bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidation Kinetics of Silicon Surfaces: Reactive Sticking Coefficient, Apparent Saturation Coverage and Effect of Surface Hydrogen
Authors: George S. M. , Gupta P. , Mak C. H. , Coon P. A. 
Published: March 2011

ABSTRACTThe kinetics of the initial oxidation of silicon surfaces by O2 were studied using laser-induced thermal desorption (LITD), temperature programmed desorption (TPD) and Fourier Transform Infrared (FTIR) spectroscopy. The LITD results showed that the oxidation of Si(111)7×7 by O2 was characterized by two kinetic processes: an initial rapid oxygen uptake followed by a slower growth that asymptotically approached an apparent saturation oxygen coverage. The initial reactive sticking coefficient of O2 on Si(111)7×7 decreased with surface temperature. In contrast, TPD experiments on Si(111)7×7 and FTIR studies on porous silicon demonstrated that the apparent saturation oxygen coverage increased as a function of surface temperature. Experiments with preadsorbed hydrogen also revealed that silicon oxidation was inhibited as a function of increasing hydrogen coverage on the Si(111)7×7 surface.
Infrared Spectroscopy of Si(111) and Si(100) Surfaces After HF Treatment: Hydrogen Termination and Surface Morphology
Authors: Chabal Y. J. , Higashi G. S. , Raghavachari K. 
Published: March 2011

ABSTRACTThe methodology for extracting structural information from surface infrared spectra is exemplified by considering the silicon-hydrogen stretching modes of flat and vicinal Si(111) and Si(100) surfaces obtained after HF treatment.
Surface Condition in the Plasma-CVD of a-Si:H,F from SiF4 and H2
Authors: Maruyama A. , Shen D. S. , Chu V. , Liu J. Z. , Jaroker J. , Campbell I. , Fauchet P. M. , Wagner S. 
Published: March 2011

ABSTRACTWe present a detailed study of the growth of a-Si:H,F from SiF4 and H4. The growth surface appears to have a high density of surface states. These surface states can be thermally relaxed by keeping the films at growth temperature after the termination of growth, suggesting that the states were created during film growth. When frozen in, the surface state density is found to depend on the conditions during film growth. The density is related to the sharpness of the valence band tail as measured by the Urbach Energy. We believe that a reaction on the growth surface resulting in fluorine elimination creates these surface states and also affects the formation of the Si-network.
Kinetic and X-ray Photoelectron Spectroscopic Studies of the Thermal Nitridation of Si(100)
Authors: Peden C. H. F. , Rogers J. W. , Blair D. S. , Nelson G. C. 
Published: March 2011

ABSTRACTThe thermal nitridation of Si(100) by NH3 and N2H4 has been studied by X-ray photoelectron (XPS) and Auger electron (AES) spectroscopies. The pressure dependence of the rates as a function of reaction time has been measured. It has been found that the growth of the first monolayer (ML) of nitride is mediated by a surface reaction step. For subsequent growth, diffusion of one or more of the reacting species becomes an important process in determining the rate of reaction. Such species may be substrate Si diffusing to the vacuum/Si3N4 interface, or possibly network nitrogen diffusing into the Si substrate. The independence of the reaction rate on NH3 or N2H4 pressure at long reaction times rules out a mechanism involving molecular diffusion of the nitriding gas to the Si3N4/Si interface in a manner similar to the oxidation of Si by O2 or H2O. Careful analysis of the Si(2p) XPS spectra reveals the presence of a unique Si species with a Si(2p) binding energy intermediate between elemental Si and Si in Si3N4. Further, the relative intensity of the Si(2p) features due to this species, and the angular dependence of the XPS peaks indicate that they result from a ML of Si at the outermost surface layer, on top of the growing Si3N4 film.
Laser Studies of the SiH Radical/Surface Interaction During Deposition of a thin Film
Authors: Ho Pauline , Buss Richard J. , Breiland William G. 
Published: March 2011

ABSTRACTThis paper presents a new method for studying the interaction of radicals with the surface of a depositing film using a combination of laser spectroscopy and molecular beam techniques. The reactivity of SiH molecules with the surface of a depositing a-Si:H film is measured to be at least 0.95, with no strong dependence on rotational state.
Dependence of PECVD Silicon Oxynitride Properties on Deposition Parameters
Authors: Helms Aubrey L. , Havrilla Robert M. 
Published: March 2011

