... were grown on (0 0 0 1) (C-plane) and (1 1 2 0) (A-plane) oriented sapphire substrates by the reduction of sol-gel derived vanadium oxide films. ...
DTIC Science & Technology
The fabrication of a blue m-plane GaInN light emitting diode (LED) grown on an m-plane GaN layer grown on a 3-in. patterned sapphire substrate is reported. The output power of the LED was approximately 3 mW at the wavelength of 461 nm, a driving current of 20 mA, and a forward voltage of 3.5 V. This is the first report of nonpolar or semipolar blue LEDs ...
NASA Astrophysics Data System (ADS)
ZnO nanowires were fabricated on c-plane (0 0 0 1), a-plane (1 1 2� 0) sapphire, and boron doped p-type (1 0 0) Si substrates in vacuum furnace by simple physical vapor deposition. Room temperature photoluminescence spectra of the nanowires show the near band-edge emission and the deep-level green light emission. The ZnO nanowires ...
This paper reports the growth by molecular beam epitaxy of AlN and GaN thin films on R-plane sapphire substrates. Contrary to previous findings that GaN grows with its (1120) A-plane parallel to the (1102) R-plane of sapphire, our results indicate that the crystallographic orientation of the III-nitride films is ...
Energy Citations Database
... Title : Electroluminescent Device in Silicon on Sapphire. ... Crystalline silicon is formed on the sapphire substrate and patterned into a mesa. ...
Epitaxial growth of non-polar (11bar 20);{Zno} thin films (a-plane ZnO) on {(1bar 102)} sapphire (r-plane sapphire) were successfully implemented through metal organic chemical vapor deposition (MOCVD) and radio-frequency sputtering, respectively. For ZnO film deposited by sputtering, the growth temperature and the flow ratios of ...
The electrical properties of Mg-doped a-plane Ga1-xInxN (0sapphire substrates by metalorganic vapor phase epitaxy were systematically investigated. The activation energy of Mg acceptors in a-plane Ga0.83In0.17N was as small as 48 ...
GaN-based flip-chip LEDs (FC-LEDs) with geometric sapphire shaping structure were fabricated. The sapphire shaping structure was formed on the bottom side of the sapphire substrate by the chemical wet etching technique for the purpose of light extraction. The crystallography-etched facets were (1 0 1 0) M-plane, (1 ...
The influence of the carrier gas used during the thermal cleaning of r-plane sapphire substrates and the subsequent first AlN layer growth at 1050 �C on two-step growth of a-plane AlN layers by hydride vapor phase epitaxy (HVPE) was investigated. When hydrogen (H2) was used as the carrier gas, the decomposition of r-plane sapphire ...
Non-polar a-plane (112�0) GaN thin films were grown on r-plane (11�02) sapphire substrates by metal-organic chemical vapor deposition. In order to obtain a-plane GaN films with better crystal quality and surface morphology, detailed comparisons between different growth conditions were investigated. The results ...
A high-quality a-plane GaN layer with a pit-free, mirror-like surface was grown on a hemispherical patterned r-plane sapphire substrate (PSS) by metal--organic chemical vapor deposition. The use of the r-plane PSS reduced the density of defects such as basal plane staking faults and threading dislocations of the a-plane GaN. The ...
We report on orange a-plane light-emitting diodes (LEDs) with InGaN single quantum well (SQW) grown on r-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). The peak wavelength and the full-width at half maximum (FWHM) at a drive current of 20mA were 612.2 nm and 72 nm, respectively. The device demonstrated a ...
PubMed
We report blue-purple pn-junction light-emitting diodes (LEDs) with a-plane GaN-InGaN multiple quantum well active region. The LEDs were grown over r-plane sapphire substrates. Our study has shown the low pump intensity photoluminencence and electroluminescence to be dominated by emission from the band-tail states which then saturates rapidly giving rise ...
High-quality epitaxial Nb thin films (thickness, 2000 A), characterized by flat and clean surfaces, high superconducting critical temperature (max.T/sub c/, 9.44 K), large resistivity ratio (RR, resistivity at room temperature divided by resistivity at 10 K, max.RR, 44), and very small quantities of grains of different orientation, have been formed on sapphire-A and ...
Nonpolar a-plane (1 bar 2 0) GaN films have been grown on r-plane (1 bar 1 02) sapphire by metal-organic chemical vapor deposition (MOCVD) under different growth pressures. The as-grown films are investigated by optical microscopy, high-resolution X-ray diffraction (HRXRD) and Raman scattering. As growth pressure rises from 100 mbar to 400 mbar, the ...
... The single crystal sapphire substrate is an excellent medium for ... ARSENIDES, GATES(CIRCUITS), SINGLE CRYSTALS, SUBSTRATES, SAPPHIRE ...
The stress and wafer bending of (1120) a-plane GaN layers of different thicknesses grown on (1102) r-plane sapphire substrates by hydride vapor phase epitaxy were studied by high-resolution x-ray diffraction and photoluminescence and photoreflectance spectroscopies. The layers are found to be under compression in the growth plane and ...
We report on the properties of nonpolar a-plane (Zn,Mg)O/ZnO quantum wells (QW) grown by molecular beam epitaxy on r plane sapphire and a plane ZnO substrates. For the QWs grown on sapphire, the anisotropy of the lattice parameters of the (Zn,Mg)O barrier gives rise to an unusual in-plane strain state in the ZnO ...
Magnetic properties of Co2MnGe thin films of different thicknesses (13, 34, 55, 83, 100, and 200 nm), grown by rf sputtering at 400 �C on single crystal sapphire substrates, were studied using vibrating sample magnetometry and conventional or microstrip line ferromagnetic resonance. Their behavior is described assuming a magnetic energy density showing ...
The need to improve superconducting thin film coatings for radio frequency (SRF) cavities used in linear accelerators has inspired recent niobium thin film research. To better understand the SRF properties in thin film niobium, correlated studies of structure, surface morphology and SRF performance are examined. Recent work on epitaxial growth of niobium on insulating ceramic ...
1 Orientation Relationships of Copper Crystals on CPlane Sapphire Stefano Curiotto1 , Harry Chien to form isolated copper crystals. The substrates consisted of singleside epipolished sapphire wafers, 5 directions of the copper crystals that are normal to the sapphire substrate, as this also ...
