bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characteristics of Sulfur in OMVPE Grown Indium Phosphide
Authors: Tyagi S.D. , Ehsani H. , Ghandhi S.K. 
Published: March 2011

ABSTRACTDoping of indium phosphide, grown by organometallic vapor phase epitaxy (OMVPE), has been carried out using hydrogen sulfide. For low partial pressures of H2S, the carrier concentration in the epitaxial layers is found to increase linearly. However, for higher partial pressures a region of superlinear doping is seen. For still higher partial pressures, a rapid decrease in carrier concentration is seen. In the linear region, the doping has a weak dependence on phosphine pressure, however, peak carrier concentration is higher for lower phosphine pressures.The layers were studied using Hall Effect and Double Crystal X-Ray Diffraction, in order to elucidate the nature of impurities and compensating centers introduced. A model which explains the above characteristics is proposed for S incorporation in MOVPE grown InP.
Solid Phase Equilibria in the Ni-in-P System.
Authors: Andersson-Söderberg Margaretha 
Published: March 2011

ABSTRACTThe solid phase equilibria in the Ni-In-P system at 800 °C have been determined at ambient pressure using X-ray diffraction supplemented with differential thermal analysis from room temperature to 800 °C. One ternary phase, Ni21In2P6, was found in the system. It crystallizes with space group Fm3m and is isostructural with Cr23C6. Indium phosphide forms equilibria with the nickel phosphides Ni2P, Ni5P4, NiP2 and NiP3 and indium with Ni12P5 and Ni2P. The results are in agreement with previous observations that Ni2P is a stable phase when a nickel thin film deposited on InP is reacted to completion.
Doping Effects on the Etching Chemistry of GaAs and Si
Authors: Houle F. A. 
Published: March 2011

ABSTRACTDoping effects on semiconductor etching rates have been proposed to be associated with field effects in the near-surface region. Detailed investigations of the chemistry of nand p-type Si and GaAs indicate that the majority carrier can also play an important role in determining the reactivity of surface intermediates, providing an independent mechanism for influencing the etch rate. A microscopic picture of central driving forces in semiconductor etching deduced from the doping cffects is proposed.
Homoepitaxial Growth of Crystalline Ge Films through a Liquid Metal Medium at Low Temperature
Authors: Xiong Fulin , Golovehenko Jene A. , Spaepen Frans 
Published: March 2011

ABSTRACTCrystalline films of Ge have been homoepitaxially grown through a liquid Au medium by the so-called vapor-liquid-solid (VLS) mechanism at relatively low temperature (400-450 °C). During the process, the Ge vapor is delivered by a molecular beam evaporator and the liquid phase in the system is formed at the interface by heating a Au metal film above its eutectic point with the semiconductor. This process has a potential of a high growth rate at low temperature. The growth process and the crystallinity of the films were monitored in situ by high energy ion backscattering and channeling. The surface morphology and quality of the films were examined by scanning electron microscopy and cross-sectional transmission electron microscopy. The experimental results are presented, together with a discussion of the growth mechanism and the nature of the liquid metal-semiconductor interface.
Surface Reaction Mechanisms in Chemical Beam Epitaxy
Authors: Foord John S. , Singh Nagindar K. , Wee Andrew T.S. , French Cathy L. , Fitzgerald Emma T. 
Published: March 2011

ABSTRACTSurface reaction mechanisms which underly the growth of III-V semiconductors by chemical beam epitaxy have been investigated using a combination of surface spectroscopic techniques in conjunction with modulated molecular beam scattering techniques. Emphasis is placed on understanding the complex growth rate effects observed during the growth of Ga(Al,In)As and the origin of selected area epitaxy. These effects are shown to arise from the surface sensitive nature of the decomposition of the group III alkyl source chemicals used in CBE.
Adsorption and Decomposition of Diethylsilane on Silicon Surfaces
Authors: Coon P.A. , Wise M.L. , Dillon A.C. , Robinson M.B. , George S.M. 
Published: March 2011

