bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal and Photolytic Decomposition of Adsorbed Cadmium and Tellurium Alkyls
Authors: Stinespring C.D. , Freedman A. 
Published: March 2011

ABSTRACTStudies of the thermal and photon-induced surface chemistry of dimethyl cadmium (DMCd) and dimethyl tellurium (DMTe) under ultrahigh vacuum conditions have been performed for substrate temperatures in the range of 133 K to 295 K. Results on GaAs(100) and Si(100) surfaces indicate that for DMTe, the predominant adspecies, dimethyl tellurium, can be photodissociated to a metal adspecies at both 193 and 248 nm. For DHCd, the major adspecies, monomethyl cadmium, is unreactive to photon stimulation.
Epitaxial Silicon Layers Made by Reduced Pressure/Temperature CVD
Authors: Regolini J.L. , Bensahel D. , Mercier J. , D'Anterroches C. , Perio A. 
Published: March 2011

ABSTRACTIn a rapid thermal processing system working at a total pressure of a few Torr, we have obtained selective epitaxial growth of silicon at temperatures as low as 650°C. When using SiH2Cl2 (DCS) as the reactive gas, no addition of HCl is needed. Nevertheless, using SiH4 below 950°C a small amount of HCl should be added.Some kinetic aspects of the two systems, DCS/HCI/H2 and SiH4/HCl/H2, are presented and discussed. For the DCS system, we show that the rate-limiting reactions are slightly different from those commonly accepted in the literature, where the results are from systems working at atmospheric pressure or in the 20-100 Torr range.Our model is based on the main decomposition of DCS, SiH2Cl→SiHCl + HCl, instead of the widely accepted reaction SiH2Cl2→SiCl2 + H2. This is the main reason why no extra HCl is required in the DCS/H2 system to obtain full selectivity from above 1000°C down to 650°C.
X-Ray Lithography Studies of Polysilane using a Laser Plasma X-Ray Source
Authors: Kubiak Glenn D. , Outka Duane A. , Zeigler John M. 
Published: March 2011

ABSTRACTA laser-generated plasma source of monochromatized soft x-rays has been used to study the x-ray lithographic resist properties of poly(cyclohexylmethylsilane-co-dimethylsilane). X-ray absorption spectra near the SiL2,3 edge of unexposed samples were measured to guide the choice of exposure photon energy. We find that poly(cyclohexyl-methylsilane-co-dimethylsilane) exhibits positive tone at x-ray energies near 105 eV (Si 2p resonance), a sensitivity of 1000 mJ/cm2 and a contrast of 1.5. Sensitivity is found to increase markedly when exposed samples are held in air before development. Using simple wire mesh masks, estimates of the minimum achievable linewidth have been made.
Arf Laser-Induced Chemical-Vapor Deposition of Tungsten for Gate Electrodes
Authors: Matsuhashi H. , Nishikawa S. , Ohno S. 
Published: March 2011

ABSTRACTThe deposition of W films by ArF laser-induced chemical-vapor deposition (LCVD) was investigated as a function of incident laser power, WF6 and H2 partial pressures, and substrate temperature. The deposition of W films by LCVD is discussed dividing that into two parts, thermal CVD (TCVD) and photon assisted CVD (PhCVD). The rate of PhCVD has been defined as the difference between the rates with and without laser irradiation. The reaction orders for PhCVD are 1, 0 with respect to WF6 and H2 partial pressures, respectively, and the rate linearly increases with increase in laser repetition rate. The activation energy in PhCVD is 0.17 eV. These facts indicate that, in LCVD, PhCVD takes place independently of TCVD and that the deposition rate in PhCVD is determined by the formation of F radicals in the dissociation of WF6 molecules by laser irradiation.MOS capacitors with LCVD-W gates were fabricated and their characteristics were compared with those with sputtered-W gates. It was shown that the level of contamination due to mobile ions in the capacitor with the LCVD-W gate was extremely low.
A Study of Defects in Ordered Ternary Semiconductor Epilayers
Authors: McKernan S. , Carter C. B. , Bour D. P. , Shealy J. R. 
Published: March 2011

AbstractOrdered GaxIn1-xP epilayers grown on GaAs substrates have been studied in the electron microscope. Dark-field images and high-resolution micrographs have directly revealed the presence of an ordering of the Ga and In (111) planes. Several different planar defects have been identified in the ordered structure. There is a very high density of faults parallel to the (001) growth surface. Models for these faults have been constructed in terms of stacking faults and twin boundaries in the ordered structure. Other flat planar defects which occur approximately parallel to (111) and (111) planes can also be described in these terms.
Gold-Nickel Multilayer Films: Structure-Property Correlations
Authors: Nutt S. R. , Green K A. , Baker S. P. , Nix W. D. , Jankowski A. 
Published: March 2011