E-print Network
creation of single crystal Al2O3 islands on the sapphire substrates. `AGOG' is an acronym for the unique sapphire single crystal to consume the oxide layer [shown in figure 2(b)]. Electron backscatter diffraction at 4500 C, and (b) single crystal formation after 12000 C anneal. Sapphire ...
structures in r-plane single crystal sapphire. ... thinning a sapphire substrate from 25?m to 7?m in thickness suspended with Kevlar fibers for thermal ...
NASA Website
The objective of this research program was to improve the surface finish of rough ground sapphire substrates by optimizing the pretreatment, the chemical polishing agent, and the polishing cycle. The optimum conditions for chemically polishing sapphire we...
National Technical Information Service (NTIS)
Raman and emission properties of a nonpolar a-plane InGaN/GaN blue-green light emitting diode (LED) on an r-sapphire substrate are investigated and compared with a conventional c-plane blue-green LED. The output power of the a-plane LED was 1.4 mW at 20 mA. The c-plane LED has higher EQE, but it reaches the maximum at a lower forward ...
Nonpolar (11\\bar{2}0) a-plane InGaN/GaN single quantum well (SQW) structure has been grown using a multi buffer layer on a (1\\bar{1}02) r-plane sapphire substrate. The effects on the lattice constants of the a-plane GaN template caused by reactor pressure and V/III ratio of the first buffer layer were studied to improve the crystal ...
Non-polar a-plane (11bar 20) GaN films have been grown on r-plane (1bar 102) sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction ...
... Pagination or Media Count : 4. Abstract : A monocrystalline germanium film is grown on a sapphire substrate with a (I 102) orientation. ...
Page 1. Gallium nitride light emitter on a patterned sapphire substrate for improved defectivity and light extraction efficiency ...
... Title : Gallium Nitride Light Emitter on a Patterned Sapphire Substrate for Improved Defectivity and Light Extraction Efficiency. ...
... Abstract : ALUMINUM NITRIDE FILMS ON R-PLANE SAPPHIRE HAVE BEEN ... FACTORS INHERENT IN THE SUBSTRATE THAT EFFECT ...
In the growth of nonpolar (1120) a-plane GaN on r-plane (1102) sapphire by plasma-assisted molecular beam epitaxy, misoriented crystallites are observed close to the substrate. They have average diameter {approx}10 nm and are oriented with the (0001){sub GaN} plane approximately parallel to the (2113){sub sapph.} plane and [0110]{sub ...
Nonpolar a-plane GaN epilayers are grown on several r-plane sapphire substrates by metal organic chemical vapour deposition using different nucleation layers: (A) a GaN nucleation layer deposited at low temperature (LT); (B) an AlN nucleation layer deposited at high temperature; or (C) an LT thin AlN nucleation layer with an AlN layer ...
The semiconducting properties of 0.5 micrometers silicon films heteroepitaxially deposited on sapphire and spinel substrates are strongly influenced by the chemical and physical nature of the silicon-substrate interface. The nature of the interface is in ...
Piezoelectric zinc oxide (ZnO) and its ternary alloy magnesium zinc oxide (Mg{sub x}Zn{sub 1-x}O) films are deposited on r-plane (0112) sapphire (Al{sub 2}O{sub 3}) substrates using the hybrid deposition technology by combining metal-organic chemical vapor deposition (MOCVD) and sputtering. An ultra-thin ZnO buffer is first grown on r-Al{sub 2}O{sub 3} by ...
The patent application uses a sapphire (Al203) substrate base upon which is grown an array of ultraviolet light emitting diodes. The sapphire substrate is sputtered with aluminum nitride (AlN) at the points at which the diodes are to be grown. The sputter...
Growth and electrical characteristics of Mg-doped p-type nonpolar (1120) a-plane GaN films, grown on (1102) r-plane sapphire substrates via metalorganic chemical vapor deposition, were investigated as a function of growth rate, the ammonia to trimethylgallium flow ratio (V/III ratio), and the growth temperature. The electrical ...
It was critical to optimize V/III ratio for growing high quality GaN epilayers, because a suitable V/III ratio can promote the two-dimensional growth mode and decrease the crystalline anisotropy. In this paper, in order to investigate the influence of the V/III ratio on the surface morphology and the crystal quality of nonpolar a-GaN, a-plane GaN thin films with different ...
... SAPPHIRE AND QUARTZ WERE INVESTIGATED AS SUBSTRATE MATERIALS AND NEW MEASURING METHODS WERE DEVELOPED FOR ...
films can be produced on A-, M-, R-, and C-plane sapphire single crystal substrates by sputtering,2Epitaxial growth of ZnO thin films on R-plane sapphire substrate by radio frequency magnetron ZnO thin films were deposited on a R-plane sapphire substrate. The effects of the ...
grown on SiC or sapphire substrates. Sapphire substrates are relatively cheap, but their low thermal for multi-finger HEMTs: a flip-chip integration and an integration where the sapphire substrate is removedN amplifier is to be found in the use of SiC ...
IR optical properties of a UV grade sapphire are reported at moderate temperatures, up to 500 �C. The spectral transmittance of the sapphire is obtained as a function of temperature and thickness. With extinction and reflection coefficients obtained by fitting the transmittance curves, the emittance and reflectance of the sapphire ...
The magnetoresistive response of as-grown and nano-structured thin Nb films was studied by transport measurements performed in a rotating-current scheme at different temperatures. Epitaxial Nb(110) oriented thin films have been prepared by DC magnetron sputtering onto a-plane (11\\bar 20 ) sapphire substrates. Periodically arranged ...
Non-polar, A-plane (112�0) ZnO films are epitaxially grown on R-plane (11�02) Al2O3 substrates by plasma-assisted molecular-beam epitaxy and structural and optical properties are investigated. Epitaxial relationships between ZnO films and Al2O3 substrates are determined to be ZnO(112�0)//AlO(11�20), ZnO[1�100]//AlO[112�0]. ...
The family of III-V nitrides are wide band-gap semiconductors with a broad range of opto-electronic applications in LEDs, laser diodes, UV detectors as well as high temperature/high frequency devices. Due to the lack of good quality native substrates, GaN is grown on foreign substrates that have a lattice and thermal mismatch with GaN. This results in a ...
