bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silicide Formation By High Dose Transition Metal Implants Into Si.
Authors: Sanchez F. H. , Namavar F. , Budnick J. I. , Fasihudin A. , Hayden H. C. 
Published: March 2011

ABSTRACTWe report preliminary results of a study on silicide formation by means of high dose transition metal implants into Si (100) single crystals.100 keV Cr+, Fe+, Co+ and Ni+ were implanted at room temperature. For the Cr+, Fe+ and Ni+ implants, no silicide formation was observed after implantation. However, both Rutherford Backscattering Spectrometry (RBS) and X-Ray Diffraction (XRD) results clearly indicated the existence of CrSi2 after the Cr-Si samples were annealed 4 hours at 550°C. In the case of the Fe+ and Ni+ implants, FeSi2 and NiSi2 were identified by XRD after annealing the implanted samples half an hour at 400°C. A layer of CoSi of about 1000 Å was observed in the as implanted Co-Si samples by both RBS and XRD.Ni+ ions accelerated to 150 keV were implanted at 350°C. A much broader distribution and higher retention of Ni was obtained in this case, showing evidence of long range atomic diffusion. NiSi and polycrystalline silicon were observed by XRD in the as implanted samples.The possibility of high dose ion implantation as a suitable technique for producing transition metal silicides is discussed.
Amorphisation, Crystallisation And Related Phenomena In Silicon
Authors: Williams J.S. 
Published: March 2011

ABSTRACTThis review examines recently observed phenomena associated with amorphisation and crystallisation of silicon under ion bombardment and furnace annealing. Ideally, heavy ion damage should completely amorphise the silicon surface layers so that the underlying crystal can provide a perfect template for subsequent epitaxial growth. However, in practise the ion bombardment and annealing behaviour can be decidedly more complex. During ion bombardment of silicon, several correlated processes can take place depending on the target temperature and the precise bombardment conditions. These processes include: defect production; amorphisation; diffusion and segregation of defects and impurities; and ion-beam-induced (epitaxial) crystallisation. During subsequent heat treatment, amorphous layers can exhibit anomalous impurity diffusion and precipitation effects, nucleation of random crystallites, and solid phase epitaxial growth. In addition, the kinetics of the epitaxial growth process are sensitive to the type and state of implanted impurities present in the silicon. The competition between random nucleation and epitaxy is also dominated by impurity effects. Finally, correlations between all of these phenomena provide i) considerable insight into impurity and defect behaviour in amorphous and crystalline silicon, and ii) a better understanding of the amorphous to crystalline phase transition, including mechanisms of solid phase epitaxial growth.
Laser Recrystallization of InP Films on Oxidized Si Substrate
Authors: Xiqiang Li , Weiwen Zhu , Chenglu Lin , Weiyuan Wang , Shihchang Tsou 
Published: March 2011

ABSTRACTThe InP films with thickness of 1-2 µm and resistivity of 10-10−3Ω-cm were sputtered on oxidized Si substrates heated at about 300°C to form as InP SOI. Using X-ray diffraction, ED, TEM, Hall and RBS, we have investigated the grain size, compositions, thermal stability and electrical characteristics of InP SOI before and after CW Ar+ laser recrystallization. The sputtered InP SOI films appear as polycrystalline and its grain size increases with increasing of irradiated laser power from 5.8 to 7.0 W at a beam diameter of 70 µm. After irradiation at 7 W the single crystal ED patterns are obtained, the mobility and carrier concentrations amount to 103cm2/Vs and 1017cm−3, respectively, and the compositions are stoichiometric.
A Study of Melting and Resolidification of Silicon-on-Insulator Structures Formed by Lateral Epitaxy
Authors: Williams D A , Mcmahon R A , Hasko D G , Ahmed H , Hopper G F , Godfrey D J 
Published: March 2011

ABSTRACTThe formation of silicon-on-insulator structures, by recrystallising polycrystalline silicon films with a dual electron beam technique, has been studied over a wide range of conditions. The quality of the layers has been assessed by examining cross-sections in the SEM and optical microscopy of the surface after a Secco etch. The range of line powers which gives device-worthy single crystal material becomes greater as the sweep speed increases and as the background temperature is reduced. The extent of melting into the substrate in the seed windows and below the isolating oxide was determined from the movement of an arsenic implant. The experimental results are compared to the predictions from a one dimensional model for the heat flow.
Improved Soi Films By High Dose Oxygen Implantation and Lamp Annealing
Authors: Celler G. K. , Hemment P. L. F. , West K. W. , Gibson J. M. 
Published: March 2011

