bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactive Deposition of a-Silicon and Si-Based Alloys
Authors: Hanna J. , Oda S. , Shibata H. , Shirai H. , Miyauchi A. , Tanabe A. , Fukuda K. , Ohtoshi T. , Tokuhiro O. , Nguyen H. , Shimizu I. 
Published: March 2011

ABSTRACTHigh photoconductive a-Si:H(F) and St-based alloys were prepared from “precursors” made by oxidation of silane with F2 or reduction of SiFn (n=1,2,) with atomic hydrogen. Both crystalline and amorphous silicon were prepared at will, in the latter case, by controlling the flow of hydrogen. A marked reduction in the localized states in the vicinity of valence band was eatablished in the a-Si:H(F) prepared under optimal condition. A novel photoconductive film with high photoconductive gain for near-tr light was successfully made by multiplying a-Si:H/a-SiGe:H(F) periodically by a new preparation technique without a rise in the dark conductivity.
Wafer Characterization of an Epi Reactor Using Sheet Resistance Mapping
Authors: Johnson Walter H. , Keenan W. Andrew , Smith Alan K. 
Published: March 2011

AbstractSheet resistance mapping has become an indispensable tool in characterizing ion implanters for both integrated circuit manufacturers and equipment manufacturers. The sheet resistance mapping technique is now being extended into additional applications such as the characterization of metal deposition, CVD, and epitaxial silicon growth. This technique has become especially necessary with the advent of 150mm and 200mm wafers, where 5 or 9 site measurements cannot provide sufficient data essential for process control.In order to optimize the performance of an epi reactor it is necessary to control and characterize the gas flows and temperature distributions inside the reactor. The control of these variables is essential for thickness and resistivity uniformity in epi layers. This paper describes the use of sheet resistance profiles and contour maps to study the resistivity and thickness uniformity variations in an epi reactor. The sheet resistance maps allow for control of the epi process without requiring data from other test sources.This ensures real time process control for production, as well as very rapid feedback for maintenance while doing equipment repair.
Defects Characterization of Arsenic Implanted Silicon by Ac Hall Effect Measurements
Authors: Jaouen H. , Ghibaudo G. , Christofides C. 
Published: March 2011

AbstractAC and DC Hall effects measurements as a function of temperature (77-300K) and frequency ( 1Hz-100KHz) have been performed to characterize Implanted Silicon films. This technique enables the determination of the annihilation processes of defects In such layers as a function of temperature of isochronal anneallngs (300°C to 1100°C during 1 hour). The experimental results are discussed with respect to proper transport models based on short and long range disorder considerations in order to find out the features of defects and Inhomogeneities arising from implantation and their thermal annihilation after isochronal annealing.
The Formation of Highly Conductive Shallow Junction Layers in (100) Siliconl By Gallium Ion Implantation
Authors: Harrison H.B. , Li Y.H. , Sai-Halasz G.A. , Iyer S. 
Published: March 2011

AbstractThis paper presents the results obtained from a comparative study of ion implanted Gallium (Ga) into (100), n type Silicon. A comparison is made between long time (≥ 30 mins) furnace annealed and Rapid Thermally Processed (RTP), 100keV implants of 1 and 3×10l5/cm2 doses of Ga. The results show that for RTP an extremely high substitutional concentration of Gallium, in excess of 3×1020/cm3 can be obtained with approximately 100% electrical activation, resulting in highly conductive very shallow p type layers.
Silicon Transport in Lateral Silicide Growth of CrSi2
Authors: Zheng L. R. , Doolittle L. R. , Mayer J. W. 
Published: March 2011

AbstractSilicide formation and growth are studied in three geometries: conventional planar thin films, lateral diffusion couples formed by depositing metal layers on Si islands, and device geometry couples formed by depositing metal on oxide-patterned Si substrates. The influence of impurities is studied by implanting arsenic and krypton into conventional and device geometry structures.Here we present growth kinetics of CrSi2 where the presence of impurities has a strong influence. Si transport dominates in disilicide formation and leads to erosion of contacts around the periphery of oxide windows. Implantation of arsenic suppresses CrSi 2 formation; with krypton implantation, the growth kinetics shifts from linear to square-root in character. We attribute these results to impurity segregation at interfaces or grain boundaries.
Characteristics of Selective Lpcvd W Films By Silicon Reduction
Authors: Joshi R. V. , Smith D. A. 
Published: March 2011