... This thesis studies the effects of changing the substrate material of an existing GaN HEMT from sapphire to diamond through the use of ...
Although there are several significant advantages to using single crystal sapphire as substrate material for hybrid microcircuits, the sizing of this material can be far more troublesome than the sizing of alternate material, such as polycrystal alumina. ...
... Abstract : In this presentation, the major issues, which confronted the formation of very thin layers of silicon (30-100 nm) on sapphire substrates for ...
Potential Commercial Applications: Microwave device applications which could benefit from the availability of high-Tc films on sapphire substrates include ...
... Accession Number : ADD016531. Title : Microdynamic Devices Fabricated on Silicon-On-Sapphire Substrates. Descriptive ...
... Accession Number : ADA523728. Title : Integrated Optical Pumping of Cr & Ti-Doped Sapphire Substrates With III-V Nitride Materials. ...
... Abstract : Factors affecting the wetting and bonding of nickel to sapphire (alpha ... of the sapphire substrate and a 'locking-in' of the contact angle had a ...
... Title : High-Temperature Wetting of Sapphire ... of atmosphere on contact angle, substrate reactions ... significant effect on the observed contact angles. ...
... Title : Growth and Morphology of Er-Doped GaN on Sapphire and Hydride Vapor Phase Epitaxy Substrates. Descriptive Note : Journal article. ...
such as silicon, sapphire, diamond etc. and the films on such substrates ... CeO 2 buffered. R-plane. Sapphire. : In this case, the lattice mismatch between ...
Properties of Si films grown on (\\bar{1}012) sapphire substrates by means of the plasma dissociation of silane depend on the substrate temperature, the applied r-f power and the ion species implanted on the surface region of sapphire substrate before the epitaxial growth. A Si film with good ...
An effective approach to enhance the light output power of InGaN/GaN light emitting diodes (LED) was proposed using pyramidal patterned sapphire substrates (PSS). The sapphire substrates were patterned by a selective chemical wet etching technique. GaN-based LEDs were fabricated on patterned ...
We report on the reduction of defect densities in non-polar a-plane GaN films over r-plane sapphire achieved by epitaxial laterally overgrowth (ELOG) approach. A mask pattern was used to produce ELOG GaN with wing region width of about 30 ?m. Based on transmission electron microscopy (TEM) results, the window regions have stacking faults density of 106 ...
Thin films of Heusler alloys Co2MnSn and Co2MnGe prepared on sapphire a-plane substrates by RF-sputtering have been investigated by ferromagnetic resonance (FMR) technique. The magnetic anisotropies of the Co2MnSn and Co2MnGe thin films have been probed and the effective magnetization values have been extracted. Weak in-plane ...
A pyramidal pattern was produced on a c-plane sapphire substrate by a mask-free etching process. Photoluminescence (PL) results show that a GaN-based light-emitting diode (LED) epilayer grown on the pyramidally patterned sapphire substrate has higher epitaxial quality than that grown on a standard flat c-plane ...
Template-Free Directional Growth of Single-Walled Carbon Nanotubes on a- and r-Plane Sapphire Song of SWNTs using iron-film-coated sapphire substrates, but no orientation control and, hence, no ordered on miscut c-plane sapphire substrates;7 however, there is currently a lack of control over ...
The goal of this proposal was to investigate the potential advantages of integrating III-V nitride structures on doped sapphire substrates and doped sapphire waveguide structures. III-V Nitride structures are typically grown on undoped synthetic sapphire ...
in the crystal orientation and the hardness of sapphire itself [1]. Especially, to obtain reliable deviceDry etching of sapphire substrate for device separation in chlorine- based inductively coupled In this study, sapphire wafers were etched using magnetized inductively coupled plasmas (MICP) and their etch
) Abstract Polycrystalline diamond films were grown on single crystal sapphire substrates using hot filament material onto which doped diamond is deposited. Other possible substrates, such as single-crystal sapphire the stresses within the crystal. The interface between the sapphire and the ...
The effect of substrates on the Raman spectrum of graphene: Graphene- on-sapphire and graphene The authors investigated the influence of substrates on Raman scattering spectrum from graphene. The room-temperature Raman signatures from graphene layers on GaAs, sapphire, and glass substrates were ...
We report on the growth and fabrication of nonpolar a-plane light emitting diodes with an in-situ SiNx interlayer grown between the undoped a-plane GaN buffer and Si-doped GaN layer. X-ray diffraction shows that the crystalline quality of the GaN buffer layer is greatly improved with the introduction of the SiNx interlayer. The electrical properties are ...
A-plane InxGa1-xN/GaN (x=0.09, 0.14, 0.24, and 0.3) multiple-quantum-wells (MQWs) samples, with a well width of about 4.5 nm, were achieved by utilizing r-plane sapphire substrates. Optical quality was investigated by means of photoluminescence (PL), cathodoluminescence, and time resolved PL measurements (TRPL). Two distinguishable ...
Gallium Nitride (GaN) Nanowires (NWs) have successfully been grown via a chemical beam epitaxy method. Source gases of Trimethylgallium (TMGa) and Ammonia (NH3) are impinged directly onto a hot growth substrate (�800 C) in high vacuum (�1x10-8 torr, base; �1x10-5 torr, growth). A thin metal film acts as catalyst, but NWs were also grown without catalyst. By this method ...
Ion beam mixing of thin metallic films deposited on sapphire substrates was studied for chromium or zirconium films deposited on single crystalline (alpha)-Al(sub 2)0(sub 3) substrates. Evidence for the influence of equilibrium thermodynamic factors was s...
The effect of implantation of different ion species on the adhesion of iron films to sapphire substrates has been investigated. The implantation energies were adjusted to ensure the ion concentration profiles, damage profiles, and recoil distributions wer...
The adhesion of aluminum (Al) films onto sapphire substrates in the presence of controlled contaminants is being investigated. In this study, adhesion strength is evaluated by continuous scratch and nanoindentation tests to induce delamination of the Al f...
has been reported on GaN contacts formed on an r-plane. Sapphire substrate operating 500� C [7]. Furthermore,. Sapphire is a potential substrate for System in ...