ABSTRACTIon beam synthesis of a buried SiO2 layer is an attractive silicon-on-insulator technology for high speed CMOS circuits and radiation hardened devices. We demonstrate here a new annealing procedure at 1405°C that produces silicon films of excellent quality, essentially free of oxygen precipitates and with sharp interfaces between the Si and the SiO2.
Heavy Metal Gettering in Implanted Buried-Oxide Structures
Authors: Kamins T. I. , Chiang S. Y. 
Published: March 2011

ABSTRACTTo investigate gettering of heavy metal impurities to the damaged regions surrounding an implanted buried oxide, the behavior of chrominum and copper on annealing has been investigated. Cr tends to segregate to the surface Si-SiO2 interface, although a small fraction moves to the damaged regions surrounding the buried oxide. Cu segregates to the damaged regions more readily; in addition, a large fraction of the implanted Cu moves to a location several micrometers beneath the buried oxide layer. The buried oxide does not appear to stop the movement of the Cu.
Strain and Damage in Silicon Due to a Deep Oxygen Implantation
Authors: Vreeland Thad , Jayadev T.S. 
Published: March 2011

ABSTRACTSilicon wafers, implanted with oxygen at 550°C to form a buried oxide layer have been examined with TEM and x-ray diffraction. Implantation damage increased with depth up to ~1500 Å where some amorphous regions were seen. The amorphous region extended for -4500 Å to a damaged crystalline region ~1000 Å thick. Double crystal x-ray rocking curves of the as-implanted and of annealed crystals were obtained and analyzed. The strain normal to the (100) surface in the as-implanted crystalline Si did not exceed +0.05%. After an argon anneal, the strain disappeared, leaving a crystal with a lower density of extended defects and no measureable misorientation of surface or deep layers. In marked contrast, an anneal in a hydrogen atmosphere exhibited no normal strain but contained regions above the oxide layer which differed in orientation from the substrate. The misorientation ranged up to ~0.1 degree.
The Physical and Electrical Properties of Buried Nitride Soi Structures Synthesized By Nitrogen Ion Implantation
Authors: Slawinski C. , Mao B.-Y. , Chang P.-H. , Lam H.W. , Keenan J.A. 
Published: March 2011

ABSTRACTBuried nitride silicon-on-insulator (SOI) structures have been fabricated using the technique of nitrogen ion implantation. The crystallinity of the top silicon film was found to be exceptionally good. The minimum channeling yield, Xmin' was better than 3%. This is comparable to the value observed for single crystal silicon. The buried insulator formed during the anneals has been identified as polycrystalline α-Si3 N4 with numerous silicon inclusions. This nitride, however, has been found to remain amorphous in regions at the center of the implant where the nitrogen concentration exceeds the stoichiometric level of Si3N4. Nitrogen donor formation in the top silicon layer has also been observed.
Interpretation of Uv Reflectance Measurements on Silicon-On-Sapphire By Spectral Reflectance and Spectroscopic Ellipsometry Studies
Authors: Pickering C. , Hodge A.M. , Daw A.C. , Robbins D.J. , Pearson P.J. , Greef R. 
Published: March 2011

ABSTRACTSpectral reflectance and spectroscopic ellipsometry measurements have been made on SOS wafers with haze ratings 1-5. The wavelength dependence of reflectance is dominated by surface scattering, but degraded crystallinity effects are also observed, and are significant in some samples. Analysis of dielectric function spectra using an effective medium approximation has indicated the presence of α-Si and voids in surface layers up to 300Å thick in medium haze wafers, with concentrations decreasing away from the surface. The assessment parameter normally used for SOS, UVR No., has been shown to includeboth crystallinity and scattering effects, and their relative importance cannot be determined without more detailed measurements.
Electrical Characterization of Crystallized—Silicon Thin Films
Authors: Johnson N. M. 
Published: March 2011