AbstractGold-nickel multilayer films with periods of 1.2 - 4.6 nm were deposited on silicon substrates by magnetron sputtering, and plan and cross-sectional specimens were examined by transmission electron microscopy. The cross-sectional specimens revealed well-defined layering and columnar growth features that extended through the film thickness. Dark striations extending normal to the layers were attributed to diffraction contrast from defect strain fields. Diffraction patterns showed that the films were highly textured and that short-period films had a single fcc structure, while long-period films separated into three fcc structures. High-resolution images of the layer interfaces showed local regions of epitaxy partitioned by regions of disorder.Indentation tests using a Nanoindenter, a depth-sensing indentation device, were performed to measure the elastic modulus and hardness of the films. No modulus enhancement was detected, and a small variation in hardness was measured.
Stress Gradients and Anisotropy in Thin Films
Authors: Fisher Robert M. , Duan J. Z. , Fox Alan G. 
Published: March 2011

AbstractIndications that steep through-thickness strain gradients occur in vapour-deposited chromium films stemming from previous observations of film curling during spontaneous delamination from substrates, have been substantiated by analysis and simulation of Bragg X-Ray diffraction peaks. The presence of large through-thickness compressive strains, that increase quadratically with distance from the substrate from about zero at the interface to around 0.8% at the film surface, was deduced by empirical computer matching of diffraction peak shapes.
Residual Stress Analysis of Al Alloy Thin Films by X-Ray Diffraction as a Function of Film Thickness
Authors: Shute Carla J. , Cohen J. B. , Jeannottea D. A. 
Published: March 2011

AbstractResidual stress has been measured as a function of layer thickness in thin films of an Al alloy on oxidized Si by the x-ray “d” versus sin2ψ technique. Samples with and without a passivation layer were examined. The results show an increase in residual stress with decreasing film thickness for the passivated samples and indicates that the interface between the metal film and SiO2 may be a region of high stress.
Thin HgCdTe LPE Layers Grown on CdTe and CdZnTe Substrates
Authors: Yamamoto Kosaku , Maekawa Tohru , Takigawa Hiroshi 
Published: March 2011

AbstractThe dependence of the growth pattern of thin HgCdTe LPE layers on lattice mismatch was investigated. Epilayers grown on substrates with a lattice mismatch of more than 0.2% show island-like growth, which are aligned with the network of misfit dislocation lines. Thin epilayers grown on substrates with a lattice mismatch of less than 0.05% have mirror-like flat surfaces. It was found that the surface defects for thick epilayers also have a lattice-mismatch dependency.
Viscoelastic Stress Relief in Patterned Silicon-on-Insulator Structures
Authors: Letavic Theodore J. , Maby Edward W. , Gutmann Ronald J. 
Published: March 2011

AbstractA high-temperature viscoelastic stress relief technique has been investigated as a means for reducing in-plane stress encountered during zone-melt recrystallization of patterned silicon-on-insulator structures. This technique incorporates a phosphosilicate glass layer between the silicon film and the insulating substrate to provide a viscous flow mechanism for stress relief within the composite structure. The stress relaxation can bequalitatively described by a mechanical model which couples thermal expansion and viscoelastic flow. The model predicts the time constant for stress relief at high temperatures as a function of pattern size, and the results are useful as a design aid for zone-melt recrystallization experiments.
The Relationship between Intrinsic Stress of Silicon Nitride Films and Ion Generation in A 50 KHz RF Discharge
Authors: Aite K. , Holleman J. , Middelhoek J. , Koekoek R. 
Published: March 2011