The influence of substrate condition and evaporation parameters on the development of structure in single crystal niobium and vanadium films condensed in vacuum onto sapphire substrates has been investigated by electron diffraction. (AIP)
SiGe/Si n-type modulation doped field effect transistors (MODFETs) fabricated on sapphire substrates
NASA Technical Reports Server (NTRS)
This report covers a sequence of epitaxial growth runs on sapphire substrates. The gallium arsenide films resulting do not have as good a surface morphology as the films previously grown on silicon-on-sapphire substrates. However, the films are highly ori...
... CRYSTALLINE, EPITAXIAL LINBO(3) FILMS WITH STOICHIMETRY COULD BE PREPARED ON SAPPHIRE SUBSTRATE AT 250 DEGREE C ...
... Descriptive Note : Patent,. ... Descriptors : *Patents, *Reticles, Optical equipment, Aluminum, Titanium, Sapphire, Substrates, Etching, Optical lenses. ...
... Descriptive Note : Patent,. ... Descriptors : *Patents, *Fabrication, *Diodes, *Aluminum compounds, *Nitrides, Sapphire, Substrates, Emittance. ...
... ADDITION, ETHANOLS, FUNCTIONS, GELS, LAYERS, LITHIUM ... PREPARATION, PROCESSING, SAPPHIRE, SILICON, SUBSTRATES, ...
... IRRESPECTIVE OF THE SUBSTRATE ORIENTATION. ... SIMULATIONS SHOWED THAT SAPPHIRE IS ALUMINUM ... FOR THE R-PLANE AT THE ...
This citation summarizes a one-page announcement of technology available for utilization. Results from the fabrication of high-contrast CRT faceplates favor sapphire as a substrate instead of the commercially-produced aluminosilicate glass. A study found ...
that in turn affect the device properties. To avoid such effects, in the past, R-plane sapphire substrates have by the sputtering technique on sapphire substrates (hexagonal structure as that of ZnO and excellent thermal with many other wide band gap optoelectronic materials [12]. Sapphire ...
on A- and R- plane sapphire substrates at an applied field of 2 mT. Clearly, flux penetration in the R showed that such rough flux penetration takes place in niobium thin films on R-plane sapphire substrates in superconducting niobium thin films on A-plane �1120� sapphire ...
Scanning tunneling microscopy observation of surface reconstruction of GaN on sapphire and 6H-SiC A of the surface structure of MBE-grown GaN layers on sapphire (0001) and 6H-(0001) SiC substrates. A different set on MOCVD GaN/ sapphire substrates, while the nitrogen-face has been obtained on ...
The purpose of this contract is to effect a significant improvement in the quality and economics of sapphire substrates for thin film microassemblies. It is expected to achieve these results by producing larger diameter crystals of good internal quality, ...
respectively, substrate temperature is 10000 C, and R-plane sapphire is used as substrate: The g rowth rate, carrier concentration, and mobility ...
Resonant micro-Raman spectroscopy of aligned single-walled carbon nanotubes on a-plane sapphire to characterize aligned single-walled carbon nanotubes grown on a-plane sapphire to address the alignment massively aligned nanotubes on insulating substrates such as sapphire and quartz.2�7 Epitaxial growth
Determination of the epitaxial growth of zinc oxide nanowires on sapphire by grazing incidence growth on sapphire substrates is epitaxial and demonstrates the crystallographic relation between the two the sapphire and the nanowires was directly probed by using XRD at grazing angles of incidence, where
of Crystal Growth 312 (2010) 1311�1315 #12;ARTICLE IN PRESS 2. Nano-patterning of AGOG sapphire substrate metallic aluminum (Al) into single crystal sapphire via a two stage annealing process. The acronym ``AGOG) second stage anneal at 1200 1C in air to induce grain growth of the underlying sapphire single ...
Conventional III:nitride devices are grown on sapphire or SiC. This heterogeneous growth induces significant performance limiting aspects, such as stress and high dislocation densities for the resultant devices. Physical Vapor Transport (PVT) growth of AlN was investigated to produce free standing crystals suitable for homogenous substrate use. AlN bulk ...
Conventional c-plane (Al, In, Ga)N optoelectronic devices suffer from deleterious polarization effects. These polarization effects can be eliminated by growing devices on alternative orientations of GaN crystals, such as {11�00} m-plane or {112�0} a-plane films. Previous attempts to grow nonpolar GaN by HVPE, yielded rough and faceted surfaces that were unsuitable for ...
Sapphire substrates were patterned by a chemical wet etching technique in the micro- and nanoscale to enhance the light output power of InGaN/GaN light-emitting diodes (LEDs). InGaN/GaN LEDs on a pyramidal patterned sapphire substrate in the microscale (MPSS) and pyramidal patterned sapphire ...
Epitaxial thin films of Al-doped zinc oxide have been grown on sapphire substrates by pulsed laser ablation. The effect of substrate temperature, background pressure of oxygen, and substrate orientation (A, M, R, C) on the orientation relationships between ZnO and sapphire have been evaluated ...
crystal quality of CdTe layers grown on sapphire. Our results also suggest that factors like thermal substrates like sapphire, GaAs, and CdTe wafers. The growth was carried out at the temperature 340 �CAs, or sapphire by metalorganic vapor phase epitaxy MOVPE .1 Several characterization tech- niques have been ...
to the presence of GaN nanowires on a sapphire substrate. Controlled growth of single-crystal GaN nanowires grown primarily normal to the surface of a sapphire substrate has a dramatic influence sapphire at values of incident angle greater than 72�. � 2003 American Institute of Physics. ...
We have fabricated refractive sapphire microlenses and characterized their properties for what we believe to be the first time. We use thermally reflown photoresist lenslet patterns as a mask for chlorine-based dry etch of sapphire. Pattern transfer to the mechanically hard and chemically inert sapphire substrate ...
Work carried out to determine the effect of Silicon On Sapphire (SOS) wafer fabrication process on radiation induced leakage in SOS devices is described. The experimental material matrix studied includes various sapphire substrate pre-epitaxy annealing sc...
(M- and R-plane, respectively)_. The optic axis in M-plane sapphire is aligned parallel to the substrate surface, whereas in R-plane sapphire it is oriented ...
It has been shown previously that alumina (sapphire) whiskers grown on single-crystal alumina grow coherently with and in the directions of screw dislocations in the substrate. A possible explanation is that the whiskers grow by the screw-dislocation mech...