AbstractThe characteristics of Selective LPCVD tungsten films produced by silicon reduction of tungsten hexafluoride are presented. The tungsten films deposited using Si(100), Si(111) and polysilicon undoped and doped substrates are analyzed by X-RAY, TEM, RBS, AES, SIMS and SEM. The as deposited bcc tungsten films are polycrystalline with a grain size 80 - 100Å. The effect of annealing temperature and time on the crystal structure of films was studied. Tungsten reacts to form tungsten silicide at 600°C. The silicide grain size is of the order of 100 - 200Å at 600°C and increases gradually to 400 - 500Å at 1000°C. The oxygen impurities in the film retard the silicide formation further at 1000°C. Silicon from the substrate out-diffuses to the film surface and reacts with the presence of oxygen impurities in the annealing ambient to form Si-O at 1000°C. As deposited film resistivities of 130-140 micro-ohm-cm are achieved reproducibly and reach 60-70 micro-ohm-cm after 1000°C annealing in nitrogen or argon ambient. The impurities H, C, O and F are found in the as deposited films.
Recrystallization of Oxygen Contaminated Al Films
Authors: Kolk G.J. Van Der , Verkerk M.J. 
Published: March 2011

AbstractAl was evaporated at oxygen partial pressures, PO2, varying between 10−7 and 10−4 Pa on substrates of silicon nitride. The substrate temperature was varied between 20 °C and 250°C. The films were annealed at temperatures up to 500°C.For Al films deposited at 20°C, it was found that the average grain size decreases with increasing oxygen partial pressure. After annealing recrystallization was observed. The relative increase of grain size was less for higher values of pO2. Annealing gave rise to a broad grain size distribution.For Al films deposited at 250°C, the presence of oxygen caused the growth of rough inhomogeneous films. This inhomogeneous structure remained during annealing.
Time Resolved Tem of Laser-Induced Phase Transitions in a-Ce And a-Si/Al-Films
Authors: Bostanjoglo O. , Endruschat F. E. , Tornow W. 
Published: March 2011

AbstractThis paper presents an improved new method for studying the dynamics of laser induced phase transitions down to the submicron-nanosecond scale by means of a modified commercial Transmission Electron Microscope (TEM) /1/. Results on Pulsed Laser Annealing (PLA) of amorphous Germanium and a-Si/Al films are described. Potential applications and limits of this method are briefly discussed.
Stresses in Gatelevel Interconnects of Wsi2 AND TaSi2
Authors: Townsend P. H. , Fulks R. T. , Plas H. A. Vander , Ho J. 
Published: March 2011

AbstractStresses in WSi2 films prepared by chemical vapor deposition have been examined using an optically levered laser beam during typical processing cycles to 900 C. Initial heating produces tensile stress levels of 1.0 GPa at 500 C with crystallization into the inetastable hexagonal form. Cooling from this temperature results in room temperature stresses of 1.2 GPa. A large decrease in the tensile stress level accompanies the transformation into the stable tetragonal structure during heating from 500 C to 750 C. Films in this form are mechanically stable and respond elastically to further thermal cycling.Films of TaSi2 sputtered from an intermetallic target and co-sputtered from elemental targets have also been investigated. Initial heating of films sputtered from the intermetallic target produces a tensile stress state during crystallization which is high but slightly less than observed during crystallization of WSi2. This high tensile state is not observed in films deposited in layers from elemental targets. The appearance of a metastable phase is not observed for intermediate anneals in either case. The initial crystallization results in the stable phase of hexagonal TaSi2. Fully annealed films are elastic below 920 C.
Transient Scanning Electron Beam Annealing Methods Used to Study Diffusion and Defects in Implanted Silicon
Authors: Hart Michael J. , Evans Alan G. R. , Amaratunga Gehan A. J. 
Published: March 2011

