoxysilane and a hafnium alkoxide. From x-ray photoelectron spectroscopy, the deposited films are confirmed to be silicate with Hf-O-Si bonds but without any Hf-Si bonds. The permittivity calculated from the capacitance of the accumulation layer increases monotonically with an increase in the hafnium content, whereas the optical band gap energy estimated from vacuum ultraviolet absorption spectra decreases. Similar results were obtained from zirconium silicate films deposited using tetraethoxysilane and a zirconium alkoxide. If we compare the films with the same hafnium or zirconium content, the hafnium silicate exhibits a higher permittivity and a larger band gap energy than the zirconium silicate.

  2. Low-temperature-deposited insulating films of silicon nitride by reactive sputtering and plasma-enhanced CVD: Comparison of characteristics

    NASA Astrophysics Data System (ADS)

    Sato, Masaru; Takeyama, Mayumi B.; Nakata, Yoshihiro; Kobayashi, Yasushi; Nakamura, Tomoji; Noya, Atsushi

    2016-04-01

    The characteristics of SiN x films deposited by reactive sputtering and plasma-enhanced chemical vapor deposition (PECVD) are examined to obtain high-density films at low deposition temperatures. PECVD SiN x films deposited at 200 °C show low densities of 2.14-2.20 g/cm3 regardless of their composition, while their refractive index varies depending on their composition. PECVD requires the substrate temperature to obtain high-density films, because a possible cause of low-density films is the amount of Si-H bond, rather than that of N-H bond, in the films originating from hydrogen incorporated by the insufficient decomposition of SiH4 molecules at low temperatures. The sputtered SiN x films with high density are obtained at a temperature lower than 200 °C and considered a promising candidate for insulating films at low process temperatures.

  3. Physical/chemical properties of tin oxide thin film transistors prepared using plasma-enhanced atomic layer deposition

    SciTech Connect

    Lee, Byung Kook; Jung, Eunae; Kim, Seok Hwan; Moon, Dae Chul; Lee, Sun Sook; Park, Bo Keun; Hwang, Jin Ha; Chung, Taek-Mo; Kim, Chang Gyoun; An, Ki-Seok

    2012-10-15

    Thin film transistors (TFTs) with tin oxide films as the channel layer were fabricated by means of plasma enhanced atomic layer deposition (PE-ALD). The as-deposited tin oxide films show n-type conductivity and a nano-crystalline structure of SnO{sub 2}. Notwithstanding the relatively low deposition temperatures of 70, 100, and 130 °C, the bottom gate tin oxide TFTs show an on/off drain current ratio of 10{sup 6} while the device mobility values were increased from 2.31 cm{sup 2}/V s to 6.24 cm{sup 2}/V s upon increasing the deposition temperature of the tin oxide films.

  4. Deposition and composition-control of Mn-doped ZnO thin films by combinatorial pulsed laser deposition using two delayed plasma plumes

    SciTech Connect

    Sanchez-Ake, C.; Camacho, R.; Moreno, L.

    2012-08-15

    Thin films of ZnO doped with manganese were deposited by double-beam, combinatorial pulsed laser deposition. The laser-induced plasmas were studied by means of fast photography and using a Langmuir probe, whereas the films were analyzed by x-ray-diffraction and energy-dispersive x-ray spectroscopy. The effect of the relative delay between plasma plumes on the characteristics of the films was analyzed. It was found that using this parameter, it is possible to control the dopant content keeping the oriented wurtzite structure of the films. The minimum content of Mn was found for plume delays between 0 and 10 {mu}s as the interaction between plasmas scatters the dopant species away from the substrate, thus reducing the incorporation of Mn into the films. Results suggest that for delays shorter than {approx}100 {mu}s, the expansion of the second plume through the region behind the first plume affects the composition of the film.

  5. Control of the Radial Energy Deposition Profile in an Open Magnetic Trap During Electron Cyclotron Plasma Heating

    NASA Astrophysics Data System (ADS)

    Gospodchikov, E. D.; Smolyakova, O. B.

    2016-05-01

    We propose a method for controlling the radial profile of electron cyclotron plasma heating in an axisymmetric magnetic mirror by using minor perturbations of the magnetic field of the mirror. The method is based on the analysis of the ray trajectories behavior near the surface of the electron cyclotron resonance. A way to produce such perturbations by supplementing the system with an additional "quadrupole" pair of magnetic coils is also proposed. The possibility to improve the coupling of radiation with the plasma in an open trap is demonstrated, as well as the possibility to control the energy deposition profile by means of small variations of the current in the additional coils for two basic scenarios of electron cyclotron plasma heating, specifically, longitudinal launching of microwave radiation to the magnetic mirror region and trapping of obliquely launched radiation by the inhomogeneous magnetized-plasma column.

  6. Control of the Radial Energy Deposition Profile in an Open Magnetic Trap During Electron Cyclotron Plasma Heating

    NASA Astrophysics Data System (ADS)

    Gospodchikov, E. D.; Smolyakova, O. B.

    2016-04-01

    We propose a method for controlling the radial profile of electron cyclotron plasma heating in an axisymmetric magnetic mirror by using minor perturbations of the magnetic field of the mirror. The method is based on the analysis of the ray trajectories behavior near the surface of the electron cyclotron resonance. A way to produce such perturbations by supplementing the system with an additional "quadrupole" pair of magnetic coils is also proposed. The possibility to improve the coupling of radiation with the plasma in an open trap is demonstrated, as well as the possibility to control the energy deposition profile by means of small variations of the current in the additional coils for two basic scenarios of electron cyclotron plasma heating, specifically, longitudinal launching of microwave radiation to the magnetic mirror region and trapping of obliquely launched radiation by the inhomogeneous magnetized-plasma column.