We report growth of InGaN/GaN multi-quantum well (MQW) and LED structures on a novel composite substrate designed to eliminate the coefficient of thermal expansion (CTE) mismatch problems which impact GaN growth on bulk sapphire. To form the composite substrate, a thin sapphire layer is wafer-bonded to a ...
This paper describes the use of thermal wave technology for monitoring implant damage in sapphire substrate wafers. The information obtained is not easily obtainable from other techniques, such as UV reflectance or IR reflectance measurements. In CMOS/SOS device and circuit fabrication it is often desirable to monitor the effects of implant damage in the ...
We have developed metal-oxide graphene field-effect transistors (MOGFETs) on sapphire substrates working at microwave frequencies. For monolayers, we obtain a transit frequency up to ~80 GHz for a gate length of 200 nm and a maximum oscillation frequency of about ~3 GHz for this specific sample. Given the strongly reduced charge noise for nanostructures on ...
Single crystalline Ru(0001) thin films epitaxially grown on sapphire (0001) substrates were used as sacrificial metal templates for the synthesis of high-quality graphene with uniform monolayer thickness and full surface coverage. Removal of the metal template by etching transferred monolayer graphene with good crystal quality onto the insulating ...
This paper analyses the influence of the sapphire substrate on stress in GaN epilayers in the temperature range between 4K and 600K. Removal of the substrate by a laser assisted liftoff technique allows, for the first time, to distinguish between stress and other material specific temperature dependencies. In contrast to the prevailing ...
Undoped a-plane GaN layers grown by metal-organic vapour phase epitaxy on sapphire (1 0 ? 1 2) substrates using low temperature (LT) GaN seed layers and in situ SiN masks were characterized by Hall-effect measurements, CV-characteristics and photovoltage spectroscopy. With increasing deposition time of the SiN masks the electron ...
The wide-band-gap zinc oxide-based diluted magnetic semiconductors currently attract considerable attention due to their possible use in spintronic devices. In this work, we studied ZnO nanowire samples synthesized on 10�10 mm2 a-plane sapphire substrates by high-pressure pulsed laser deposition. The samples were characterized by ...
As-grown MgB2 thin films were deposited on r-plane (112) and c-plane (001) sapphire substrates by using a carrousel-type magnetron sputtering system. Even though the respective critical temperature and residual-resistivity ratio of the MgB2 films deposited on r- and c-plane sapphire substrates were nearly the same ...
Patterning sapphire substrate can relax the stress in the nitride epilayer, reduce the threading dislocation density, and significantly improve device performance. In this article, a wet-etching method for sapphire substrate is developed. The effect of substrate surface topographies on the ...
The adhesion of aluminum (Al) films onto sapphire substrates in the presence of controlled contaminants is being investigated. In this study, adhesion strength is evaluated by continuous scratch and nanoindentation tests to induce delamination of the Al film from the sapphire substrate. If delamination blisters or ...
DOE Information Bridge
Growth of A1N on patterned sapphire substrates was studied. Deep grooves were made on sapphire substrates by a laser-induced backside wet etching technique. KrF excimer laser was irradiated at an interface between sapphire and phenolphthalein/N-methyl-2-pyrrolidone solution, which acts as a ...
molecular precursors and prepared highly crystal- line MgO �lms on Si(100) and c-plane sapphire at substrate Abstract Thin �lms of MgO have been deposited on Si(100) and c-plane sapphire substrates by the metal] oriented polycrystalline MgO �lms were obtained on both Si(100) and c-plane ...
The metastable A15 V3Al phase was obtained on glazed alumina (glass-coated alumina) and Au-coated sapphire substrates by sputtering using a composite target of Al and V. However, the metastable phase was not formed on sapphire or Ag-coated sapphire substrates. From the depth profile of the ...
Unidirectional growth of single-walled carbon nanotubes (SWNTs) was achieved using the patterned Co-Mo salt catalyst on the r-plane sapphire substrate. This is in marked contrast with the SWNTs grown on an a-plane sapphire and ST-cut quartz, on which the SWNTs grew bidirectionally. This new growth mode is not dependent on the gas flow ...
. Kondilenko "Absorption Studies in Optical Coatings and Sapphire Crystals", presentation at the LIGO suspensions incorporating fused silica fibers or ribbons jointed to test masses of sapphire or fused silica.6 sizes etc, has left two candidates for consideration as transmissive substrates: -sapphire and fused
of submicron GaN islands on GaN-sapphire, AlN-sapphire, and bare sapphire substrates. It is shown that strain, homoepitaxially grown crystals. It is proposed that the strain dependency of Ehrlich-Schwoebel barriers across emitters8 and as optoelec- tronic components.9 The impact of crystal morphology and faceting
The structural and optical properties of GaAs grown by molecular-beam epitaxy on (0001) and (01(1-bar)2)-oriented sapphire substrates are evaluated for possible direct deposition on sapphire optical fibers and optoelectronic device applications. X-ray dif...
Iron-doped sapphire thin films have been successfully epitaxially grown onto sapphire single crystal substrates by electron beam deposition and subsequent thermal annealing. Amorphous Al(sub 2)O(sub 3) thin films, about 280--390 nm thick, cation doped wit...
to create parallel sapphire posts off of which GaN is laterally overgrown. Figure 1 shows a coalesced CE of the sapphire post turn over and run horizontally i.e. parallel to the sapphire substrate. Further study reveals techniques such as epitaxial lateral overgrowth (ELO) when steps are taken to insure that the ...
a novel AGOG process that enables creation of single crystal Al2O3 islands on the sapphire substrates. The "AGOG" is an acronym for the process of conversion Al into single crystal sapphire, by employing growth of the underlying sapphire single crystal to consume the oxide layer [shown in Fig. 2(b
... GALLIUM COMPOUNDS, X RAY DIFFRACTION, SINGLE CRYSTALS, SUBSTRATES, NITRIDES, SAPPHIRE, CRYSTAL DEFECTS, THERMAL ...
... c-axis perpendicular to the film-substrate interface. Films with higher concentrations of water of hydrolysis on sapphire had a preferred orientation ...
AlGaN/GaN high electron mobility transistors are very promising for microwave power applications. Integration and packaging of those high power density devices requires specific attention to thermal management, especially when the AlGaN/GaN heterostructures are grown on sapphire substrates. Indeed, the low thermal conductivity of ...