AbstractRapid thermal annealing of arsenic and boron difluoride implants, such as those used for source/drain regions in CMOS, has been carried out using a scanning electron beam annealer, as part of a study of transient diffusion effects. Three types of e-beam anneal have been performed, with peak temperatures in the range 900-1200°C; the normal isothermal e-beam anneals, together with sub-second fast anneals and ‘dual-pulse’ anneals, in which the sample undergoes an isothermal pre-anneal followed by rapid heating to the required anneal temperature in less than O.5s.The diffusion occuring during these anneal cycles has been modelled using SPS−1D, an implant and diffusion modelling program developed by one of the authors. This has been modified to incorporate simulated temperature vs. time cycles for the anneals. Results are presented applying the usual equilibrium clustering model, a transient point-defect enhancement to the diffusivity proposed recently by Fair and a new dynamic clustering model for arsenic. Good agreement with SIMS measurements is obtained using the dynamic clustering model, without recourse to a transient defect model.Defects remaining in diodes fabricated with the forementioned implants after these anneal cycles have been studied using DLTS techniques. Trap densities for the three types of e-beam anneal are comparable to those for furnace annealed diodes, as are the reverse leakage currents measured (typically 2–5nA for a 0.85mm2 diode at -5V).
XeCl Excimer Laser Annealing Used to Fabricate Poly-Si Tfts
Authors: Sameshima T. , Usui S. 
Published: March 2011

AbstractMo-gate n-channel poly-Si TFTs have been fabricated for the first time at a low processing temperature of 26°C. 500 to 1000A thick a-Si:H was successfully crystallized by pulsed XeCl excimer laser (308nm) annealing without heating the glass substrate. The channel mobility of the TFT was 180 cm2/V.sec when the a-Si:H was annealed at energy density of 200 mJ/cm2.
Effect of Polysilicon Deposition and Thermal Cycling on Thin Oxide Quality
Authors: Wu N.R. , Chiao S. , Bhushan B. , Batra T. , Fan S.K. , Pizzo P. , Yang C.Y. 
Published: March 2011

AbstractA scaled-down MOS transistor requires high-quality thin gate oxide (∼100 Å) as in tunnel oxide for an EEPROM device. Instead of investigating the lower (SiO2/Si) interface properties, we study the upper (poly-Si/SiO2) interface as affected by poly deposition conditions, phosphorus doping, and thermal cycling. The results show that prolonged or high-temperature heat treatment will degrade thin oxide quality. The initial V-t slope derived from constant-current stressing data is used to assess oxide quality.
Model of Porous Silicon Oxidation
Authors: Ore F. R. , Harwood P. B. 
Published: March 2011

AbstractA two-dimensional model for simulating the growth of SiO2in a porous Si layer is described. The model makes use of rapid early oxidation based on the presence of micropores in the oxide normal to the growing oxide-oxidant inter- face. With initial pore shape, ambient pressure and oxidation temperature as inputs, the model predicts the final morphology of the grown oxide film and calculates the refractive index and other key indicators of oxide quality. The model is a first step towards allowing the design of optimized processes for formation of high-integrity oxidized porous Si layers.
Dlts Ciiaracterizati oh of Precipitation Induced Microdefects
Authors: Whitwer F.D. , Haddad H. , Forbes L. 
Published: March 2011

AbstractCapacitance DLTS measurements have been performed on heavily precipitated n— and p—type silicon wafers. The results indicate heavy metal gettering with a mid-bandgap deep level (0.55eV) for n—type silicon. The results for p—type siliconshow a band of states present in the lower half of the bandgap. This band of states correlates well to the band of allowed energies found in heavily dislocated p—type silicon.
Fast Zerbst Transient Analysis and Application to Intrinsic Gettered P—type Epitaxial Wafers
Authors: Aminzader M. , Forbes L. 
Published: March 2011

AbstractOne of the principal difficulties in applying the Zerbst analysis to MOS capacitor transient recovery is the extremely long retention time of the MOS capacitor in high lifetimematerials. Typically the retention time is thousands of seconds at room temperature, so long times are required for a significant number of measurements. Furthermore, extrapolating the result of high temperature measurements back to room temperature can lead to large errors. A modified C—t transient response using a step from accumulation to depletion followed by light and then a small step from inversion to stronger inversion speeds up the generation lifetime measurement and separates the surface generation from the bulk generation. Pre— and post—epitaxial intrinsically gettered p/p+ wafers were subjected to high temperature CMOS process simulation and MOScapacitors with Al dots and guard rings were fabricated. Generation lifetime of about 5 msec were measured using the modified fast Zerbst method on properly intrinsically gettered epitaxial wafers, particularly the pre—epitaxial intrinsically gettered wafers.
Spinel Formation from Magnesium Aluminium Double Alkoxides
Authors: Jones Kenneth , Davies Thomas J. , Emblem Harold G. , Parkes Peter 
Published: March 2011