  7. nm- thick conformal pore-sealing of self-assembled mesoporous silica by plasma-assisted atomic layer deposition

    PubMed Central

    Jiang, Ying-Bing; Liu, Nanguo; Gerung, Henry; Cecchi, Joseph L.; Brinker, C. Jeffrey

    2009-01-01

    On a porous substrate, regular atomic layer deposition (ALD) not only takes place on top of the substrate but also penetrates into the internal porosity. Here we report a plasma-assisted process in which the ALD precursors are chosen to be non-reactive unless triggered by plasma, so that ALD can be spatially defined by the supply of plasma irradiation. Since plasma cannot penetrate within the internal porosity, ALD has been successfully confined to the immediate surface. This not only gives a possible solution for sealing of porous low dielectric constant films with a conformal layer of nm-scale thickness, but also enables us to progressively reduce the pore size of mesoporous materials in a sub-Å/cycle fashion for membrane formation. PMID:16925407

  8. Thermal Shock Properties of Yttria-Stabilized Zirconia Coatings Deposited Using Low-Energy Very Low Pressure Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Zhu, Lin; Zhang, Nannan; Bolot, Rodolphe; Liao, Hanlin; Coddet, Christian

    2015-08-01

    Yttria-stabilized zirconia (YSZ) coatings have been frequently used as a thermal protective layer on the metal or alloy component surfaces. In the present study, ZrO2-7%Y2O3 thermal barrier coatings (TBCs) were successfully deposited by DC (direct current) plasma spray process under very low pressure conditions (less than 1 mbar) using low-energy plasma guns F4-VB and F100. The experiments were performed to evaluate the thermal shock resistance of different TBC specimens which were heated to 1373 K at a high-temperature cycling furnace and held for 0.5 h, followed by air cooling at room temperature for 0.2 h. For comparison, a corresponding atmospheric plasma spray (APS) counterpart was also elaborated to carry out the similar experiments. The results indicated that the very low pressure plasma spray (VLPPS) coatings displayed better thermal shock resistance. Moreover, the failure mechanism of the coatings was elucidated.

  9. The deposition of titanium dioxide nanoparticles by means of a hollow cathode plasma jet in dc regime

    NASA Astrophysics Data System (ADS)

    Perekrestov, R.; Kudrna, P.; Tichý, M.

    2015-06-01

    TiO2 nanoparticles are being investigated in this work. Nanoparticles were obtained in Ar plasma on monocrystaline Si(111) substrate by means of a gas-phase deposition using a low pressure hollow cathode plasma jet. The material of the cathode is pure titanium. Oxygen was introduced separately from argon through an inlet in the chamber. The nanoparticle growth mechanism is qualitatively discussed. The morphology of the surfaces of thin films was investigated by an atomic force microscope. The chemical composition of the thin films was investigated by means of an energy-dispersive x-ray analysis and x-ray photoelectron spectroscopy. A cylindrical Langmuir probe and a fiber optic thermometer was used for measurements of plasma parameters and neutral gas temperature respectively. The relationship between plasma parameters and the films’ morphology is particularly explained.

  10. Surface chemistry of plasma-assisted atomic layer deposition of Al2O3 studied by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Langereis, E.; Keijmel, J.; van de Sanden, M. C. M.; Kessels, W. M. M.

    2008-06-01

    The surface groups created during plasma-assisted atomic layer deposition (ALD) of Al2O3 were studied by infrared spectroscopy. For temperatures in the range of 25-150°C, -CH3 and -OH were unveiled as dominant surface groups after the Al(CH3)3 precursor and O2 plasma half-cycles, respectively. At lower temperatures more -OH and C-related impurities were found to be incorporated in the Al2O3 film, but the impurity level could be reduced by prolonging the plasma exposure. The results demonstrate that -OH surface groups rule the surface chemistry of the Al2O3 process and likely that of plasma-assisted ALD of metal oxides from organometallic precursors in general.

  11. Numerical investigation on fundamental properties in capacitively-coupled methane plasmas for deposition of diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Oda, Akinori; Kousaka, Hiroyuki

    2012-10-01

    Capacitively-coupled methane (CH4) plasmas for deposition of diamond-like carbon films have been simulated using a self-consistent one-dimensional fluid model, incorporating the mass balance equations for electrons, ions, radicals and non-radicals, the electron energy balance equation, coupled with the Poisson equation. Despite of low-pressure CH4 gas condition, many positive-ion species, such as C2H4^+, CH4^+, C2H2^+, CH5^+ etc., have been found in the plasmas. The non-radical neutrals, such as C2H4, C3H8, C2H2 and C2H6, have also found with higher densities comparable to the source gas density. This result indicates that this complexity of background gas in CH4 plasmas is strongly affected to the electron energy distribution function, which is important for the determination of plasmas properties.

  12. Plasma and ion beam enhanced chemical vapour deposition of diamond and diamond-like carbon

    NASA Astrophysics Data System (ADS)

    Tang, Yongji

    WC-Co cutting tools are widely used in the machining industry. The application of diamond coatings on the surfaces of the tools would prolong the cutting lifetime and improves the manufacturing efficiency. However, direct chemical vapor deposition (CVD) of diamond coatings on WC-Co suffer from severe premature adhesion failure due to interfacial graphitization induced by the binder phase Co. In this research, a combination of hydrochloric acid (HCl) and hydrogen (H2) plasma pretreatments and a novel double interlayer of carbide forming element (CFE)/Al were developed to enhance diamond nucleation and adhesion. The results showed that both the pretreatments and interlayers were effective in forming continuous and adhesive nanocrystalline diamond coatings. The method is a promising replacement of the hazardous Murakami's regent currently used in WC-Co pretreatment with a more environmental friendly approach. Apart from coatings, diamond can be fabricated into other forms of nanostructures, such as nanotips. In this work, it was demonstrated that oriented diamond nanotip arrays can be fabricated by ion beam etching of as-grown CVD diamond. The orientation of diamond nanotips can be controlled by adjusting the direction of incident ion beam. This method overcomes the limits of other techniques in producing nanotip arrays on large areas with controlled orientation. Oriented diamond nano-tip arrays have been used to produce anisotropic frictional surface, which is successfully used in ultra-precision positioning systems. Diamond-like carbon (DLC) has many properties comparable to diamond. In this thesis, the preparation of alpha-C:H thin films by end-Hall (EH) ion source and the effects of ion energy and nitrogen doping on the microstructure and mechanical properties of the as-deposited thin films were investigated. The results have demonstrated that smooth and uniform alpha-C:H and alpha-C:H:N films with large area and reasonably high hardness and Young's modulus can be

  13. Deposition of alumina stabilized zirconia at room temperature by plasma focus device

    NASA Astrophysics Data System (ADS)

    Khan, I. A.; Rawat, R. S.; Ahmad, R.; Shahid, M. A. K.