ABSTRACTThe properties of Plasma Enhanced Chemical Vapor Deposited (PECVD) silicon oxynitride thin films were determined for a variety of deposition conditions. The films were characterized with respect to stress, refractive index, deposition rate, hydrogen content, dielectric constant, and uniformity. The films were deposited in an Electrotech ND6200 parallel plate reactor using a silane - ammonia - nitrous oxide process gas chemistry. Deposition parameters which were investigated include process gas flow rate, power, and total pressure. The possible application of these films as both inter-layer and final passivation layers for use on GaAs ICs will be discussed.
The Effects of Surface Treatments for Low Temperature Silicon Dioxide Deposition on Cadmium Telluride.
Authors: Choi Seong S. , Kim S. S. , Tsu D. V. , Lucovsky G. 
Published: March 2011

ABSTRACTWe have successfully deposited thin films of SiO2 on a cadmium telluride substrate at low temperature (Ts =100°C–300°C) by remote plasma enhanced chemical vapor deposition (Remote PECVD). The native oxide on the CdTe substrate has been removed, prior to deposition by either chemical etching in methanol and 1% bromine, or by dissolution in deionized water. After removal of the native oxide, the CdTe was inserted into a UHV-compatible deposition chamber and a He+ plasma treatment was performed prior to deposition of an SiO2 film. This treatment promotes strong adhesion between the deposited SiO2 film and the CdTe surface. We find that the initial oxide removal process does not influence SiO2 adhesion. The effect of the He+ plasma treatment on the CdTe surface has been studied by Auger electron spectroscopy(AES), and Reflection high energy electron diffraction (RHEED).
Controlled Mass Flow of Low Volatility Liquid Source Materials
Authors: Nolet Alan D. , Rhine Bruce C. , Logan Mark A. , Wright Lloyd , Monkowski Joseph R. 
Published: March 2011

ABSTRACTChemical Vapor Deposition (CVD) of thin films for microelectronic devices has historically used source materials that are gases at room temperature [1]. The decision to use gases was largely a practical one based on the relative ease with which the flow of gaseous materials can be controlled. CVD of thin films plays a vital role in increased circuit density and performance of integrated circuits. Liquid sources offer alternative source composition, reaction kinetics and reaction mechanisms to optimize a given CVD process [2].For example, CVD films of silicon dioxide (oxide) and oxide films modified to lower the glass transition temperature such a borophosphosilicate glass (BPSG) have traditionally used gaseous source materials such as silane, diborane and phosphine [3]. An all liquid system of tetraethylorthosilicate (TEOS), triethylborate (TEB) and triethylphosphine (TEPhine) has been found to offer superior conformality and overall safety [4]. However, from a practical standpoint, the all liquid system has historically suffered from reliable, reproducible mass flow control.
Aluminum Chemical Vapor Deposition Using Triisobutylaluminum: Mechanism, Kinetics, and Deposition Rates at Steady State
Authors: Bent Brian E. , Dubois Lawrence , Nuzzo Ralph G. 
Published: March 2011

ABSTRACTAn important step in the chemical vapor deposition (CVD) of aluminum from triisobutylaluminum (TIBA) is the reaction between TIBA (adsorbed from the gas phase) and the growing aluminum surface. We have studied this chemistry by impinging TIBA under collisionless conditions in an ultra-high vacuum system onto single crystal Al(111) and Al(100) substrates. We find that when TIBA (340K) collides with an aluminum surface heated to between 500 and 600K, the aluminum atom is cleanly abstracted from this precursor with near unit reaction probability to deposit, epitaxially, carbon-free aluminum films. The gas phase products are isobutylene and hydrogen. From monolayer thermal desorption experiments, we have determined the kinetic parameters for the rate-determining step, a β-hydride elimination reaction by surface bound isobutyl ligands. Using these kinetic parameters and a Langmuir absorption model, we can predict the rate of aluminum deposition at pressures ranging from 10−6 to 1 Torr.
Epitaxial Growth of Al on Si By Gas-Temperature-Controlled CVD
Authors: Kobayashi Tsukasa , Sekiguchi Atsushi , Hosokawa Naokichi , Asamaki Tatsuo 
Published: March 2011

ABSTRACTEpitaxial Al(111) film was deposited on Si(lll) by low-pressure chemical vapor deposition with the use of tri-isobutyl aluminum (TIBA) at the substrate temperature of 400 °C with the deposition rate of 0.9 μm/min. It was necessary for epitaxy to preheat the TIBA gas just before the deposition on the substrate. The preheat was made by gas-temperature-controller provided in the chamber. The film surface was so smooth that reflectance was higher than 90 % of Si and 20 ppm of O, C, and H. No hillock appeared on the film after 430 °C annealing for 40 min. The interface of Al and Si was rather stable so that no alloy penetration occured. The possibility of epitaxial growth of Al(100) on Si(100) was also shown.
Excimer Laser Photofragmentation of TMA on Aluminum: Identification of Photoproduct Desorption Dynamics
Authors: Orlowski T. E. , Mantell D. A. 
Published: March 2011