ABSTRACTA review is presented on the application of electrical measurements to evaluate the existence and effects of residual electronic defects in crystallized—silicon thin films. Experimental techniques include current—voltage characterization, electronbeam—induced conductivity, transient—capacitance measurements on thin—film capacitors, transient—conductance spectroscopy on thin—film transistors, and photoconductivity.
Assessment of Silicon—On—Insulator Technologies for Vlsi
Authors: Tsaur B-Y. 
Published: March 2011

ABSTRACTA high—performance, cost—effective silicon—on—insulator (SOI) technology would have important near—term applications in radiation—hardened electronics and longer term applications in submicrometer VLSI. The advantages of SOI over bulk Si technology for these applications will be outlined, and CMOS, CJFET, andbipolar device structures being developed for SOI will be discussed. The current status and future prospects of the two most promising SOI technologies —— beam recrystallization and high—dose oxygen implantation —— will be reviewed, with emphasis on such issues critical to commercialization as material quality and manufacturing feasibility.
Elimination of Subboundaries from Zone-Melting-Recrystallized Silicon-On-Insulator Films
Authors: Geis M. W. , Chen C. K. , Smith Henry I. , Nitishin P. M. , Tsaur B-Y. , Mountain R. W. 
Published: March 2011

ABSTRACTSince the introduction of zone-melting recrystallization (ZMR)for silicon-on-insulator (SOI) films, subboundaries (low-angle grain boundaries) have been the major crystalline defects in recrystallized films. By using an improved ZMR procedure, subboundaries have been eliminated over large areas. The improvements include the use of 1-µm-thick polycrystalline-Si films deposited on 2-µm-thick thermal SiO2 film (instead of 0.5-µm-thick Si and SiO2 films), a new encapsulation technique, and improved control of the thermal gradient during ZMR. Recrystallized SOI films without subboundaries contain isolated dislocations with densities <2 × 106 cm−2.
Low Temperature Polycrystalline Silicon Thin Film Devices for Large Area Electronics
Authors: Hawkins William G. 
Published: March 2011

ABSTRACTA process sequence for polycrystalline silicon NMOS logic circuitry is presented here. The fabrication sequence eliminates ion implantation steps and requires a maximum process temperature of 900°C. Low process temperature and diffusion doping may allow use of high temperature glass as substrates. Diffusion doping of large substrates eliminates expensive modification of an ion implanter. Initial Work utilized ion implantation to dope device channels before oxidation. Phosphorus channel doping is effective in the control of device threshold, based on the observation that both enhancement and depletion mode device behavior can be obtained. Boron doping is not effective because segregation of the boron into SiO2 occurs during subsequent oxidation. The results obtained from ion implantation doping show that functioning NMOS gates can be fabricated. In fact, it was discovered that undoped polycrystalline silicon channels provide suitable enhancement mode devices, while lightly phosphorus doped channels yield depletion mode devices. A process sequence based solely on phosphorus diffusion is then demonstrated.
Capping Techniques for Zone-Melting-Recrystallized Si-On-Insulator Films
Authors: Chen C.K. , Pfeiffer L. , West K.W. , Gels M.W. , Darack S. , Achaibar G. 
Published: March 2011

ABSTRACTTo prepare silicon-on-insulator (SOI) films by graphite-strip-heater zone-melting recrystallization (ZMR), a capping technique must be used to insure wetting by the molten Si zone. We have demonstrated two new capping techniques that result in reproducible wetting without degrading the crystallographic texture of the recrystallized film: annealing SiO2- capped Si films in NH3 and depositing two SiNx layers with carefully controlled compositions on the SiO2 capping layer. Wetting is promoted by the incorporation of trace amounts of nitrogen at the Si-SiO2 interface. Both N implantation experiments and Auger spectroscopy studies establish that the presence of less than a monolayer of nitrogen at this interface is sufficient to insure wetting.
A Seeded Channel Approach to Silicon-On-Insulator Technology
Authors: Ting C. H. , Baerg W. , Lin H. Y. , Siu B. , Hwa T. , Sturm J. C. , Gibbons J. F. 
Published: March 2011