    2014-01-01

    Nanostructured multiphase zirconium aluminium oxide (MP-ZrAlO) composite films are deposited on zirconium substrate by plasma focus device. The XRD results reveal that the crystallinity of ZrO2 and Al2O3 phases is improved for 15 focus deposition shots (FDS), while it is decreased with increasing sample angular positions. A better crystallinity of m-ZrO2 and c-ZrO2 phases is achieved at 300 °C annealing temperature, while the re-crystallization of all phases except m-ZrO2 (111) phase is observed at 600 °C annealing temperature. The strains developed in ZrO2 (111) and Al2O3 (220) planes are found to be -3.8 × 10-3 and +2.2 × 10-3, respectively, for 15 FDS ion irradiations and remained constant for higher FDS ion irradiations. The weight fraction of m-ZrO2 phase decreased from 89 to 79%, while it increased from 11 to 21% for c-ZrO2 phase with increasing FDS. The weight fraction of m-ZrO2 phase increases from 89 to 92%, while it is decreased from 11 to 8% for c-ZrO2 phase with increasing sample angular (0°-10°) positions. At 300 °C annealing temperature, the weight fractions of m-ZrO2 phase decreases from 89 to 81%, while it increased from 11 to 19% for c-ZrO2 phase. The SEM microstructures reveal that the formation of nano-grains (range from 45 nm to 100 nm), nano-strips (width ranges from 333 nm to 750 nm and length ranges from 2.5 μm to 9 μm) and nano-rods (diameter ranges from 25 nm to 50 nm) observed in different micrographs of MP-ZrAlO composite films can be attributed to increasing FDS, sample angular positions and annealing temperature. The microhardness of MP-ZrAlO composite films deposited for 25 FDS ion irradiations is found to be 9.14 ± 0.35 GPa which is approximately seven times than the microhardness of virgin zirconium.

  14. Plasma-enhanced atomic layer deposition zinc oxide for multifunctional thin film electronics

    NASA Astrophysics Data System (ADS)

    Mourey, Devin A.

    A novel, weak oxidant, plasma-enhanced atomic layer deposition (PEALD) process has been used to fabricate stable, high mobility ZnO thin film transistors (TFTs) and fast circuits on glass and polyimide substrates at 200°C. Weak oxidant PEALD provides a simple, fast deposition process which results in uniform, conformal coatings and highly crystalline, dense ZnO thin films. These films and resulting devices have been compared with those prepared by spatial atomic layer deposition (SALD) throughout the work. Both PEALD and SALD ZnO TFTs have high field-effect mobility (>20 cm 2/V·s) and devices with ALD Al2O3 passivation can have excellent bias stress stability. Temperature dependent measurements of PEALD ZnO TFTs revealed a mobility activation energy < 5 meV and can be described using a simple percolation model with a Gaussian distribution of near-conduction band barriers. Interestingly, both PEALD and SALD devices operate with mobility > 1 cm2/V·s even at temperatures < 10 K. The effects of high energy irradiation have also been investigated. Devices exposed to 1 MGy of gamma irradiation showed small threshold voltage shifts (<2 V) which were fully recoverable with short (1 min) low-temperature (200°C) anneals. ZnO TFTs exhibit a range of non-ideal behavior which has direct implications on how important parameters such as mobility and threshold voltage are quantified. For example, the accumulation-dependent mobility and contact effects can lead to significant overestimations in mobility. It is also found that self-heating plays and important role in the non-ideal behavior of oxide TFTs on low thermal conductivity substrates. In particular, the output conductance and a high current device runaway breakdown effect can be directly ascribed to self-heating. Additionally, a variety of simple ZnO circuits on glass and flexible substrates were demonstrated. A backside exposure process was used to form gate-self-aligned structures with reduced parasitic capacitance and

  15. Magnesium plasma diagnostics by heated probe and characterization of the Mg thin films deposited by thermionic vacuum arc technology

    NASA Astrophysics Data System (ADS)

    Vladoiu, Rodica; Mandes, Aurelia; Dinca Balan, Virginia; Prodan, Gabriel; Kudrna, Pavel; Tichý, Milan

    2015-06-01

    The aim of this paper is to report on magnesium plasma diagnostics and to investigate the properties of thin Mg films deposited on Si and glass substrates by using thermionic vacuum arc (TVA) technology. TVA is an original deposition method using a combination of anodic arc and powerful electron gun system (up to 600 W) for the growth of thin films from solid precursors under a vacuum of 10-6Torr. Due to the comparatively high deposition rate as well as comparatively high plasma potential—around 0.5 kV—plasma diagnostics were carried out by a heated probe that prevents layer deposition on the probe surface. The estimated value of electron density was in the order of 1.0  ×  1016m-3 and the electron temperature varied between 4  ×  104 and 1.2  ×  105 K (corresponding to two different discharge conditions). The thin Mg films were investigated using SEM images and TEM analyses provided with HR-TEM and SAED facilities. According to the SAED patterns the structure of the films can be indexed as two forms: hexagonal structure for Mg and cubic structure for MgO; the peak value of grain size distribution was 91.29 nm in diameter for Mg TVA/Si and 61.06 nm for Mg TVA/Gl.

  16. Integration of atomic layer deposited high-k dielectrics on GaSb via hydrogen plasma exposure

    SciTech Connect

    Ruppalt, Laura B. Cleveland, Erin R.; Champlain, James G.; Bennett, Brian R.; Prokes, Sharka M.