ABSTRACTNew mechanistic details regarding aluminum deposition by ArF excimer laser photodecomposition of trimethylaluminum (TMA) adsorbed on aluminum covered SiO 2/Si substrates have been obtained using a time-of-flight quadrupole mass spectrometer. CH3 radicals and Al-(CH3)n (n = 1,2,3) species are efficiently photoejected from the surface with up to 0.22 eV of translational energy. Experiments at various TMA dosing levels reveal differences in desorbed fragment translational energy presumably associated with variations in surface site binding energy. No direct evidence is found for desorption of A1 from the surface indicating that A1 is more tightly bound than methyl-aluminum fragments. By carefully monitoring changes in fragment translational energy as an A1 deposit forms on the clean SiO2/Si substrate, we examine how the surface influences the onset of A1 growth. No evidence of ethane or methane desorption from the sample surface is found implying that radical recombination and hydrogen abstraction are primarily secondary gas phase reactions which are not surface initiated.
Syntheses of Metal Chalcogenides Using Organometallic Methods
Authors: Steigerwald Michael L. 
Published: March 2011

ABSTRACTThe precursor method is being used increasingly in the preparation of solid state inorganic materials. Use of this general method allows the isolation of otherwise inaccessible phases and the preparation of known phases under much milder conditions. One approach which holds promise is the use of organometallic precursors for the preparation of both thin films and bulk samples of inorganic materials. In this paper I describe our syntheses of several metal chalcogenides from organometallic reagents.
The Effect of Metal Atoms and Ligand Combinations in Organometallics on Excimer Laser Photoproducts and Yields
Authors: Zhang Y. , Stuke M. 
Published: March 2011

ABSTRACTA systematic study to find the role of different metal atoms and ligand combinations on the yield of the photoproducts generated upon irradiation of gas phase organometallics (i.e. metalalkyls) by uv excimer laser radiation was performed using laser ionization mass spectrometry.
Chemical Vapor Deposition of Cobalt Silicide
Authors: West Gary A. , Beeson Karl W. 
Published: March 2011

ABSTRACTCobalt silicide films have been deposited by chemical vapor deposition using Co2(CO)8or HCo(CO)4as the Co source and SiH4or Si2H6as the Si source. The Co:Si ratio of the films increases with the deposition temperature, and CoSi2stoichiometry is obtained at 300° C using SiH4or at 225° C when Si2H6is the Si precursor. Resistivities of films deposited in the range CoSi2.0to CoSi3.0. are typically 200 microohm-cm and drop to 30 – 40 microohm-cm upon annealing at 900° C.
Low-Temperature Organometallic Chemical Vapor Deposition of Transition Metals
Authors: Kaesz Herbert D. , Williams R. Stanley , Hicks Robert F. , Chen Yea-Jer Arthur , Xue Ziling , Xu Daqiang , Shuh David K. , Thridandamt Hareesh 
Published: March 2011

ABSTRACTA variety of transition-metal films have been grown by organometallic chemical vapor deposition (OMCVD) at low temperatures using hydrocarbon or hydrido-carbonyl metal complexes as precursors. The vapors of the metal complexes are transported with argon as the carrier gas, adding H2 to the stream shortly before contact with a heated substrate.High-purity platinum films have been grown using (η5−C5H5)PtMe3 [1] or (η5−CH3C5H4)PtMe3 [2] at substrate temperatures of 180°C or 120°C, respectively. The incorporation of a methyl substituent on the cyclopentadienyl ligand decreases the melting point of the organoplatinum complex from 106°C [1] to 30°C [2] and increases the vapor pressure substantially. Film deposition also occurs at a lower substrate temperature. Analyses by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) indicate that the films are well crystallized and do not contain any observable impurities after sputter cleaning.The substrate temperatures for the first appearance of other transition-metal films from organometallic precursors are as follows (°C): Rh(η3−C3H5)3 (120/Si), Ir(η3-C3H5)3 (100/Si), HRe(CO)5 (130/Si) and Ni(η5−CH3C5H4)2 (190/glass, 280/Si). These films are essentially amorphous and contain trace oxygen impurities (< 2%), except for the Re film, which was 10% oxygen and 20%carbon.
The Deposition of Metallic and Non-Metallic Thin Films Through the Use of Boron Clusters.
Authors: Zhang Zhongju , Kim Yoon-Gi , Dowben P. A. , Spencer James T. 
Published: March 2011