... ions in the silicon-on-sapphire crystal lattice has been ... Descriptors : (*SINGLE CRYSTALS, *SILICON), (*FILMS, SILICON), SUBSTRATES, DOPING ...
... quality factors of single-defect photonic-crystal resonant cavities ... slabs patterned with two-dimensional photonic crystals on a sapphire substrate. ...
... Abstract : The polarity-controlled growth of Gallium Nitrides (GaN) on a sapphire substrate by metalorganic vapor phase epitaxy (MOVPE) and ...
output frequency by selecting substrate orientation angle was also estab- ...... grows well on both R- and basal plane sapphire. As a result, both R- and ...
A process for growing high transition temperature superconducting films of yttrium-barium-copper-oxide on sapphire or lanthanum aluminate substrate ...
The overall objective of the program was the development of reliable high yield processes for bonding fine wires of gold and aluminum to gold-chromium and aluminum films on various substrates such as alumina, sapphires, and oxidized silicon. Furthermore, ...
... Pagination or Media Count : 29. Abstract : Enhancement and depletion mode JFETs have been fabricated on silicon-on-sapphire substrates. ...
Prior to circuit fabrication, all substrates are cleaned using a standard semiconductor process. The R-plane Sapphire is 430 ...
... Title : Growth and Characterization of GaN on C-Plane (0001) Sapphire Substrates by Plasma-Enhanced Molecular Beam Epitaxy. ...
The silicon is grown by the pyrolysis of silan q in a multiwafer system on the face of polished sapphire substrates. The gate insulator of both devices I ...
... SUBSTRATES, REFLECTION, BEAM SPLITTING, REGIONS ... SAPPHIRE, ELECTRON BEAMS, PARTICLES ... RADIATION, DIRECT CURRENT, NEAR ...
... films were grown on (0001) (C-plane) and (1120) (plane) oriented sapphire substrates by the reduction of sol-gel derived vanadium oxide films. ...
... Title : Development of High Frequency Surface Acoustic Wave Devices Using MOCVD ZnO Piezoelectric Thin Films on Sapphire Substrates. ...
... substrate such as sapphire which has large lattice mismatched wit GaN. ... the structures are grown by conventional MOCVD epitaxial growth method. ...
... sapphire, brace 111 brace oriented lanthanum aluminate, brace 110 brace oriented spinel, brace 111 brace oriented thorium dioxide, brace 001 ...
Jan 22, 2011... layers on SiC and sapphire substrates is examined using high resolution transmission electron microscopy and atomic force microscopy. ...
The potential of nonpolar a-plane InGaN/GaN multi-quantum wells (MQWs), which are free from a strong piezoelectric field, was demonstrated. An a-GaN template grown on an r-plane sapphire substrate by the multi-buffer layer technique showed high structural quality with an omega full width at half maximum value along the c-axis of 418 ...
A systematic investigation of the growth of AlN, InN,and InAlN by Plasma Source MBE (PSMBE) was performed. The growth conditions were optimized based on RHEED analysis during growth and dissociation RGA experiments. For the PSMBE technique, the most important growth parameters are the flux levels (as determined by RF power and Ar/N ratio), and growth temperature. We present experimental work on ...
This paper reports the application of novel contact printing lithography to fabricating patterned sapphire substrates (PSSs) used in light emitting diodes (LEDs). This contact printing lithography method can directly transfer a metal film pattern from a silicon mold to a sapphire substrate, and subsequently use the ...
We have synthesized GaN nanocrystals by sequential implantation of Ga and N ions into a sapphire substrate followed by a postimplantation anneal. The nanocrystals have been identified as the wurtzite phase {alpha}-GaN structure by transmission electron microscopy. We also found that the nanocrystals are aligned with the sapphire ...
The authors previously developed a sapphire nitridation method using carbon-saturated N2-CO gas mixture to form a high-quality AlN film for III-nitride-based optoelectronic devices. In this study, the nitridation behavior of (0001) (c) plane and (1120) (a) plane sapphire was studied to elucidate and optimize the ...
Although there are several significant advantages to using single crystal sapphire as substrate material for hybrid microcircuits, the sizing of this material can be far more troublesome than the sizing of alternate material, such as polycrystal alumina. The work done in developing a satisfactory method of sizing single crystal ...
Journal of Crystal Growth 293 (2006) 273�277 A study of semi-insulating GaN grown on AlN buffer/sapphire-temperature GaN interlayer. In comparison with the normal GaN grown on sapphire, the crystal quality crystal quality of thick SI-GaN layers grown on an AlN buffer layer/sapphire substrate by MOCVD
I. Calizo, W. Bao, F. Miao, C.N. Lau and A.A. Balandin, "Graphene-on-Sapphire and Graphene-on-Glass" 2007 1 Graphene-on-Sapphire and Graphene-on-Glass: Raman Spectroscopy Study Irene Calizo Nano-temperature Raman signatures from graphene layers on sapphire and glass substrates were compared with those from
The possibility of characterizing a number of practically important parameters of sapphire substrates by X-ray methods is substantiated. These parameters include wafer bending, traces of an incompletely removed damaged layer that formed as a result of mechanical treatment (scratches and marks), surface roughness, damaged layer thickness, and the specific ...
A sapphire-etched vertical-electrode nitride-based semiconductor (SEVENS) light-emitting diode (LED) has been fabricated by a selective wet etching technique. The light output power of the SEVENS LED is substantially enhanced compared with a conventional NiAu lateral-electrode (LE) GaN-based LED formed on a sapphire substrate. The ...
Oxygen radicals pregrowth treatment and surface nitridation were used to eliminate Zn-polar inversion domains and control the growth of single-domain O-polar ZnO film on sapphire (0001) substrate by rf plasma-assisted molecular beam epitaxy. We found that the formation of oxygen-terminated sapphire surface prior to nitridation is ...
The strain in a -plane GaN layers of different thickness grown on r -plane sapphire substrates by hydride vapor phase epitaxy was studied by X-ray diffraction. The layers are found to be under compression in the growth plane and under tension in the growth direction. Therefore, the symmetry of the GaN unit cell is no longer hexagonal but orthorhombic. With ...
We report on the design and fabrication of a planar integrated free-space optical system working on the basis of binary phase diffractive optical elements (DOEs) realized in GaN on a sapphire substrate. Group III-nitride/sapphire substrates enable the parallel monolithic integration of passive microoptical elements ...