    2014-12-15

    In this letter we report the efficacy of a hydrogen plasma pretreatment for integrating atomic layer deposited (ALD) high-k dielectric stacks with device-quality p-type GaSb(001) epitaxial layers. Molecular beam eptiaxy-grown GaSb surfaces were subjected to a 30 minute H{sub 2}/Ar plasma treatment and subsequently removed to air. High-k HfO{sub 2} and Al{sub 2}O{sub 3}/HfO{sub 2} bilayer insulating films were then deposited via ALD and samples were processed into standard metal-oxide-semiconductor (MOS) capacitors. The quality of the semiconductor/dielectric interface was probed by current-voltage and variable-frequency admittance measurements. Measurement results indicate that the H{sub 2}-plamsa pretreatment leads to a low density of interface states nearly independent of the deposited dielectric material, suggesting that pre-deposition H{sub 2}-plasma exposure, coupled with ALD of high-k dielectrics, may provide an effective means for achieving high-quality GaSb MOS structures for advanced Sb-based digital and analog electronics.

  17. Effect of titanium oxide nanoparticle incorporation into nm thick coatings deposited using an atmospheric pressure plasma.

    PubMed

    Denis, Dowling P; Barry, Twomey; Gerry, Byrne

    2010-04-01

    This study reports on the use of an atmospheric plasma technique to incorporate metal oxide nanoparticles into nm thick siloxane coatings. Titanium dioxide (TiO2) particles with diameters of 30-80 nm, were mixed with a number of different siloxanes-polydimethylsiloxane, hexamethyldisiloxane and tetraethylorthosilicate (TEOS). The TiO2/TEOS mixture was found to give the most stable suspension, possibly due to the higher surface tension of TEOS compared with the other siloxanes. TiO2/TEOS mixtures with 2 to 10% by weight of the metal oxide were prepared and were then nebulised into a helium/oxygen atmospheric plasma. Polyethylene terepthalate (PET) and silicon wafer substrates were passed through this plasma using a reel-to-reel substrate manipulation system. SEM combined with EDX was used to examine the distribution of the metal oxide particles in the resultant coatings. The TEOS coating thickness without TiO2 addition was 9 nm. The composite coating consisted of a relatively homogeneous distribution of small agglomerates of the TiO2 nanoparticles in TEOS. A linear increase in the titanium surface concentration was observed with increase in the quantity of TiO2 added into the siloxane precursor. The chemical functionality of the siloxane coating was examined using FTIR spectroscopy and no significant spectrum differences was observed with the incorporation of the different concentrations of TiO2 into the polymer. There were also no changes observed in coating surface energy with TiO2 incorporation. Coating morphology was examined using optical profilometry and surface roughness (Ra) values increased from typical values of 0.8 nm for the TEOS coating to 4.1 nm for the TiO2/TEOS coating. The adhesion of the deposited coatings was compared using fragmentation tests. These were carried out through uniaxial tensile loading. The coating cracking pattern after applied strain of 20% was not observed to change significantly with the addition of TiO2 into the siloxane. PMID

  18. Characterization of plasma-enhanced atomic layer deposition of Al{sub 2}O{sub 3} using dimethylaluminum isopropoxide

    SciTech Connect

    Yang, Jialing; Eller, Brianna S.; Nemanich, Robert J.; Kaur, Manpuneet

    2014-03-15

    In this research, Al{sub 2}O{sub 3} films were grown by remote plasma-enhanced atomic layer deposition using a nonpyrophoric precursor, dimethylaluminum isopropoxide (DMAI), and oxygen plasma. After optimization, the growth rate was determined to be ∼1.5 Å/cycle within a growth window of 25–220 °C; the higher growth rate than reported for thermal atomic layer deposition was ascribed to the higher reactivity of the plasma species compared with H{sub 2}O and the adsorption of active oxygen at the surface, which was residual from the oxygen plasma exposure. Both effects enhance DMAI chemisorption and increase the saturation density. In addition, a longer oxygen plasma time was required at room temperature to complete the reaction and decrease the carbon contamination below the detection limit of x-ray photoemission spectroscopy. The properties of the subsequent Al{sub 2}O{sub 3} films were measured for different temperatures. When deposited at 25 °C and 200 °C, the Al{sub 2}O{sub 3} films demonstrated a single Al-O bonding state as measured by x-ray photoemission spectroscopy, a similar band gap of 6.8±0.2 eV as determined by energy loss spectroscopy, a similar index of refraction of 1.62±0.02 as determined by spectroscopic ellipsometry, and uniform growth with a similar surface roughness before and after growth as confirmed by atomic force microscopy. However, the room temperature deposited Al{sub 2}O{sub 3} films had a lower mass density (2.7 g/cm{sup 3} compared with 3.0 g/cm{sup 3}) and a higher atomic ratio of O to Al (2.1 compared with 1.6) as indicated by x-ray reflectivity and Rutherford backscattering spectroscopy, respectively.

  19. Low temperature SiNx:H films deposited by inductively coupled plasma for solar cell applications

    NASA Astrophysics Data System (ADS)

    Zhou, H. P.; Wei, D. Y.; Xu, L. X.; Guo, Y. N.; Xiao, S. Q.; Huang, S. Y.; Xu, S.

    2013-01-01

    Amorphous hydrogenated silicon nitride thin films with different chemical compositions (SiNx:H) have been synthesized by using low frequency inductively coupled plasma of Si + N2 + H2 at a low temperature of 100 °C. The bonding configurations, bond density, hydrogen content, and chemical composition, as well as the refractive index are intensively investigated by a variety of characterization tools. Silicon nitride based antireflection layer on alkaline-textured silicon surface reduces the reflectivity to about 4%. As-deposited silicon nitride films exhibit an excellent passivation effect on p- and n-type Si. The surface recombination velocity is reduced to 36 cm/s on n-type silicon with resistivity of 2-3 Ω cm. The passivation effect originates from the H-related chemical passivation and fixed charge related field passivation. The growth mechanism of SiNx:H from the precursor gas of H2 diluted mixture of silane and nitrogen is also discussed.