ABSTRACTDouble alkoxides of the general formula Mg[Al(OR)4]2 where R is iso-Pr or sec-Bu were prepared by reacting aluminium and magnesium metals together with the alcohol ROH and purified by vacuum distillation. They were characterised by IR, proton and 27Al NMR spectroscopy and MW determination. A magnesium aluminium double alkoxide was also prepared by treating the commercially available aluminium alkoxide ‘Aliso B’ [a mixed aluminium (iso-propoxide)(sec-butoxide)] with magnesium and iso-propanol. Treatment of magnesium aluminium double alkoxides with water and an alkanolamine (preferably triethanolamine) gives a rigid coherent gel. Viscosity measurements and 27Al NMR spectroscopy suggest that the double alkoxide does not break down to its constituents during hydrolysis. The air-dried gel was shown by XRD to convert quantitatively to spinel on firing to 1500°C. The resistance of the double alkoxide moiety to hydrolysis explains the ease of conversion to spinel on firing. The gel has been used to bind alumina and magnesia grain. Gels suitable for binding refractory grain were obtained only when the alkanolamine content corresponded to one alkanolamine group per metal atom. Electron micrographic and XRD studies showed that in fired refractory pieces, the bonding phase was spinel.
Synthesis of Oxide Ceramic Powders by Aqueous Coprecipitation
Authors: Moyer J. R. , Prunier A. R. , Hughes N. N. , Winterton R. C. 
Published: March 2011

ABSTRACTAqueous precipitation in a computer-controlled continuous crystallizer has been applied to the preparation of cordierite, mullite, alumina, and zirconia precursor powders. The particles are dense, spherical, and x-ray amorphous. The powders have a particle size range of 0.2–5 μm and a surface area of 1 – 10 m2/g The properties of the powders and of some green and fired pieces are described.
Prolonged Chaotic Oscillations During the Gel/Xerogel Transition in Silicon Tetramethoxide Polymerization as Detected by Pyrene Excimerization.
Authors: Kaufman Vered R. , Avnir David 
Published: March 2011

ABSTRACTWhen the polymerization of Si(OCH3)4is carried out in the presence of surface active agents, prolonged oscillations (over 1000 hrs) at the gel/xerogel transition are observed. The oscillations are of large amplitude, they are slow (several hrs/period), and they exhibit a chaotic behaviour. The probe by which these oscillations are observed is emission from excited state monomeric and excimeric pyrene. It is suggested tentatively that the driving forces for this oscillation are the structural relaxation of the secondary polymeric gel structure and the dispersion of adsorbed pyrene to thermodynamically favored adsorption sites. Relevant models could be those of oscillatory sol/gel phase transitions and of oscillatory polymerization reactions. We are unaware of previous observations of oscillations in sol/gel systems.
Silicon −29 Solids NMR-MAS Characterization of Non-Oxide Powders and Fibers
Authors: Inkrott Kenneth E. , Wharry Stephen M. , O'Donnell Dan J. 
Published: March 2011

ABSTRACTPowder x-ray diffraction has been the most common method for rapid structural analysis and identification of crystalline ceramic raw materials. However, new structural ceramic raw materials often have linebroadened or featureless XRD patterns due to structural strain or small crystallite size. Characterization of various silicon carbide and silicon nitride powders and ceramic fibers by Si-29 NMR-MAS spectroscopy has revealed structural details and differences in these materials previously indistinguishable by XRD or other routine methods. Unique variables intrinsic to a given ceramic synthesis process are reflected in the NMR-MAS spectra of the resulting products.
Synthesis of High Purity Silica Glass from Metal Alkoxide
Authors: Su S. R. , Onorato P. I. K. 
Published: March 2011

ABSTRACTHigh purity silica was synthesized by hydrolytic decomposition of tetramethylorthosilicate (TMOS), followed by polycondensation, supercritical drying and sintering. The key factors which govern the hydrolysis and polycondensation were systematically studied. Gas chromatography/mass spectrometry was used to monitor the hydrolysis rate. The hydrolysis of TMOS is the only reaction at ambient temperature in an acidic environment. The rate of polycondensation was also controlled by temperature as well as pH. The structural transformation from alkoxide to gel network and to glass was illustrated by FTIR. The structure of the TMOS derived supercritically dried gel sintered at 1000°C is identical to that of silica. The shrinkage kinetics and microstructural development of the gel heated at different temperatures was examined by dilatometry, B.E.T., TGA, and STEM. This combination of techniques showed that structural relaxation is not an important factor in the densification of these gels. Below 1000°C most shrinkage is due to condensation and water evolution. Above 1000°C, viscous sintering is the primary mechanism for shrinkage.
A Molecular Building-Block Approach to the Synthesis of Ceramic Materials
Authors: Klemperer W. G. , Mainz V. V. , Millar D. M. 
Published: March 2011