AbstractSilicon nitride films prepared by the Plasma Enhanced Chemical Vapor Deposition technique (PECVD) are widely used in microelectronics. The intrinsic stress value of the silicon nitride films is a key factor which determines their reliability. A low frequency (50 kHz) RF discharge and a N2/NH3 /SiH4 gas mixture were used to deposit silicon nitride films on 4-inch silicon wafers in a horizontal hot-wall reactor at a temperature of 350 °C.The compressive stresses in the deposited films were found to increase linearly with the nitrogen ionization created in the glow discharge. The nitrogen ion bombardment at the film surface induces ion implantation into the deposited film which results in film expansion. The stresses were deduced by the interference fringes technique and from surface profiler measurements. Optical Emission Spectroscopy of the N2/NH3/SiH4 discharge was used for measuring the N+2 peak intensity variation with the partial pressure of the nitrogen gas.When the nitrogen ionization was increased, a shift of the main infrared transmission peak corresponding to the Si-N bond in the silicon nitride films was observed using Fourier Transform Infrared Spectroscopy (FTIR). The Si-H and N-H infrared peaks in the films were not affected by the ion bombardment. A linear relationship was found between the wavenumber of the main infrared Si-N peak νM (835–875 cm−1) and the intrinsic stress σi of the deposited nitride films with the slope dνM/dσi −4.85×10−8 cm−1 /Pa.
Thermal Strain Measurements in Epitaxial CoSi2/Si by Double Crystal X-Ray Diffraction
Authors: Bai Gang , Nicolet Marc-A. , Vreeland Thad , Ye Q. , Kao Y. C. , Wang K. L. 
Published: March 2011

AbstractThe perpendicular x-ray strain of epitaxial CoSi2 films grown on Si(111) substrates at ∼ 600°C by MBE was measured at various temperatures. Within experimental error margins, the strain decreases linearly with rising temperature at a rate of (1.3±0.1) × 10-5/°C from room temperature up to 600°C. Over that temperature range and the duration of a complete measurement (∼5h to ∼ 2h), these strain values remain reversible. At 593°C, the x-ray strain is -0.85%, which is about the strain that a stress-free CoSi2 film on Si(111) would have at that temperature. This results show that the stress in the epitaxial CoSi2 film is fully relaxed at the growth temperature. Strains below the growth temperature are induced in the film by the difference in the linear coefficient of thermal expansion of CoSi2 and Si. They were calculated by assuming that the density of misfit dislocations formed at the growth temperature remains constant. The slope of the strain-temperature dependence obtained that way agrees with the measured slope if the unknown Possion ratio of CoSi2 is assumed to be VcoSi2 = 0.35. A film stress of ∼ 0.8 GPa at room temperature was calculated using the above value for the Possion ratio, 130 GPa for the Young modulus, and the measured x-ray strain.
Stresses in Films Deposited by Planar Magnetron Sputtering on Glass Substrates of Different Thickness
Authors: Zhou Zhi-Feng , Fan Yu-Dian 
Published: March 2011

AbstractStresses affect the structure and properties of the films significantly. In this paper, Co-Cr films were deposited by D.C. planar magnetron sputtering on rectangular glass plates of thickness varied from 0.18 to 2.00mam. The measurement of stress was performed by the bending plate technique with the detection of capacitance change. The temperature of the bending plate was measured by an Fe-Ni thin film thermocouple on the back side of the substrate. The experimental results showed that the stresses were all tensile, but in the films on the thicker substrates were smaller than that on the thinner ones. And apparently the temperature rise of the thicker substrates during deposition was lower than that of the thinner ones. The magnetic characteristics of the Co-Cr films related to the substrate thickness may be attributed to both stress and temperature difference in the films deposited on the substrates of different thickness.
Mechanical Stress as a Function of Temperature in Thin Aluminum Films and its Alloys
Authors: Gardner Donald S. , Flinn Paul A. 
Published: March 2011

AbstractAluminum alloys have virtually replaced aluminum for interconnections in VLSI because of their improved reliability. Mechanical stress is a problem of growing importance in these interconnections. Stress as a function of temperature was measured for thin aluminum films and several aluminum alloys and layered films consisting of silicon, copper, titanium, tungsten, tantalum, vanadium, and TiSi2. Solid-state reactions of the aluminum with the additives and with the ambient during thermal cycling will occur and depending on what compounds have formed and at what temperature, this will determine the morphology and reliability of the metallization. The measurement technique, based on determination of wafer curvature with a laser scanning device, directly measures the total film stress and reflectivity in situ during thermal cycling. Changes in stress were detected when film composition and structure varied and were correlated using x-ray diffraction with the formation of aluminides. Other phenomena that contribute to stress changes including elastic behavior, recrystallization, grain growth, plastic behavior, yield strength, and film hardening from precipitates.
Adsorption of Silicon Tetrachloride on Si(111) 7×7
Authors: Gupta P. , Coon P. A. , Koehler B. G. , George S. M. 
Published: March 2011