  20. Surface modification of biomaterials using plasma immersion ion implantation and deposition

    PubMed Central

    Lu, Tao; Qiao, Yuqin; Liu, Xuanyong

    2012-01-01

    Although remarkable progress has been made on biomaterial research, the ideal biomaterial that satisfies all the technical requirements and biological functions is not available up to now. Surface modification seems to be a more economic and efficient way to adjust existing conventional biomaterials to meet the current and ever-evolving clinical needs. From an industrial perspective, plasma immersion ion implantation and deposition (PIII&D) is an attractive method for biomaterials owing to its capability of treating objects with irregular shapes, as well as the control of coating composition. It is well acknowledged that the physico-chemical characteristics of biomaterials are the decisive factors greatly affecting the biological responses of biomaterials including bioactivity, haemocompatibility and antibacterial activity. Here, we mainly review the recent advances in surface modification of biomaterials via PIII&D technology, especially titanium alloys and polymers used for orthopaedic, dental and cardiovascular implants. Moreover, the variations of biological performances depending on the physico-chemical properties of modified biomaterials will be discussed. PMID:23741609

  1. Molecular plasma deposition: biologically inspired nanohydroxyapatite coatings on anodized nanotubular titanium for improving osteoblast density

    PubMed Central

    Balasundaram, Ganesan; Storey, Daniel M; Webster, Thomas J

    2015-01-01

    In order to begin to prepare a novel orthopedic implant that mimics the natural bone environment, the objective of this in vitro study was to synthesize nanocrystalline hydroxyapatite (NHA) and coat it on titanium (Ti) using molecular plasma deposition (MPD). NHA was synthesized through a wet chemical process followed by a hydrothermal treatment. NHA and micron sized hydroxyapatite (MHA) were prepared by processing NHA coatings at 500°C and 900°C, respectively. The coatings were characterized before and after sintering using scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results revealed that the post-MPD heat treatment of up to 500°C effectively restored the structural and topographical integrity of NHA. In order to determine the in vitro biological responses of the MPD-coated surfaces, the attachment and spreading of osteoblasts (bone-forming cells) on the uncoated, NHA-coated, and MHA-coated anodized Ti were investigated. Most importantly, the NHA-coated substrates supported a larger number of adherent cells than the MHA-coated and uncoated substrates. The morphology of these cells was assessed by scanning electron microscopy and the observed shapes were different for each substrate type. The present results are the first reports using MPD in the framework of hydroxyapatite coatings on Ti to enhance osteoblast responses and encourage further studies on MPD-based hydroxyapatite coatings on Ti for improved orthopedic applications. PMID:25609958

  2. Microstructural modifications induced by rapid thermal annealing in plasma deposited SiOxNyHz films

    NASA Astrophysics Data System (ADS)

    del Prado, A.; San Andrés, E.; Mártil, I.; González-Díaz, G.; Bravo, D.; López, F. J.; Fernández, M.; Martínez, F. L.

    2003-07-01

    The effect of rapid thermal annealing (RTA) processes on the structural properties of SiOxNyHz films was investigated. The samples were deposited by the electron cyclotron resonance plasma method, using SiH4, O2 and N2 as precursor gases. For SiOxNyHz films with composition close to that of SiO2, which have a very low H content, RTA induces thermal relaxation of the lattice and improvement of the structural order. For films of intermediate composition and of compositions close to SiNyHz, the main effect of RTA is the release of H at high temperatures (T>700 °C). This H release is more significant in films containing both Si-H and N-H bonds, due to cooperative reactions between both kinds of bonds. In these films the degradation of structural order associated to H release prevails over thermal relaxation, while in those films with only N-H bonds, thermal relaxation predominates. For annealing temperatures in the 500-700 °C range, the passivation of dangling bonds by the nonbonded H in the films and the transition from the paramagnetic state to the diamagnetic state of the K center result in a decrease of the density of paramagnetic defects. The H release observed at high annealing temperatures is accompanied by an increase of density of paramagnetic defects.

  3. Cell proliferation on modified DLC thin films prepared by plasma enhanced chemical vapor deposition.

    PubMed

    Stoica, Adrian; Manakhov, Anton; Polčák, Josef; Ondračka, Pavel; Buršíková, Vilma; Zajíčková, Renata; Medalová, Jiřina; Zajíčková, Lenka

    2015-01-01

    Recently, diamondlike carbon (DLC) thin films have gained interest for biological applications, such as hip and dental prostheses or heart valves and coronary stents, thanks to their high strength and stability. However, the biocompatibility of the DLC is still questionable due to its low wettability and possible mechanical failure (delamination). In this work, DLC:N:O and DLC: SiOx thin films were comparatively investigated with respect to cell proliferation. Thin DLC films with an addition of N, O, and Si were prepared by plasma enhanced CVD from mixtures of methane, hydrogen, and hexamethyldisiloxane. The films were optically characterized by infrared spectroscopy and ellipsometry in UV-visible spectrum. The thickness and the optical properties were obtained from the ellipsometric measurements. Atomic composition of the films was determined by Rutherford backscattering spectroscopy combined with elastic recoil detection analysis and by x-ray photoelectron spectroscopy. The mechanical properties of the films were studied by depth sensing indentation technique. The number of cells that proliferate on the surface of the prepared DLC films and on control culture dishes were compared and correlated with the properties of as-deposited and aged films. The authors found that the level of cell proliferation on the coated dishes was high, comparable to the untreated (control) samples. The prepared DLC films were stable and no decrease of the biocompatibility was observed for the samples aged at ambient conditions. PMID:25967153

  4. Cytotoxicity of Boron-Doped Nanocrystalline Diamond Films Prepared by Microwave Plasma Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Liu, Dan; Gou, Li; Ran, Junguo; Zhu, Hong; Zhang, Xiang