, polycrystalline Al2O3 and single crystal sapphire substrates [17]. Paired plated formation observed on this study (7001C, 1 h) stoichiometric PLZT 9/ 65/35 film on r-sapphire is illustrated in Fig. 3. Crystal-plate precipitate formation in Pb0.91La0.09Zr0.65Ti0.35O3 films grown on sapphire ...
We applied the laser interference lithography method to form a patterned sapphire substrate (PSS). A three-dimensional photonic crystal was formed by autocloning the PSS with alternate Ta2O5/SiO2 coatings. A high total integrated reflectance (TIR) band was obtained around the 410 to 470?nm wavelength range that matched the emission spectrum of the gallium ...
Cathode damage was studied after a vacuum arc was initiated between parallel plate electrodes. The cathode plate consisted of thin gold films (0.028 to 1.8 ..mu..m) on sapphire substrates. The damage was in the form of spot where gold was removed from the sapphire, apparently by having been splattered out. The spot diameters were ...
GaN films on sapphire substrates are obtained using the metal-organic chemical vapor deposition growth technique. We present two methods to reduce the GaN wafer bowing caused by the mismatch of the thermal expansion coefficients (TECs) between the film and the substrate. The first method is to use coating materials on the back side of ...
ZnO film growth on sapphire and zirconium boride single crystals by the molecular beam epitaxy method was investigated. A Zn metal film could not be grown on sapphire substrates at room temperature, while an incommensurate Zn film could be grown on a zirconium boride substrate. The incommensurate Zn film could be ...
A new process to control the electrical conductivity of gallium nitride layers grown on a sapphire substrate has been developed. This process is based on initially coating the sapphire substrate with a thin layer of aluminum nitride, then depositing the gallium nitride thereon. This process allows one to ...
SiGe/Si n-type modulation doped field effect transistors (MODFETs) fabricated on sapphire substrates have been characterized at microwave frequencies for the first time. The highest measured room temperature electron mobility is 1380 cm(sup 2)/V-sec at a ...
High mobility n-type SiGe/Si transistor structures have been fabricated on sapphire substrates by ion implanting phosphorus ions into strained 100 for the first time. The strained Si channels were sandwiched between Si(0.7)Ge(0.3) layers, which, in turn, ...
Al(x)Ga(1-x)N were grown on (00.1) sapphire and (111) silicon substrates in the whole composition range (0 (less than or equal) x (less than or equal) 1). The high optical quality of the epilayers was assessed by room-temperature optical absorption and ph...
The growth of Al2O3 on single crystal sapphire and ruby substrates via the net chemical reaction 2 AlCl3(g) + 3 H2O(g) = Al2O3(s) + 6 HCl(g), was investigated in the temperature range from 1400 to 1600C. Deposits that were obtained varied from polycrystal...
The ionic conductivity of LiI thin films grown on sapphire(0001) substrates has been studied in-situ during deposition as a function of film thickness and deposition conditions. LiI films were produced at room temperature by sublimation in an ultra-high-v...
Cathode damage was studied after a vacuum arc was initiated between parallel plate electrodes. The cathode plate consisted of thin gold films (0.028 to 1.8 mu m) on sapphire substrates. The damage was in the form of spot where gold was removed from the sa...
Controlled-geometry voids were introduced into unimplanted and Ti-implanted high-purity c-axis sapphire substrates using microfabrication techniques and ion beam etching, and subsequently transferred to an internal interface by hot-pressing. The morphological evolution of cracklike and channellike defects oriented parallel to the basal plane in response to ...
The development of the composite superconducting transition edge bolometer is reported. The temperature sensitive element is an aluminum strip evaporated onto the sapphire substrate. A bismuth film evaporated on the reverse side of the substrate is used t...
The investigation establishing boundaries between regions of substrate orientations in which different silicon-sapphire relationships occur was brought to a conclusion. Additional relationships not previously reported have been found, viz..(111) Si // (10...
We have studied YBCO films on three different substrates. : (i) (100) oriented. LaA10 3 (ii) R- plane Sapphire with a buffer layer of (100) CeO 2 (iii) ...
The growth and characterization of the 111-V nitrides has been the focus of intense effort. A major problem plaguing nitride growth has been the absence of a good substrate to grow on. Currently sapphire and 6H-SiC are the substrates of choice for nitride...
substrates by ion implanting phosphorus ions into strained 100 ... via ion implantation and post-annealing. The high electron mobility and short surface-to - ...
substrates of R-plane sapphire and alumina, both coated with 50 nm of. CeO. 2 . The design employed was identical to type 3 on MgO substrates. Clearly these ...
each using substrates of R-plane sapphire and alumina, both coated with 50 nm of . CeO 2. The design employed was identical to type 3 on MgO substrates. ...
) substrate (b) and planar sapphire (11/ �2/ 0) substrate (c). The inset shown indicates the crystal) by a factor of 4. A cross-sectional TEM micrograph of the Al0.04- Ga0.96N single crystal grown on the PG�/sapphireLow-dislocation-density AlxGa1(xN single crystals grown on grooved ...
GaN-based light-emitting diodes (LEDs) were fabricated on a micro-lens patterned sapphire substrate (ML-PSS). ML patterning on the sapphire substrate was carried out by using photolithography with photo-resist reflow technique and dry etching process using chlorine based inductively coupled plasma. The ML-PSS was ...
Iron-doped sapphire thin films have been successfully epitaxially grown onto sapphire single crystal substrates by electron beam deposition and subsequent thermal annealing. Amorphous Al{sub 2}O{sub 3} thin films, about 280--390 nm thick, cation doped with iron have been deposited on [0001] oriented sapphire ...
Numerical analyses of the ultraviolet and visible plasmonic spectra measured from hemispherical gallium nanostructures on dielectric substrates reveal that resonance frequencies are quite sensitive to illumination angle and polarization in a way that depends on nanostructure size, shape, and substrate. Large, polarization-dependent splittings arise from ...
A semiconductor device comprising an insulating substrate such as sapphire and a semiconductor element region formed on the substrate, wherein an insulating layer containing yttrium or a lanthanide element is interposed between the substrate and semiconductor element region. A method of manufacturing a ...