ABSTRACTA seeded channel approach was developed to avoid the short comings of the conventional SOI structure such as grain or sub-grain boundaries in the channel region, floating substrate effects, etc. In this approach, the gate of each FET is located above its own seed window to insure that single crystalline material is obtained for the channel region. The source and drain regions, however, are located in the recrystallized silicon over Si02 for improved isolation and minimizing junction capacitance. Recrystallization was obtained in 4" silicon wafers by using an Ar laser and a computer controlled X-Y stage with heated substrate holder. Problems encountered in laser recrystallization, such as, reflectivity variations over seed and SOI regions, surface ripples, pittings, etc., were eliminated by optimizing the thin film thickness of the isolation oxide, polysilicon, and the capping oxide. This technology was used successfully to fabricate FET devices using a standard production n-MOS process. Good device characteristics were obtainred using 400Å gate oxide and channel length ranging from 1um to 50um. The measured electron mobility in the channel region is, however still lower than the ideal bulk values.
Electronic Structure Of Silicide-Silicon Interfaces
Authors: Bisi O. 
Published: March 2011

ABSTRACTSignificant understanding of the processes occurring at the interface between transition metal ultrathin overlayers and silicon has been achieved in recent years. In general these interfaces are highly reactive and the formation of an interfacial suicide compound takes place. The reaction at the near-noble metal-silicon interface can occur even at liquid nitrogen temperature. Furthermore the reaction products can give rise to epitaxial interfaces. How can the covai ent bonds in silicon be broken at such a low temperature and eventually give rise to an epitaxial interface are intriguing questions, which cannot be answered without a full understanding of the electronic and atomic processes involved in the interface reaction.Theoretical investigation‘through band structure calculations allows us to understand the modifications of the suicide electronic states in the interface region. Assuming various interface geometries (e.g. epitaxial growth or interstitial interdiffusion) the effect of different atomic processes on the electronic properties is analysed and available photoemission and Auger spectroscopie experimental informations are interpreted. The role of both electronic states and atomic processes in determining the interface physical properties is discussed.
Early Stages Of Reaction Between Amorphous Ni-Nb And Crystalline Au Films
Authors: Dobisz E. A. , Craighead H. G. , Perepezko J. H. , Wiley J. D. , Doyle B. L. , Peercy P. S. 
Published: March 2011

ABSTRACTThin film interactions between a-(Ni-Nb) and polycrystalline Au over-layers have been studied with high depth resolution (≤1.7nm) Rutherford backscattering (RBS) and TEM to obtain information on the early stages of reaction at the interface. The RBS spectra from Au indicated that the interdiffused samples consisted of two layers: an Au-Nb binary layer on the surface and a ternary Au-Ni-Nb compound layer beneath the binary layer. The growth kinetics of the ternary compound layer differed in samples which had been relaxed prior to Au deposition from the kinetics for unrelaxed samples. Furthermore, cross section TEM micrographs showed that relaxed and unrelaxed samples exhibit different microstructures after the early stages, of annealing. We interpret this result to indicate that the reaction stages in relaxed samples are not as advanced as those in the unrelaxed samples.
Reaction Of Amorphous And Crystalline Alloys With Silicon
Authors: Hung L. S. , Wang S. Q. , Mayer J. W. , Saris F. W. 
Published: March 2011

ABSTRACTThe reaction of Ni- refractory metal alloys with silicon has been studied by backscattering spectrometry and transmission electron microscopy. The analysis of the as-deposited sample revealed solid solutions for Ni-Cr and amorphous phases for Ni-Ta and Ni-Ti. In situ annealing resulted in crystallization of Ni43 Ta57 at 750 °C, a value above the reaction temperature of the alloy with silicon. The amorphous alloy of Ni48Ti52 was transformed into the equilibrium compound of NiTi at 450 °C, much below the reaction temperature. Phase separation has been observed in the Ni-Cr and Ni-Ta systems with a Ni- silicide layer next to the Si substrate and a refractory disilicide layer on the other side. In contrast, Si reacts with the NiTi compound to form a uniform mixed layer with a composition of NiTiSi2. The different behavior is explained based on considerations of both thermodynamic and kinetic terms.
In Situ Ellipsometric Studies of Palladium Silicide Formation
Authors: Kelso S. M. , Nemanich R. J. , Doland C. M. 
Published: March 2011