    2015-07-01

    Boron-doped nanocrystalline diamond (NCD) exhibits extraordinary mechanical properties and chemical stability, making it highly suitable for biomedical applications. For implant materials, the impact of boron-doped NCD films on the character of cell growth (i.e., adhesion, proliferation) is very important. Boron-doped NCD films with resistivity of 10-2 Ω·cm were grown on Si substrates by the microwave plasma chemical vapor deposition (MPCVD) process with H2 bubbled B2O3. The crystal structure, diamond character, surface morphology, and surface roughness of the boron-doped NCD films were analyzed using different characterization methods, such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The contact potential difference and possible boron distribution within the film were studied with a scanning kelvin force microscope (SKFM). The cytotoxicity of films was studied by in vitro tests, including fluorescence microscopy, SEM and MTT assay. Results indicated that the surface roughness value of NCD films was 56.6 nm and boron was probably accumulated at the boundaries between diamond agglomerates. MG-63 cells adhered well and exhibited a significant growth on the surface of films, suggesting that the boron-doped NCD films were non-toxic to cells. supported by the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (University of Electronic Science and Technology of China) (No. KFJJ201313)

  5. Annealing of chromium oxycarbide coatings deposited by plasma immersion ion processing (PIIP) for aluminum die casting

    NASA Astrophysics Data System (ADS)

    Peters, A. M.; He, X. M.; Trkula, M.; Nastasi, M.

    2001-04-01

    Chromium oxycarbide coatings have been investigated for use as non-wetting coatings for aluminum die casting. This paper examines Cr-C-O coating stability and non-wetability at elevated temperatures for extended periods. Coatings were deposited onto 304 stainless steel from chromium carbonyl [Cr(CO) 6] by plasma immersion ion processing. The coatings were annealed in air at an aluminum die casting temperature of 700°C up to 8 h. Coatings were analyzed using resonant ion backscattering spectroscopy, nanoindentation and pin-on-disk tribometry. Molten aluminum was used to determine coating wetting and contact angle. Results indicate that the surface oxide layer reaches a maximum thickness of 900 nm. Oxygen concentrations in the coatings increased from 24% to 34%, while the surface concentration rose to almost 45%. Hardness values ranged from 22.1 to 6.7 GPa, wear coefficients ranged from 21 to 8×10 -6 mm3/ Nm and contact angles ranged from 156° to 127°.

  6. Thermal conductivities of nanostructured magnesium oxide coatings deposited on magnesium alloys by plasma electrolytic oxidation.

    PubMed

    Shen, Xinwei; Nie, Xueyuan; Hu, Henry

    2014-10-01

    The resistances of magnesium alloys to wear, friction and corrosion can be effectively improved by depositing coatings on their surfaces. However, the coatings can also reduce the heat transfer from the coated components to the surroundings (e.g., coated cylinder bores for internal combustion of engine blocks). In this paper, nanostructured magnesium oxides were produced by plasma electrolytic oxidation (PEO) process on the magnesium alloy AJ62 under different current densities. The guarded comparative heat flow method was adopted to measure the thermal conductivities of such coatings which possess gradient nanoscale grain sizes. The aim of the paper is to explore how the current density in the PEO process affects the thermal conductivity of the nanostructured magnesium coatings. The experimental results show that, as the current density rises from 4 to 20 A/mm2, the thermal conductivity has a slight increase from 0.94 to 1.21 W/m x K, which is significantly smaller than that of the corresponding bulk magnesium oxide materials (29.4 W/m x K). This mostly attributed to the variation of the nanoscale grain sizes of the PEO coatings. PMID:25942897

  7. Heteroepitaxial growth of wafer scale highly oriented graphene using inductively coupled plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Gao, Libo; Xu, Hai; Li, Linjun; Yang, Yang; Fu, Qiang; Bao, Xinhe; Loh, Kian Ping

    2016-06-01

    The chemical vapor deposition (CVD) of graphene on Cu has attracted much attention because of its industrial scalability. Herein, we report inductively coupled plasma-assisted CVD of epitaxially grown graphene on (111)-textured Cu film alloyed with a small amount of Ni, where large area high quality graphene film can be grown in less than 5 min at 800 °C, thus affording industrial scalability. The epitaxially grown graphene films on (111)-textured Cu contain grains which are predominantly aligned with the Cu lattice and about 10% of 30°-rotated grains (anti-grains). Such graphene films are exclusively monolayer and possess good electrical conductivity, high carrier mobility, and room temperature quantum Hall effect. Magnetoresistance measurements reveal that the reduction of the grain sizes from 150 nm to 50 nm produce increasing Anderson localization and the appearance of a transport gap. Owing to the presence of grain boundaries in these anti-grains, epitaxially grown graphene films possess n-type characteristics and exhibit ultra-high sensitivity to adsorbates.

  8. Features of silicon-containing coatings deposition from ablation plasma formed by a powerful ion beam

    NASA Astrophysics Data System (ADS)

    Sazonov, R.; Kholodnaya, G.; Ponomarev, D.; Remnev, G.; Khailov, I.

    2014-11-01

    This paper presents the research of features of silicon-containing coatings deposition from ablation plasma, which is formed by a powerful ion beam at the influence on a microsized pressed powder of SiO2. Experimental research have been conducted with a laboratory setup based on a TEMP-4M pulsed ion accelerator in a double-pulse forming mode; the first is negative (300-500 ns, 100-150 kV), and the second is positive (150 ns, 250-300 kV). A beam composition: C+ ions (60-70 %) and protons, the ion current density on the target is 25±5 A/cm2. An electron self-magnetically insulated diode has been used to generate the ion beam in the TEMP-4M accelerator. The properties of obtained silicon-containing films have been analyzed with the help of IR spectroscopy. A surface structure has been studied by the method of scanning electron microscopy.

  9. Co-deposition of titanium and iron nitrides on SS-321 by using plasma focus

    NASA Astrophysics Data System (ADS)

    Ahmad, R.; Hassan, M.; Murtaza, G.; Akhter, J. I.; Qayyum, A.; Waheed, A.; Zakaullah, M.