ABSTRACTNew borane clusters and their corresponding transition and rare earth metal complexes are currently being investigated in our laboratories for their utility as unique source materials for the formation of both metallic and non-metallic thin films. These borane cluster complexes exhibit highly favorable properties for use in OMVPE processes, such as; (1) relatively high volatility, (2) anticipated high stability of the ligand itself to provide clean ligand-metal dissociations, (3) high temperature stabilities of the complexes, (4) readily preparable in significant quantities, and (5) availability of theoretical and spectroscopic probes of structure-reactivity relationships. In this work, we have prepared both non-metallic thin films, including materials such as boron nitride, and metallic thin films (both the transition and rare earth metals) through the use of these unique cluster materials.Boron nitride has been investigated as a potential hard coating for use as an insulating electrical layer and protective coating. We have investigated plasma enhanced chemical vapor deposition and pyrolytic deposition of boron nitride from readily available and easily handled borane clusters. Auger electron spectroscopy was used to show that the film was high purity boron nitride of uniform composition.The deposition of transition and rare earth metal thin-film materials of controlled stoichiometry has recently received considerable interest. We have discovered the borane cluster-assisted deposition (CAD) of metallic thin-films involving both transition and rare earth metal materials. Through the use of this unprecedented borane cluster chemical transport process, films ranging in thickness from 100 nm to several microns have been straightforwardly and systematically prepared for numerous metal and mixed-metal boroncontaining systems with controlled composition at relatively low temperatures. These new materials have been characterized by SEM and other techniques.
Polyalkylsilynes: Synthesis and Properties of “Two-Dimensional” Silicon-Silicon Bonded Network Polymers.
Authors: Biancon Patricia A. , Weidman Timothy W. , Schilling Frederic C. 
Published: March 2011

ABSTRACTThe synthesis of the first soluble silicon-silicon bonded network polymers, the polyalkylsilynes [RSi]n was accomplished using high-intensity ultrasound to effect the reductive condensation of alkyltrichlorosilanes with liquid sodium-potassium alloy. The resulting polymers remain hydrocarbon-soluble and may be cast into transparent films. Spectroscopic data indicate a structure consisting of tetrahedral alkylsilicon units assembled via silicon-silicon bonds into amorphous networks. Films or solutions of the polysilynes exhibit an intense UV absorption which tails into the visible, blue-shifted but similar in shape and intensity to that of amorphous silicon. The photoreactivity and pyrolysis properties of these materials will be described.
New Precursors for the Organometallic Chemical Vapor Deposition of Aluminum Nitride
Authors: Gladfelter Wayne L. , Boyd David C. , Hwang Jen-WeI , Haasch Richard T. , Evans John F. , Ho Kwok-Lun , Jensen Klavs F. 
Published: March 2011

ABSTRACTOrganometallic aluminum azides have been found to be effective precursors for the low temperature chemical vapor deposition of thin films of aluminum nitride. Quantitative analysis of the gas phase products of the reaction are used to develop an understanding of the reaction. Rate studies of the deposition were performed in the temperature range from 400 to 800°C. Below 525°C, an activation barrier of 26.4 kcal/mol was found, while above 525°C, a value of 5.23 kcal/mol was obtained. The effects of the presence of N-C bonds and the type of Al-N interaction within the precursor are evaluated.
The Use of Tris(Trimethylsilyl)Arsine to Prepare AlAs, GaAs and InAs. The X-Ray Crystal Structure of (Me3Si)3AsAlCl3.C7H8.
Authors: Wells Richard L. , Pitt Colin G. , Mcphail Andrew T. , Purdy Andrew P. , Shafieezad Soheila , Hallock. Robert B. 
Published: March 2011

ABSTRACTThe reactions of (Me3Si)3As with group III halides have been utilized to prepare AlAs, GaAs and InAs. The adduct (Me3Si)3AsAlCl3 has been isolated as an intermediate in the formation of AlAs from (Me3Si)3As and AICI3. The crystal structure of its toluene solvate has been determined.
Adhesion of Metals to Mixed Oxide Coatings (Al & Cr, Mo, OR W) Prepared by Spray Pyrolysis of Organometallics.
Authors: Burlitch James M. , Demott Gerard J. , Kohlstedt David L. 
Published: March 2011