ABSTRACTThe kinetics of SiCl4 adsorption on Si(lll) 7×7 were studied using laser induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. The initial reactive sticking coefficient of SiCl4 on Si(lll) 7×7 was observed to decrease with increasing surface temperature. This decrease was consistent with a precursor-mediated adsorption model. Both LITD and TPD experiments monitored SiCl2 as the main desorption product. These results suggest that SiC12 may be the stable chlorine species on the Si(lll) 7×7 surface.
Silicon Suboxides: The “Co-Deposition” of a-Si:H and SiO2
Authors: Tsu D. V. , Lucovsky G. , Watkins M. W. 
Published: March 2011

ABSTRACTThe deposition mechanism of silicon suboxides (SiOx, x<2) prepared by remote plasma enhanced chemical vapor deposition (Remote PECVD) is investigated. These films were deposited in a Deposition/Analysis chamber designed to investigate the gas phase chemistry. In this technique, an O2/He mixture is plasma excited, and the silane reactant is injected into the deposition chamber down-stream from the plasma tube. We show that if the plasma after-glow is prevented from extending into the deposition region by an electrical grid placed between the plasma tube and the deposition region, silicon dioxide is then deposited for all O2/He mixtures investigated (0.1 to 1.0 %). In contrast, hydrogenated suboxides of silicon are deposited when the plasma after-glow is allowed to extend past the grid into the deposition region.
Surface Chemistry on Microclusters: Recent Results from Silicon and Germanium Cluster Beams
Authors: Alford J. M. , Smalley R. E. 
Published: March 2011

ABSTRACTSupersonic cluster beam techniques have recently produced some fascinating new information as to the surface chemistry and physics of small (2–100 atom) clusters of various semiconductors. For example, it appears that silicon clusters exhibit a remarkably pronounced alternation in reactivity as a function of cluster size. For ammonia chemisorption certain clusters such as Si33+, Si39+, and Si45+ have been found to be almost completely inert, while neighboring clusters such as Si36 and Si45+ chemisorb ammonia readily. Such sharply patterned reactivity results may provide significant clues as to the detailed nature of semiconductor surface restructuring and the consequent effects of this restructuring upon the surface chemistry.
Contributions of Gas Phase Reactions to CVD Processes
Authors: Desu S. B. , Kalidindi Surya R. 
Published: March 2011

ABSTRACTAn analytical model to account for the effects of gas phase reactions in CVD processes is presented. In this model a system with only two reactions, gas phase production of an intermediate and reaction of the intermediate on the surface of the substrate to form the film is considered. The reaction kinetics, convective and diffusive transport mechanisms are coupled to analyse the thickness distribution over the length of the reactor.Theoretical deposition rate profiles in the direction of gas flow are shown with varying deposition temperatures and gas flow velocities for both surface and gas phase reaction controlled mechanisms. It has been shown that by analyzing the nature of the deposition rate profiles, the rate limiting step in a CVD process can be identified.
Electronic Structure of Adsorbed Trimethylaluminum on Clean Si(100) Surfaces
Authors: Motooka T. , Fons P. , Greene J. E. 
Published: March 2011

ABSTRACTThe electronic structure of dimerized trimethylaluminum (TMA), Al2(CH3)6. adsorbed on Si(100) surfaces has been investigated using molecular orbital (MO) calculations based on a cluster description of TMA/Si(100). The calculated results suggest that the interactions between TMA and the Si(100) surface are described by overlap of the TMA electron-deficient bond and Si surface dangling-bond orbitals. The electron-deficient bond orbital is the highest occupied MO of TMA and acts as an electron acceptor for charge transfer from a surface Si atom to TMA consistent with observed core-level and valence photoelectron spectra.
Purposeful Chemical Design of Mocvd Precursors for Silicon-Based Systems
Authors: Aylett Bernard J. 
Published: March 2011

ABSTRACTIt is shown that volatile molecular compounds with silicon-metal bonds can act as effective MOCVD precursors to metal silicides, which aredeposited as thin films under relatively mild conditions. Strategies for the design and synthesis of such “prevenient” precursors are explored, and possible extensions of this approach are considered.
Chemical Vapor Deposition of Silicon Carbide Using a Novel Organometallic Precursor
Authors: Lee Wei , Interrante Leonard V. , Czekaj Corrina , Hudson John , Lenz Klaus , Sun Bing-Xi 
Published: March 2011