    2006-02-01

    This article reports the co-deposition process of TiN0.9 and (Fe,Cr)(2)N compounds on SS-321 substrate using a 2.3 kJ dense plasma focus device operated with N-2 discharges. X-ray diffraction analysis is performed to investigate the ion-induced changes in the near surface structure of the SS-321. Scanning electron microscopy with the energy dispersive X-ray spectroscopy is carried out to analyse the surface morphology and the elemental composition of the nitrided samples. The results reveal that at the low fluence of ion bombardment, a non-stoichiometric tertiary phase (Fe,Cr)(x)N is developed, which transforms into a stable stoichiometric compound (Fe,Cr)(2)N by increasing the ion flux. Some CrN precipitates are also observed because of the thermal effect produced by the bombardment of energetic ion beam. Vickers micro-hardness values are increased more than twice for typical ion nitrided samples.

  10. Thermal Conductivity of Nanocrystalline Silicon Prepared by Plasma-Enhanced Chemical-Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Jugdersuren, Battogtokh; Liu, Xiao; Kearney, Brian; Queen, Daniel; Metcalf, Thomas; Culbertson, James; Chervin, Christopher; Katz, Michael; Stroud, Rhonda

    Nanocrystallization by ball milling has been used successfully to reduce the thermal conductivity of silicon-germanium alloys (SiGe) and turn them into useful thermoelectric materials at a temperature of a few hundred degrees C. Currently the smallest grain sizes in nanocrystalline SiGe are in the 10 nm range. Germanium is added to scatter short wavelength phonons by impurity scattering. In this work, we report a record low thermal conductivity in nanocrystalline silicon prepared by plasma-enhanced chemical-vapor deposition. By varying hydrogen to silane ratio, we can vary the average grain sizes from greater than 10 nm down to 3 nm, as determined by both the high resolution transmission electron microscopy and X-ray diffraction. The values of thermal conductivity, as measured by the 3 ω technique, can be correspondingly modulated from that of ball-milled nanocrystalline SiGe to a record low level of 0.3 W/mK at room temperature. This low thermal conductivity is only about 1/3 of the minimum thermal conductivity limit of silicon. Possible causes of such a large reduction are discussed. Work supported by the Office of Naval Research.

  11. Nanostructured TaxC interlayer synthesized via double glow plasma surface alloying process for diamond deposition on cemented carbide

    NASA Astrophysics Data System (ADS)

    Rong, Wolong; Hei, Hongjun; Zhong, Qiang; Shen, Yanyan; Liu, Xiaoping; Wang, Xin; Zhou, Bing; He, Zhiyong; Yu, Shengwang

    2015-12-01

    The aim in this work was to improve the adhesion of diamond coating with pre-deposition of a TaxC interlayer on cemented carbide (WC-Co) substrate by double glow plasma surface alloying technique. The following deposition of diamond coating on the interlayer was performed in a microwave plasma chemical vapor deposition (MPCVD) reactor. TaxC interlayer with an inner diffusion layer and an outer deposition layer was composed of Ta2C and TaC nanocrystalline, and it exhibited a special compact surface morphology formed of flower-shaped pits. As the gradual element distributions existed in the diffusion layer, the interlayer displayed a superior adherence to the substrate with significantly enhanced surface microhardness to the original substrate. After CVD process, the preferred orientation of TaC changed from (2 2 2) to (2 0 0) plane, and a uniform and tense diamond coating with adhesion referred to class HF 2 at least (Verein Deutscher Ingenieure 3198 norm) was obtained on the interlayered substrate. It indicated that the diffusion of Co was effectively inhibited by the formation of TaxC diffusion-deposition interlayer. The TaxC interlayer is most likely to improve the performance of diamond coatings used in cutting tools.

  12. 2D fluid model analysis for the effect of 3D gas flow on a capacitively coupled plasma deposition reactor

    NASA Astrophysics Data System (ADS)

    Kim, Ho Jun; Lee, Hae June

    2016-06-01

    The wide applicability of capacitively coupled plasma (CCP) deposition has increased the interest in developing comprehensive numerical models, but CCP imposes a tremendous computational cost when conducting a transient analysis in a three-dimensional (3D) model which reflects the real geometry of reactors. In particular, the detailed flow features of reactive gases induced by 3D geometric effects need to be considered for the precise calculation of radical distribution of reactive species. Thus, an alternative inclusive method for the numerical simulation of CCP deposition is proposed to simulate a two-dimensional (2D) CCP model based on the 3D gas flow results by simulating flow, temperature, and species fields in a 3D space at first without calculating the plasma chemistry. A numerical study of a cylindrical showerhead-electrode CCP reactor was conducted for particular cases of SiH4/NH3/N2/He gas mixture to deposit a hydrogenated silicon nitride (SiN x H y ) film. The proposed methodology produces numerical results for a 300 mm wafer deposition reactor which agree very well with the deposition rate profile measured experimentally along the wafer radius.

  13. Low temperature deposition of Ga{sub 2}O{sub 3} thin films using trimethylgallium and oxygen plasma

    SciTech Connect

    Donmez, Inci; Ozgit-Akgun, Cagla; Biyikli, Necmi

    2013-01-15

    Gallium oxide (Ga{sub 2}O{sub 3}) thin films were deposited by plasma-enhanced atomic layer deposition (ALD) using trimethylgallium as the gallium precursor and oxygen plasma as the oxidant. A wide ALD temperature window was observed from 100 to 400 Degree-Sign C, where deposition rate was constant at {approx}0.53 A/cycle. X-ray photoelectron spectroscopy survey scans indicated the presence of gallium, oxygen, and carbon elements with concentrations of {approx}36, {approx}51.8, and {approx}12.2 at. %, respectively. As-deposited films were amorphous; upon annealing at 900 Degree-Sign C under N{sub 2} atmosphere for 30 min, polycrystalline {beta}-Ga{sub 2}O{sub 3} phase with a monoclinic crystal structure was obtained. Refractive index and root mean square roughness of the annealed Ga{sub 2}O{sub 3} film were higher than those of the as-deposited due to crystallization.