We have fabricated DNA network structures on glass and sapphire substrates. As a comparison, we also formed the network structure on mica substrate. For titanate strontium substrate, however, DNA network can not be obtained even if it is wet-treated by Na2HPO4 solution to make it hydrophilic. We also discuss the ...
The polarity of molecular-beam epitaxy grown ZnO films was controlled on nitrided c-sapphire substrate by modifying the interface between the ZnO buffer layer and the nitrided sapphire. The ZnO film grown on nitrided sapphire was proven to be Zn-polar while the O-polar one was obtained by using gallium ...
The ablation behavior of single crystalline sapphire with nanosecond laser pulses at 157 nm wavelength is investigated. Ablation rates of about 10 to 100 nm/pulse are obtained at fluences ranging from 1 to 9 J/cm2. At moderate fluences, incubation behavior is observed, i.e. ablation starts after material modification by a number of laser pulses. The ablation can be utilized to ...
InGaN-based light-emitting diodes (LEDs) grown on triangle-shaped patterned sapphire substrates were separated through a chemical lift-off process by laterally etching an AlN sacrificial layer at the GaN/sapphire substrate interface. After the epitaxial growth, an air-void structure was observed at the patterned ...
The nucleation and initial growth of gallium nitride (GaN) films on sapphire substrates using hydride vapor phase epitaxy (HVPE) technique depends on many factors including the chemical treatment of sapphire surface, nitridation, and the specific growth conditions. Liquid and gas phase treatments of the sapphire ...
Sapphire is a preferred substrate for high frequency applications where small dielectric constants and low loss tangents are required. It is also much cheaper than other oxide substrates such as SrTiO{sub 3}, LaAlO{sub 3}, NdGaO{sub 3}, MgO, and yttria-stabilized zirconia (YSZ) for high T{sub c} superconducting thin films. ...
GaN films were grown by hydride vapor phase epitaxy on sapphire substrates with orientations c-(0 0 0 1), a-(1 1 2� 0), m-(1 0 1� 0) and r-(1 0 1� 2) using N2 as a carrier gas. The crystalline perfection of the grown films was studied by X-ray diffraction, by optical microscopy and scanning electron microscopy and by microcathodoluminescence (MCL). ...
In a method of producing an inverted rib waveguide laser including an InP substrate having a (100) surface and an (InGa)(As,P) active layer, the improvement is described which consists of: forming at the (100) surface of the substrate a channel extending in the (011) direction by an etching process producing side walls of the channel that differ from ...
Microstructure of epitaxial thin films grown on sapphire substrates using the metal organic chemical vapor deposition technique were found to depend on the substrates surface structure. Epitaxial TiO[sub 2] films grown on the sapphire (0001) substrates were highly-oriented polycrystal and the ...
Microstructure of epitaxial thin films grown on sapphire substrates using the metal organic chemical vapor deposition technique were found to depend on the substrates surface structure. Epitaxial TiO{sub 2} films grown on the sapphire (0001) substrates were highly-oriented polycrystal and the ...
There are three sources of strain in heteroepitaxial growth, lattice misfit; thermal misfit; and growth related defects. The primary aim of the present work was to do a fundamental study of strain and mechanisms for strain relaxation in epitaxial growth of polar-GaN and polar and nonpolar-ZnO thin films grown on sapphire substrates. We have shown that ...
Epitaxial TiO{sub 2} films have been successfully grown on sapphire substrate at temperatures from 400 to 800{degree}C by thermally decomposing titanium isopropoxide in the presence of O{sub 2} in a cold wall low pressure MOCVD system. Rutile film was grown on sapphire (11{bar 2}0) at 800{degree}C with (101) being the growth plane and ...
The chemical, morphological, and structural characteristics of nitrogen plasma treated c-plane sapphire substrate surfaces were studied by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The plasma treatment was carried out by exposing sapphire ...
In this work, superconducting YBa2Cu3O7 (YBCO) thin films were grown on different substrates under the same conditions and their behaviours were investigated. At a higher substrate temperature, because of the occurrence of a chemical reaction between the substrate and film, the film quality was impaired, especially in case of the Al2O3 ...
a buffer layer. Despite repeated attempts, we were not able to grow Nb2AlC films on substrates of Si, R-plane and characterization of epitaxial c-axis oriented Nb2AlC thin films deposited on c-axis sapphire (Al2O3) substrates�18 mTorr. Substrates of MgO (111), Si (100), c- (00 l) and r-plane (012) ...
We present our first-principles total-energy calculations performed for carbon nanotubes (CNTs) on sapphire substrates. We find that the formation of covalent and partly ionic bonds between Al and C atoms on the Al-rich surfaces causes the selective alignment of CNTs, this being the principal reason for the CNT growth along particular crystallographic ...
Journal of Crystal Growth 300 (2007) 37�41 Formation of large-area freestanding gallium nitride substrates by natural stress-induced separation of GaN and sapphire Adrian D. Williams�, T.D. Moustakas. A number of GaN thick films were grown onto sapphire substrates by the hydride vapor-phase epitaxy (HVPE
We report epitaxial growth by laser ablation of YBa2Cu3O7 films on bare sapphire (1102) substrate. Owing to suitable substrate treatment, we have succeeded to grow superconducting YBCO films with Tc(R = 0) above 88 K and ?(300K)/?(100K) around 2.80; first promising Rs value of 17 m? was measured at 10 GHz and 77 K.
High Al content AlxGa1-xN (0.4sapphire substrates or on AlN films by alternative supply of group III metalorganics (trimethylaluminum and trimethylgallium) and NH3 in an inductively heated quartz reactor operated at atmospheric pressure. ?-2? x-ray diffraction data show a compositional separation ...
at the GaN/sapphire interface with those of the bulk crystals. Finally, the measured strain energy was added-VCH Verlag GmbH & Co. KGaA, Weinheim Epitaxial strain energy measurements of GaN on sapphire by Raman strain in the GaN epilayer grown on sapphire substrate by micro-Raman spectroscopy. Operating in ...
We demonstrate 2.6 �m mid-infrared lasing at room temperature in a planar waveguide structure. Planar waveguides were fabricated using pulsed laser deposition (PLD) by depositing chromium doped zinc selenide thin films on sapphire substrate (Cr2+:ZnSe/sapphire). Highly doped Cr2+:ZnSe/Sapphire thin film sample ...