ABSTRACTDiethylsilane (DES), Si(C2H5)2H2, is a promising candidate for the atomic layer epitaxy of silicon. The adsorption and decomposition kinetics of DES on silicon surfaces were studied using laser-induced thermal desorption (LITD), temperature programmed desorption (TPD), and Fourier transform infrared (FTIR) spectroscopy. FTIR studies on porous silicon surfaces indicated that DES dissociatively adsorbs below 600 K and produces Si-H and Si-C2H5 surface species. The desorption products following DES adsorption on Si(111) 7×7 were C2H4 and H2 for all surface coverages using both LITD and TPD techniques. Ethylene and H2 desorption occurred at 700 and 810 K, respectively, during TPD experiments with a heating rate of β = 9 K/s. Ethylene desorption was consistent with a β-hydrogen elimination mechanism from the Si-C2H2 surface species. Isothermal LITD studies monitored the desorption kinetics of C2 H4 from Sl (111) 7×7 as a function of time following DES exposures. The first-order ethylene desorption kinetics were Ed = 36 kcal/mol and vd = 2.7 × 109 s−1. Additional LITD measurements determined that le initial reactive sticking coefficient of DES on Si(111) 7×7 decreased versus surface temperature. The temperature-dependent sticking coefficients suggested a precursormediated adsorption mechanism.
A Molecular Beam Study of the Reaction of Molecular Chlorine with Gallium Arsenide
Authors: Su Chaochin , Dai Zi-Guo , Lee Gang Ho , Vernon Matt 
Published: March 2011

ABSTRACTMolecular chlorine is scattered from a GaAs(100) surface and the reaction products detected by a mass spectrometer. A careful analysis of the velocity and angular distributions of the reaction products as well as the vibrational energy dependence of the daughter ion fragmentation pattern shows that the steady state reaction is stoichiometric in the removal of Ga and As until the incongruent evaporation rate exceeds the etch rate induced by the incident chlorine flux. The depletion of the nonreactive molecular chlorine signal is accounted for by the flux of chlorinated reaction products. The absolute etch rates as well as the incident chlorine flux are determined from the known evaporation rate of GaAs at the incongruent evaporation temperature. Modulated molecular beam scattering is used to establish some necessary reaction steps.
Comparison of H2 Desorption Kinetics from Si(111)7×7 and Si(100)2×l
Authors: Wise M. L. , Koehler B. G. , Gupta P. , Coon P. A. , George S. M. 
Published: March 2011

ABSTRACTThe desorption kinetics of hydrogen from the β1 H2 -TPD state on Si(111)7×7 and Si(100)2×l were studied using laser-induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. Isothermal LITD studies of H2 desorption from Si(111)7×7 revealed second-order kinetics with a desorption activation energy of Ed = 62 ±4 kcal/mol and a preexponential factor of Vd = 92 ±10 cm2 /s. In contrast, H2 desorption from Si(100)2×l revealed first-order kinetics with an activation energy of Ed = 58 ±2 kcal/mol and a preexponential factor of Vd = 5.5 ±0.5 × 1015 s−1. The desorption kinetics yield similar upper limits for the Si-H bond energies but different desorption mechanisms on Si(lll)7×7 and Si(100)2×l.
Apid Thermal Oxidation of Silicon: Aspects of the Initial Regime Kinetics
Authors: Messaoud A. Yahia , Martinez A. , Sarrabayrouse G. , Scheid E. 
Published: March 2011

ABSTRACTThe kinetics of silicon oxidation by rapid thermal processing in the 1000-1200°C range have been studied with particular attention paid to the homogenization and optimization of the heating and to the initial conditions (i.e. sample preparation, insertion into the furnace and measurements of initial thickness ). Special emphasis has also been placed on the accuracy of thickness measurements using ellipsometry and adequate calculations. Comparison of the experimental and simulated thickhnesses using Han and Helms' model and comparative temperature evaluation, allowed the real temperature to be evaluated within ±5°C. Then, it was concluded that RTO kinetics does not reveal any special peculiarities in the 2-35 nm range.Electrical measurements of RTO capacitors (C-V, I-V, V-t) have been performed. Typically, a breakdown electrical field strength (Eox) of 15 MV/cm, a Nss max of 3.1011 eV−l.cm−2, a Nss midgap of 4.1010 eV−1.cm−2 and a Qbd (charge injected at breakdown) of 40 C.cm−2 were obtained for oxide thicknesses ranging from 8 to 10 nm. These compare favorably with our better standard oxides grown at 900°C with 2% HCI in O2. We can thus conclude that RTO is a very promising process for submicron technologies.
Very Low Pressure Oxidation of Si and Ge Surfaces
Authors: Baikie Iain D. 
Published: March 2011