ABSTRACTDense silicon carbide films have been prepared by low pressure chemical vapor deposition (LPCVD) using a volatile, heterocyclic, carbosilane precursor, MeHSiCH2SiCH2Me(CH2SiMeH2). At deposition temperatures between 700 and 800° C, polycrystalline, stoichiometric SiC films have been deposited on single crystal silicon and fused silica substrates. Optical microscopy and SEM analyses indicated formation of a transparent yellow film with a uniform, featureless surface and good adherence to the Si(lll) substrate. The results of preliminary studies of the nature of the gaseous by-products of the CVD processes and ultrahigh vacuum physisorption and decomposition of the precursor on Si(100) substrates are discussed.
Chemical Vapor Deposition of Chromium Carbide from Organometallic Precursors
Authors: Rutherford N. M. , Larson C. E. , Jackson R. L. 
Published: March 2011

ABSTRACTChemical vapor deposition from CpCr(CO)3H, Cr(CH2CMe3)4, and Cr(NPri2)3at low pressures yields chromium carbide films at temperatures as low as 330 °C. The films are mirror-bright and extremely smooth with no significant features observable by SEM. In general, films prepared at higher temperatures had lower resistivities, and were more likely to be crystalline than those prepared at lower temperatures. However, amorphous films deposited at 330 °C were much harder than the crystalline films. Chemical vapor deposition from Cr(NPri2)3resulted in carbide films with the most desirable properties.
Surface Processes in CVD: Laser- and Low Energy Electron-Induced Decomposition of W(CO)6 on Si(111)-(7×7)
Authors: Friend Cynthia M. , Swanson J. R. , Flitsch F. A. 
Published: March 2011

ABSTRACTThe decomposition of W(CO)6 adsorbed on Si(111)-(7×7) using low energy electrons and ultraviolet photons has been investigated under ultrahigh vacuum conditions. This work is motivated by a desire to understand the mechanism for laser- and electron-assisted chemical vapor deposition (CVD) of tungsten using volatile coordination complexes and to specifically understand the role of the surface in these processes. Both electron stimulated and photo-assisted decomposition of the adsorbed W(CO)6 are observed. No thermal decomposition of the W(CO)6 occurs under the conditions of these experiments, based on independent temperature programmed reaction experiments, ruling out the possibility of laser- or electron-induced heating as the cause of decomposition. Furthermore, the interaction of the W(CO)6 with the Si(111)-(7×7) surface is shown to be exceedingly weak based on the fact that the desorption energy is 9.46 ± 0.77 kcal/mol. Desorption of CO is induced during both ultraviolet photolysis and electron bombardment. Carbon monoxide is exclusively evolved during ultraviolet photolysis: no W-containing fragments are desorbed. During electron bombardment, a small amount of the W(CO)6 is desorbed, accounting for ∼10% of the desorption. In both cases, CO-containing W fragments remain on the surface after decomposition at low surface temperature. The remaining surface fragments do not undergo further photolysis at 308 nm but do react thermally. Competing desorption and dissociation of CO are thermally induced resulting in carbide and oxide impurities in the deposited material. The fact that strongly bound W(CO)x fragments are trapped on the surface is proposed as a limiting factor in the purity of tungsten deposits using the decomposition of W(CO)6.
Excimer Laser Photodissociation Studies of Disilane AT 193 nm
Authors: Jasinski J. M. , Chu J. O. , Begemann M. H. 
Published: March 2011

ABSTRACTOptical emission, laser spectroscopic and mass spectrometric techniques have been used to study the ArF excimer laser induced photochemistry of disilane at 193 nm. Evidence is found for the formation of a number of photofragments from single and multiphoton dissociation. Effects due to secondary photolysis are observed at high excimer laser repetition rates.
Uv Excimer Laser Induced Prenucleation of Surfaces from Spin-on Films Followed by Electroless Metallization
Authors: Esrom Hilmar , Wahl Georg , Stuke Michael 
Published: March 2011

ABSTRACTUV excimer laser light-induced prenucleation of various surfaces from spin-on films in air is described. Good results were obtained using palladium acetate on substrate materials ranging from ceramics to polymers and even paper. Virtually any surface material can be prenucleated in this way. The Pd-prenucleated planar and curved surfaces can be metallized by a vast variety of metals using electroless plating solutions (Cu, Ni, Au, Pt, Co, Sn, and even alloys). Results are described in detail for copper from a standard electroless solution (Doduco or Shipley). Contact metallization through via holes using this process was aachieved with excellent contact properties.