ABSTRACTWe have studied the formation of palladium suicide on clean silicon <111> surfaces using in situ spectroscopie ellipsometry. Pd films of thicknesses from 5 to 50 A were studied both as deposited and after annealing to complete the reaction to Pd2Si. The measured dielectric function spectra were analyzed to determine the amounts of Pd2Si and unreacted Pd. Evidence of Pd-Si solid state reaction was detected after all depositions. In the as-deposited films the fraction of suicide increased with the thickness, up to about 40% for the thickest films (50 Å Pd), while the annealed films were completely reacted. These results are consistent with earlier Raman spectroscopy studies.
Epitaxial Growth of CaxSr1−xF2 Layers on CaF2 by Vacuum Evaporation
Authors: Norton Nicholas G. , Knight K. S. 
Published: March 2011

ABSTRACTThe evaporation and epitaxial growth on single crystal CaF2 substrates of CaF2/SrF2 mixtures are investigated. The evaporated films are studied with X-ray diffraction and optical microscopy.X-ray diffraction results show that the evaporation of yCaF2 + (1 - y)SrF2 mixtures from a single boat, with y in the range 0 to 1, result in single phase, mixed crystals of composition CaxSr1−xF2. If Vegard's law is assumed to apply it is found experimentally that the film composition is the same as that of the source.For the evaporation of CaF2 and SrF2 onto cleaved CaF2 crystals it is shown that the best quality epitaxial films are obtained at substrate temperatures of∼400°C. At temperatures <400°C there is some broadening of the X-ray diffraction spots from the overlayer compared with those from the substrate. At temperatures>400°C there is a tendency for the epitaxial films to delaminate from the substrate.
Reaction And Interdiffusion at III-V Compound Semiconductor-Metal Interfaces
Authors: Brillson L. J. 
Published: March 2011

ABSTRACTThe characterization of III-V compound semiconductor-metal interfaces by surface science techniques has led to new relationships between interfacial chemistry and Schottky barrier formation. These and recent results on ternary alloy III-V compounds suggest a greater control of Schottky barrier heights by atomic scale techniques and advanced III-V materials than previously believed.
Phase Formation Sequence In The Pd-Gaas System
Authors: Sands T. , Keramidas V. G. , Yu A. J. , Yu K. M. , Gronsky R. , Washburn J. 
Published: March 2011

ABSTRACTThe morphological aspects of ternary phase formation during the Pd-GaAs reaction have been studied by application of transmission electron microscopy (TEM) and Rutherford backscattering (RBS) techniques. The TEM images show that the first product phase, “phase I”, forms during deposition of Pd onto (100) GaAs and exhibits the preferred orientation [0001]I ∼ // [011]GaAs. In the presence of unreacted Pd, the second phase, “phase II”, nucleates at large-angle grain boundaries in the phase I film as the annealing temperature increases above ∼ 250°C Energy dispersive analysis of x-rays and RBS suggest that both phases I and II have nominal compositions in the range of Pd3GaAs to Pd4GaAs.
Non-Alloyed Ohmic Contacts to n-GaAs Using Epitaxial Ge Layers
Authors: Sawada T. , Chen W. X. , Marshall E. D. , Kavanagh K. L. , Kuech T. F. , Pai C. S. , Lau S. S. 
Published: March 2011

ABSTRACTAlloyed ohmic contacts (i.e. Au-Ge-Ni) to n-GaAs lead to non-planar interfaces which are unsuitable for devices with shallow junctions and small dimensions. In this study, the fabrication of non-alloyed ohmic contacts (via solid state reactions) is investigated. A layered structure involving the solid phase epitaxy of Ge using a transport medium (PdGe) is shown to produce low (1 — 5 × 10∼6Ω cm2) and reproducible values of contact resistivity. The resultant interface is shown to be abrupt by cross-sectional transmission electron microscopy.
Improved Ohmic Contacts to n-Type GaAs, Using Oiboride Diffusion Barriers
Authors: Shappirio Joel R. , Lux Robert A. , Finnegan John J. , Fox Donald C. , Kwiatkowski Joseph H. 
Published: March 2011

ABSTRACTOhmic contacts employing Au/Metal/Au/Ge/Ni (Metal=Ni or. TiB2) to n-type GaAs have been investigated. Alloying of the contacts, performed by both optical (rapid thermal) and strip heater methods, resulted in very low specific contact resistivities for the samples employing the TiB2 diffusion barrier. Such contacts are shown to be stable on aging at 350C for 180 hours.