ABSTRACTCeramic materials are generally prepared from structurally simple starting materials, with the consequence that structural properties are difficult to control on a molecular level. This difficulty might be addressed by following the approach taken in polymer chemistry in which molecular building blocks are first prepared and then polymerized in a subsequent step. In the present case, the polysilicic acid esters [Si2O](OCH3)6, [Si3O2](OCH3)8, and [Si8O12](OCH3)8 are prepared and then polymerized by hydrolysis/condensation. Silicon-29 solution nuclear magnetic resonance (NMR) spectroscopy is used to estimate the extent to which the molecular frameworks of these monomers are retained during the course of hydrolysis and condensation.
Pyrolysis of Organosilicon Gels to Silicon Carbide
Authors: Fox Joseph R. , White Douglas A. , Oleff Susan M. , Boyer Robert D. , Budinger Phyllis A. 
Published: March 2011

AbstractSol-gel precursors to silicon carbide have been prepared using trifunctional chloro and alkoxysilanes which contain both the silicon and carbon necessary for SiC formation. Crosslinked gels having the ideal formula [RSiO1 5].]n have been synthesized by a hydrolysis/condensation scheme for a series of saturated and unsaturated R groups. The starting gels have been characterized by a variety of elemental analysis, spectroscopic and physical measurements including IR. XRD. TGA.. surface area and pore volume. A particularly powerful method for characterizing these gels is the combination of 13C and 29 Si solid state NMR which can provide information about the degree of crosslinking as well as residual hydroxy/alkoxy content.The controlled pyrolysis of these gels has been used to prepare silicon carbide-containing ceramic products with surface areas in excess of 600m2/gm. The pyrolysis products are best described as a partially crystalline, partially amorphous mixture of β-SiC, silica and carbon. The effect of carbon chain length and the degree of unsaturation in the R group on the composition and surface area of the product has been determined. The origin of the high surface area of the pyrolysis products has been identified and its implications on potential uses of these materials is discussed.
Thermal Conversion of Preceramic Polysilazanes to Si3N4: Characterization of Pyrolysis Prooucts
Authors: Schwartz Kenneth B. , Rowcliffe David J. , Blum Yigal D. , Laine Richard M. 
Published: March 2011

ABSTRACTCharacterization of the pyrolysis products of preceramic polysilazanes synthesized by reactions of the oligomer-[H2SiNMe]x in the presence of Ru3(CO)12catalyst has demonstrated that these polymers have great potential as precursors of Si3N4for several applications. The polysilazanes studied are viscous liquids that can be converted to ceramic material with a yield of >65 wt %. The vitreous product contains regions of fully dense material and large cavities that indicate of considerable gas evolution. A preliminary pyrolysis sequence has been constructed based on a combination of TGA of the polymer, SEM investigation of the product, and mass spectroscopic analysis of the gases and heavy fragments released during conversion of the polysilazanes to ceramic material. This understanding of pyrolysis mechanisms will aid in developing even more effective polymeric precursors to Si3N4and in optimizing pyrolysis procedures for a variety of useful appl ications.
Differences Between Gel-Derived Melts and Those Produced by Batch Melting
Authors: Cooper Alfred R. 
Published: March 2011

ABSTRACTProperties of a system at equilibrium depend on pressure, temperature and composition. Thus for a melt produced by the sol-gel (SG) process to be different from an identical composition melted from batch (MB), both cannot be at equilibrium. Non equilibrium melts can be associated with structural differences or homogeneity differences. The former have been suggested for SG melts while the latter is always possible in MB melts. Appropriate relaxation times are presented for structural and heterogeneity relaxation. From this it is concluded that structural differences will not persist unless the SG melt is metastable with respect to the equilibrium melt. A method for testing this unlikely premise is proposed.Melts which are imperceptibly different from equilibrium may have non-equilibrium crystal embryo distributions that relax toward equilibrium with a time constant longer than that for structural relaxation. A difference in embryo and stable nuclei distribution will result in different crystallization kinetics.