ABSTRACTAlthough the oxidation of Si(111) 7×7, Ge(111) 2×8 surfaces are relatively well understood very little work has been performed at sub monolayer coverage. We have utillsed a custom-built high resolution Kelvin probe to follow the changes in work function, and changes in band-bending and surface state occupancy via Surface Photovoltage Spectroscopy (SPV). The Kelvin probe Is an Ideal tool for such analysis due to Its extremely high surface sensitivity, equivalent to 4×1010 molecules/cm2, or 0.01% of the available sites.We observe a very rapid initial adsorption phase, which has not been found by other surface probes, e.g., AES, EELS, etc, corresponding to the formation of an elementary dipole layer. During this phase the Increase In the effective electron affinity with oxygen uptake achieves a maximum of 1V at 0.3 monolayer (ML), on SI(111) at 300 K. We report, for the first time, SPV spectra of SI(111), at 100 K, indicating quenching of a band of surface states centered around the fermi-level, quenching Is completed at the max-Imum of the work function change.The second adsorption phase, involving oxygen penetration through the surface layer and incorporation Into the lattice, commences at 0.25 ML for Si(111) at 300 K. a much earlier stage than previously reported. Further. we find evidence of a metastable SiO2 precursor at coverages below 1 ML. The dipole layer formation (and breakup) is shown to be very sensitive to both temperature and amount of surface Carbon contamination. The second phase also Involves a substantial reduction In band-bending to nearly flat bands at 2 ML, accounting for 20% of the work function change In the case of SI and almost 90% for Ge.
Unified Model for Ballistic Transport and Gas-Solid Reactions in Features
Authors: Cale T. S. , Raupp G. B. , Gandy T. H. 
Published: March 2011

ABSTRACTThe three dimensional equations which govern free molecular or ballistic transport and heterogeneous gas-solid reactions in features on patterned wafers during low pressure processing are reviewed. The governing equations specific to long rectangular trenches are extended to include nonuniform molecular velocity distributions in the source volume above the wafer as well as surface diffusion of adsorbed species or intermediates. Introduction of reaction stoichiometries and kinetic expressions for general deposition and etch reactions completes the specification of the problem. Local generalized sticking factors arise in the process of nondimensionalizing the governing equations.
Metal-Organic Chemical Vapor Deposition of Aluminum from Trialkylamine Alanes
Authors: Gross M.E. , Dubois L.H. , Nuzzo R.G. , Cheung K.P. 
Published: March 2011

ABSTRACTTrialkylamine alanes are attractive precursors for the metal-organic chemical vapor deposition (MOCVD) of aluminum thin films in microelectronics applications. The weak Al-N interaction and the absence of Al-C bonds (which decompose by highly activated processes) make these compounds excellent alternatives to the most widely studied Al CVD precursor, triisobutyl aluminum (TIBA). Solid trimethylamine alane (TMAA) and liquid triethylamine alane (TEAA) have vapor pressures at room temperature of 1 and 0.5 torr, respectively. In addition, these compounds are stable, non-pyrophoric, and are easily prepared. We report parallel studies of Al CVD in a low pressure, cold wall reactor and in an ultrahigh vacuum chamber to understand both the surface chemistry and the growth morphology. These studies, in turn, are compared with the decomposition chemistry and MOCVD characteristics of TIBA.
Surface Reactions in the Decomposition of Zinc Alkyls on Si(100)-2×1 Surfaces
Authors: Rueter M.A. , Vohs J.M. 
Published: March 2011

ABSTRACTThe adsorption and reaction of dimethylzinc and diethylzinc on Si(100)-2×l surfaces was studied using temperature programmed desorption and high resolution electron energy loss spectroscopy. These zinc alkyls were found to dissociate at temperatures less than 300 K to produce adsorbed alkyl species and deposit zinc on the surface. During temperature programmed desorption zinc metal desorbed at 530 K leaving only alkyl species on the surface at higher temperatures. Surface methyl groups were found to decompose to carbon and hydrogen or desorb as methyl radicals, while surface ethyl groups underwent a series of surface reactions which resulted in three separate ethylene desorption peaks. The results of this study provide new insight into the reactions of group II metal alkyls on silicon surfaces.
Blanket Tungsten Film Evaluation for Application to Submicron Contact Filling
Authors: Charneski Lawrence J. , Ha Chang L. , Matsuda Kenzo , Sakiyama Keizo 
Published: March 2011

