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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 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.

  13. 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.

  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, 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.

  18. 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.

  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. 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.

  10. 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}

  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. 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.

  6. 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.

  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. 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.

  9. 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.

  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. 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.

  3. 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.

  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. 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.

  7. 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.

  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. 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.

  14. 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.

  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. 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.

  20. 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.

  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. 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

  5. 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.

  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, 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.

  13. 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.

  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. 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

  17. 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.

  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. 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.

  4. 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.

  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. 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.

  11. 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.

  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. 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.

  5. 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.

  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. 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.

  9. 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.

  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. 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.

  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. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  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. 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.

  7. 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.

  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. 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.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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

  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. 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.

  19. 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.

  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. 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.

  2. 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.

  3. 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.

  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. 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.

  14. 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.

  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

    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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.