ABSTRACTSpray pyrolysis of the mixed metal organometallics, Al[M(CO)3C5H5]3 (M is Cr, Mo or W), prepared in tetrahydrofuran from the mercury analogues and aluminum metal, gave mixed oxide gels on heated alumina substrates. Air was used as the propellant for M = Cr, whereas oxygen was used for M = Mo or W. Mixtures of Al[Cr(CO)3C5 H5]3 and Al(O-i-C3H8)3 having a Cr/Al ratio of 0.02 to 0.93 were used to prepare gels with intermediate dopant concentrations. When calcined at 500 °C, the gels produced amorphous coatings of two-component oxides that were characterized by SEM and EDS methods. The strength of adhesion of a E-beam evaporated chromium metal overlayer to the coating, as measured by a continuous microindentation method, increased in the order Cr < Mo ≅ W; adhesion was found to be directly proportional to the effective free energy of formation of the oxide mixture.
Surface Reactions Leading to Contamination of Metal Films Photochemically Deposited from the Hexacarbonyls
Authors: Singmaster K. A. , Houle F. A. , Wilson R. J. 
Published: March 2011

ABSTRACTA systematic study of the origin of contaminants in metal films photochemically deposited from the group VI hexacarbonyls is described. Background gas present in the cell during deposition, exposure to air and incomplctc removal of CO groups from the surface of the growing film all affect C and O incorporation. The data are compared to results of recent experiments examining surface photoproducts of the metal carbonyls.
Molecular Beam Study of the KrF* Laser Photodissociation of Cr(CO)6 and Mo(CO)6
Authors: Tyndall George W. , Jackson Robert L. 
Published: March 2011

ABSTRACTThe one-photon and sequential two-photon KrF* laser (248 nm) photodissociation of Cr(CO)6 and Mo(CO)6 were studied in a molecular beam using mass spectrometry to detect the photoproduct molecular ions. For Cr(CO)6, the major one-photon product, Cr(CO)4, undergoes secondary photodissociation to give predominantly Cr(CO)2. The photodissociation cross section of Cr(CO)4 is found to be 1.6 × higher than that of Cr(CO)6 at 248 nm. For Mo(CO)6, the major one-photon products, Mo(CO)5 and Mo(CO)4, undergo secondary photodissociation to give predominantly Mo(CO)3.
The Direct Photo-CVD of Silicon Dioxide from Si2H6 and N2O3
Authors: Bhatnagar Yashraj K. , Milne W. I. 
Published: March 2011

ABSTRACTThe direct photo-CVD of silicon dioxide on c-Si substrates has been achieved using a new combination of Si2H6 and N2O3 gases, with an external deuterium lamp as the VUV source. The variation of the deposition rate and the refractive index with process parameters is reported. FTIR studies on these oxides show that the oxide is very nearly stoichiometric with no Si-N bonds and only trace amounts of Si-H bonds. C-V, I-V and breakdown measurements made on these films are reported. a-Si:H thin film transistors have also been fabricated using this oxide as the gate dielectric.
Pyrolytic and Laser Photolytic Growth of Crystalline and Amorphous Germanium Films from Digermane (Ge2H6)
Authors: Eres Djula , Lowndes D. H. , Tischler J. Z. , Sharp J. W. , Geohegan D. B. , Pennycook S. J. 
Published: March 2011

ABSTRACTHigh-purity digermane (Ge2H6, 5% in He) has been used to grow epitaxially oriented crystalline Ge films by pyrolysis. Amorphous Ge:H films also have been deposited by pyrolysis and ArF (193 nm) laser-induced photolysis. The amorphous-to-crystalline transition and the film's morphology was studied as a function of deposition conditions. The film's microstructure, strain and epitaxial quality were assessed using x-ray diffraction curves and scanning and transmission electron microscopy. It was found that commensurate, coherently strained epitaxial Ge films could be grown pyrolytically on (100) GaAs at low (0.05–40 m Torr) Ge2H6 partial pressures, for substrate temperatures above 380°C.
Hydrogen Ion Beam Smoothening of Oxygen Roughened Ge(001) Surfaces
Authors: Horn K. M. , Chason E. , Tsao J. Y. , Picraux S. T. 
Published: March 2011

ABSTRACTA smooth Ge(001) surface can be severely roughened by chemical etching with oxygen gas and then returned to its original smoothness by exposure to hydrogen. The rate of recovery of the surface depends strongly on temperature, as well as on whether the hydrogen is introduced as a low energy ion beam or simply as a gas. The roughness induced in the surface by etching is “locked-in” after removal of the oxygen gas through pinning of ledges by residual contamination. This pinning prevents the surface from smoothening thermally. The introduction of hydrogen to the surface promotes a chemical reaction which frees the pinned sites and allows thermal smoothening to proceed.