ABSTRACTThe ptanarization of metal interconnect Layers has recently been a subject of intensive development effort in semiconductor processing. Although layer thicknesses have not decreased In proportion, lateral dimensions have been reduced to the point that aspect ratios are too large for effective step coverage by conventional film deposition techniques. The most difficult structure to peanarize is submicron contact holes in thick dielectrics.A dual-Layer CVD blanket tungsten film was shown to be viable for use as an interconnect material in submicron processes. A single-wafer reactor operating at a pressure of 80 Torr was used to deposit the film. The film exhibits superior properties in terms of its basic characteristics. The film completely fits submicron contacts to silicon, yet has a low surface roughness that would minimize concomitant photolithography and etching problems. Film adhesion is excellent, uniformity and reproducibility are >95%, depgsition rate is greater than 400 nm/mmn., stress is below 8×109 dynes/cm2, and resistivity is 11 μ-ohm-cm or less.
Excimer Laser-Induced Surface Activation of Aln for Electroless Metal Deposition
Authors: Esrom Hilmar 
Published: March 2011

ABSTRACTA new method for selective metal deposition on aluminum nitride (AIN) is presented. Excimer laser radiation is used for local decomposition of AIN in air. The degree of the surface modification depends on the fluence and number of pulses. A distinct wavelength dependence of the threshold fluence decomposition of AIN was found. The irradiated surface regions act as catalysts in conventional electroless metal plating baths. Structured metal coatings of various elements (Cu, Ni, Au, Pd, etc.) on AIN can thus be obtained in a simple way.
Chemistry of SiO2 Plasma Deposition
Authors: Smith Donald L. , Alimonda Andrew S. , Chuang Tzu-Chin 
Published: March 2011

ABSTRACTThe chemistry of SiO2 deposition from N20-SiH4 plasma was studied by line-ofsight mass spectrometry coupled with film analysis. If rf power and N2O flow are sufficient, more than enough O atoms are available to convert all of the SiH4 to SiO2, and good electrical characteristics (IV and breakdown) are then obtained with or without He dilution. Gas-phase SimHn(OH)p species make a minor contribution to the deposition and may be the source of the OH in the film. Both [OH] and electron trapping are much larger than for thermal oxide, with or without He dilution.
Laser Studies of the Interaction of SiO with the Surface of a Thin Film
Authors: Ho Pauline , Buss Richard J. , Weber M. E. 
Published: March 2011

ABSTRACTThe interaction of SiO radicals from a SiCl4/O2 plasma with the surface of a depositing thin film is studied with the IRIS (Imaging of Radicals Interacting with Surfaces) technique, which combines spatially-resolved laser-induced fluorescence with molecular beam methods. In contrast to previous results for SiH, SiO appears not to react at the surface of the depositing film, but desorbs with a cosine spatial distribution for a wide range of substrate temperatures. No evidence is observed for specular scattering of the molecules.
Electrical and Chemical Characterization of SiO2 Deposited by Electron Cyclotron Resonance - PECVD.
Authors: Andosca R.G. , Varhue W.J. , Titcomb S. 
Published: March 2011

ABSTRACTThin films of silicon dioxide were deposited on (100) Si at low temperatures (room temperature to 375 °C). Oxygen was introduced into the resonance chamber while a dilute silane gas mixture (2% in helium) was fed to a gas ring supported 10 cm above the wafer. Index of refraction, deposition rates, etch rates (for buffered HF), dielectric constant, and oxide breakdown strength were determined as a function of substrate temperature and RF substrate bias. Hydrogen content and Si-O bonding were measured by FTIR spectroscopy. All properties are reported in terms relative to thermally grown oxide.Film properties improved with increasing substrate temperature and RF substrate bias, sometimes equaling that of thermal oxide. Film quality was the highest for samples deposited at 375 °C, with an applied RF substrate bias.
Mechanism of Plasma-Enhanced Deposition of Silicon Dioxide from Teos/O2 Mixtures
Authors: Raupp Gregory B. , Cale Timothy S. , Peter H. , Hey W. 
Published: March 2011

ABSTRACTThe deposition rate of silicon dioxide from TEOS/02 capacitively-coupled plasmas increases with increasing applied rf power, increasing total pressure and decreasing wafer temperature. These dependences can be explained by a mechanism in which deposition occurs through both an ionassisted and an oxygen atom initiated pathway. The ion-induced deposition rate increases with increasing rf power density and decreasing total pressure, and is independent of wafer temperature. Assuming a well-mixed plasma, and using literature values for reaction rate parameters and rate forms for oxygen plasma reactions, the rate of atom-induced deposition was found to be independent of temperature and TEOS concentration and directly proportional to oxygen atom concentration. The model suggests that the apparent negative activation energy for deposition results from competition between deposition and thermally-activated atomic oxygen surface recombination. The derived deposition rate form is consistent with an Eley-Rideal mechanism in which the rate determining step for film deposition is oxidative attack of adsorbed TEOS or TEOS fragments by a activated oxygen.
Diethylsilane as a Silicon Source for the Deposition of Silicon Nitride and Silicon Oxynitride Films by LPCVD
Authors: Hochberg Arthur K. , O'Meara David L. 
Published: March 2011