  14. Microwave processing of epoxy resins and synthesis of carbon nanotubes by microwave plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zong, Liming

    Microwave processing of advanced materials has been studied as an attractive alternative to conventional thermal processing. In this dissertation, work was preformed in four sections. The first section is a review on research status of microwave processing of polymer materials. The second section is investigation of the microwave curing kinetics of epoxy resins. The curing of diglycidyl ether of bisphenol A (DGEBA) and 3, 3'-diaminodiphenyl sulfone (DDS) system under microwave radiation at 145 °C was governed by an autocatalyzed reaction mechanism. A kinetic model was used to describe the curing progress. The third section is a study on dielectric properties of four reacting epoxy resins over a temperature range at 2.45 GHz. The epoxy resin was DGEBA. The four curing agents were DDS, Jeffamine D-230, m-phenylenediamine, and diethyltoluenediamine. The mixtures of DGEBA and the four curing agents were stoichiometric. The four reacting systems were heated under microwave irradiation to certain cure temperatures. Measurements of temperature and dielectric properties were made during free convective cooling of the samples. The cooled samples were analyzed with a Differential Scanning Calorimeter to determine the extents of cure. The Davidson-Cole model can be used to describe the dielectric data. A simplified Davidson-Cole expression was proposed to calculate the parameters in the Davidson-Cole model and describe the dielectric properties of the DGEBA/DDS system and part of the dielectric data of the other three systems. A single relaxation model was used with the Arrhenius expression for temperature dependence to model the results. The evolution of all parameters in the models during cure was related to the decreasing number of the epoxy and amine groups in the reactants and the increasing viscosity of the reacting systems. The last section is synthesis of carbon nanotubes (CNTs) on silicon substrate by microwave plasma chemical vapor deposition of a gas mixture of

  15. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Podhorodecki, A.; Zatryb, G.; Misiewicz, J.; Wojcik, J.; Wilson, P. R. J.; Mascher, P.

    2012-11-01

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature.

  16. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition.

    PubMed

    Podhorodecki, A; Zatryb, G; Misiewicz, J; Wojcik, J; Wilson, P R J; Mascher, P

    2012-11-30

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature. PMID:23110801

  17. Structure and gas-barrier properties of amorphous hydrogenated carbon films deposited on inner walls of cylindrical polyethylene terephthalate by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Li, Jing; Gong, Chunzhi; Tian, Xiubo; Yang, Shiqin; Fu, Ricky K. Y.; Chu, Paul K.

    2009-01-01

    The influence of radio-frequency (RF) power on the structure and gas permeation through amorphous hydrogenated carbon films deposited on cylindrical polyethylene terephthalate (PET) samples is investigated. The results show that a higher radio-frequency power leads to a smaller sp 3/sp 2 value but produces fewer defects with smaller size. The permeability of PET samples decreases significantly after a-C:H deposition and the RF only exerts a small influence. However, the coating uniformity, color, and wettability of the surface are affected by the RF power. A higher RF power results in to better uniformity and it may be attributed to the combination of the high-density plasma and sample heating.

  18. Comparison of gate dielectric plasma damage from plasma-enhanced atomic layer deposited and magnetron sputtered TiN metal gates

    SciTech Connect

    Brennan, Christopher J.; Neumann, Christopher M.; Vitale, Steven A.

    2015-07-28

    Fully depleted silicon-on-insulator transistors were fabricated using two different metal gate deposition mechanisms to compare plasma damage effects on gate oxide quality. Devices fabricated with both plasma-enhanced atomic-layer-deposited (PE-ALD) TiN gates and magnetron plasma sputtered TiN gates showed very good electrostatics and short-channel characteristics. However, the gate oxide quality was markedly better for PE-ALD TiN. A significant reduction in interface state density was inferred from capacitance-voltage measurements as well as a 1200× reduction in gate leakage current. A high-power magnetron plasma source produces a much higher energetic ion and vacuum ultra-violet (VUV) photon flux to the wafer compared to a low-power inductively coupled PE-ALD source. The ion and VUV photons produce defect states in the bulk of the gate oxide as well as at the oxide-silicon interface, causing higher leakage and potential reliability degradation.

  19. Comparison of gate dielectric plasma damage from plasma-enhanced atomic layer deposited and magnetron sputtered TiN metal gates

    NASA Astrophysics Data System (ADS)

    Brennan, Christopher J.; Neumann, Christopher M.; Vitale, Steven A.

    2015-07-01

    Fully depleted silicon-on-insulator transistors were fabricated using two different metal gate deposition mechanisms to compare plasma damage effects on gate oxide quality. Devices fabricated with both plasma-enhanced atomic-layer-deposited (PE-ALD) TiN gates and magnetron plasma sputtered TiN gates showed very good electrostatics and short-channel characteristics. However, the gate oxide quality was markedly better for PE-ALD TiN. A significant reduction in interface state density was inferred from capacitance-voltage measurements as well as a 1200× reduction in gate leakage current. A high-power magnetron plasma source produces a much higher energetic ion and vacuum ultra-violet (VUV) photon flux to the wafer compared to a low-power inductively coupled PE-ALD source. The ion and VUV photons produce defect states in the bulk of the gate oxide as well as at the oxide-silicon interface, causing higher leakage and potential reliability degradation.

  20. New method of plasma immersion ion implantation and also deposition of industrial components using tubular fixture and plasma generated inside the tube by high voltage pulses

    NASA Astrophysics Data System (ADS)

    Ueda, Mario; Silva, Ataide Ribeiro da; Pillaca, Elver J. D. M.; Mariano, Samantha F. M.; Oliveira, Rogério de Moraes; Rossi, José Osvaldo; Lepienski, Carlos Mauricio; Pichon, Luc

    2016-01-01

    A new method of Plasma Immersion Ion Implantation (PIII) and deposition (PIII and D) for treating industrial components in the batch mode has been developed. A metal tubular fixture is used to allocate the components inside, around, and along the tube, exposing only the parts of each component that are to be ion implanted to the plasma. Hollow cathode-like plasma is generated only inside the tube filled with the desired gas, by applying high negative voltage pulses to the hollow cylindrical fixture which is insulated from the vacuum chamber walls. This is a very convenient method of batch processing of industrial parts by ion implantation, in which a large number of small to medium sized components can be treated by PIII and PIII and D, very quickly, efficiently, and also at low cost.