ABSTRACTA purified diethylsilane (DES), LTO-410TM, has been studied as a silicon precursor for the deposition of silicon nitride and silicon oxynitride films by LPCVD. In the temperature range from 650 to 725°C mixtures of DES and NH3 produce uniform, oxidation resistant silicon nitride layers. Auger and RBS analyses show that the carbon concentrations in the films are correlated with the DES partial pressures. The film refractive indices also correlate with the carbon levels in the films for a fixed deposition temperature. Mixtures of DES, NH3, and N2O deposit silicon oxynitride films in the temperature range from 650 to 700°C with compositions controlled by the NH3:N2O ratio for a fixed DES flow. These films have carbon levels below the minimum detectable limit of Auger and RBS analyses.
Modelling of Mechanisms Involved in Ceramic Synthesis by Laser Conversion of an Organosilazane Aerosol
Authors: Strutt Peter R. , Xiao Tongsan D. , Gonsalves Kenneth E. , Klemens Paul G. 
Published: March 2011

ABSTRACTA study has been made of basic mechanisms involved in a new process for the rapid synthesis of preceramic nanoparticle powders. In this process an aerosol, formed from an ultrasonically atomized liquid organosilazane monomer, (CH3SiHNH)n with n = 3 or 4, is injected into the beam of an industrial cw CO2 laser. One critical feature examined is the rapid condensation of molecular species from the laser plume, in a process involving 3-dimensional cross-linking. In accompanying studies, a model has been formulated to determine the laser plume temperature, the cooling rate of condensing species, and the particle diameter. These are obtained by analytical solution of heat conduction, momentum and mass conservation equations that consider heat loss, by gas conduction, radiation, evaporation, and convection.
Epitaxial Growth of Ferroelectric Pb(Mgl/3Nb2/3)03 Film by Sol-Gel Method
Authors: Okuwada Kumi , Nakamura Shin-Ichi , Imai Motomasa , Kakuno Keiichi 
Published: March 2011

ABSTRACTFerroelectric thin films, which are Pb(Mgl/3Nb2/3)03 (PMN) and Pb(Mgl/3Nb2/3)03 - PbTiO3 (PMN-PT) in the perovskite phase, were obtained by the sol-gel method with metal alkoxides. The films had highly preferred orientation on substrates whose interplanar spacings are close to that for the perovskite structures in PMN and PMN-PT. Epitaxial growth process in PMN film was investigated.
Single Source Precursors for III-V OMCVD Growth and Pyrolysis Studies
Authors: Jones Richard A. , Cowley Alan H. , Ekerdt John G. 
Published: March 2011

ABSTRACTCompounds of the type (L2MEL'2)x, where M and E are the group III and V elements, respectively, and L and L' are ligands which may be thermally eliminated are being studied as single source precursors to III-V semiconductors. An array of these compounds have been synthesized with various III-V combinations, and hydride and alkyl ligands. Film growth was studied over the temperature range of 450-600 °C and at 10−4 Torr. Growth rates of 1 μm/hr are typical when the compounds are maintained at 125-140 °C. (Me2Ga(μ-t-Bu2As) [2 led to films which were polygrained with the grains oriented in the (111) direction and retained the 1:1 stoichiometry of the precursor. Films from [Me2Ga(μ-i-Pr2As)]3 did not retain the 1:1 stoichiometry and did not show the preference for (111)- oriented growth.
A Small Angle Neutron Scattering Investigation of the Kinetics of Phase Separation in an Fe-27.5 AT.% Cr-5.6 AT.% Ni Alloy
Authors: Epperson J. E. , Rainey V. S. , Windsor C. G. , Hawick K. A. , Chen Haydn 
Published: March 2011

AbstractThe small angle neutron scattering has been investigated in situ at 450° and 500°C for a polycrystalline, duplex Fe-27.5 at.% Cr - 5.6 at.% Ni steel. A broad diffuse maximum in the scattering function is the signature of the α' phase formation, and this maximum is superimposed on a strong, temperature-dependent component due mainly to critical magnetic scattering. The time dependence of the shift in the peak intensity position to lower scattering vectors and the increase in peak intensity obey power law scaling behavior. Furthermore, the structure function exhibits dynamical scaling, after about three hours annealing. It is suggested that this behavior could be utilized to predict the microstructure, and hence some of the properties, after significantly longer annealing times.