bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion Beam Deposition of Materials At 40–200 Ev: Effect of Ion Energy And Substrate Temperature On Interface, Thin Film And Damage Formation
Authors: Herbots N. , Appleton B.R. , Pennycook S.J. , Noggle T.S. , Zuhr R.A.
Published: March 2011

Ion beam deposition (IBD), the process whereby magnetically analyzed ions are directly deposited on single crystal substrates, has been studied for 74Ge and 30Si ions on Si(100) and Ge(100). The effects of sputtercleaning prior to deposition and substrate temperature during deposition were investigated. Three analytical techniques were systematically used to obtain information on the deposited films: (1) Rutherford backscattering combined with ion channeling, (2) cross-section TEM, and (3) Seeman-Bohlin X-ray diffraction. In the energy range explored (40–200 eV), the width of the interface between the IBD film and the substrate was found to be always less than 1 nm. Each IBD layer was highly uniform in thickness and composition for deposition temperatures from 300 K to 900 K. Without prior sputter-cleaning and annealing of the Si(100) and Ge(100) substrates, no epitaxy was observed. UHV conditions were found to be a requirement in order to grow crystalline Si films presenting bulk-like density. This was not the case for Ge films which showed bulk-like density for IBD at higher pressures. Results on the first Si/Ge superstructure grown by IBD are also shown.
Ion Irradiation Induced Amorphous To Quasicrystalline Transformation: Composition Dependence In The Almn System
Authors: Lilienfeld D. A. , Nastasi M. , Johnson H. H. , Ast D. G. , Mayer J. W.
Published: March 2011

Multilayered Al84Mn16 films ion irradiated with Xe at room temperature transform into an amorphous phase. Subsequent Xe ion irradiation at 150C transforms the amorphous to the quasicrystalline phase. The quasicrystalline structure may be formed in the composition range of 91 atomic % Al to 80 atomic % Al.
Pulsed Laser And Ion Beam Surface Modification of Sintered, Alpha-Sic
Authors: More K. L. , Davis R. F. , Appleton B. R. , Lowndes D. , Smith P.
Published: March 2011

Pulsed laser annealing and ion beam mixing have been used as surface modification techniques to enhance the physical properties of polycrystalline α-SiC. Thin Ni overlayers (20 nm - 100 nm) were evaporated onto the SiC surface. The specimens were subsequently irradiated with pulses of a ruby or krypton fluoride (KrF) excimer laser or bombarded with high energy Xe+ or Si+ ions. Both processes are non-equilibrium methods and each has been shown to induce unique microstructural changes at the SiC surface which are not attainable by conventional thermal treatments. Under particular (and optimum) processing conditions, these changes considerably increased the mechanical properties of the SiC; following laser irradiation, the fracture strength of the SiC was increased by as much as 50%, but after ion beam mixing, no strength increase was observed.

High resolution cross-section transmission electron microscopy (X-TEM), scanning electron microscopy (SEM), and Rutherford backscattering techniques were used to characterize the extent of mixing between the Ni and the SiC as a result of the surface modification.
Some Characteristics of Al12Mo in Aluminum Annealed After Implantation with Molybdenum
Authors: Stephenson L. D. , Bentley J. , Benson R. B. , Hubler G. K. , Parrish P. A.
Published: March 2011

The characteristics of A112Mo formed in aluminum annealed after implantation with selected maximum molybdenum concentrations were examined by analytical electron microscopy techniques. The A112MO was isolated as the only precipitate in the microstructure for maximum as-implanted molybdenum concentrations up to 11 atomic percent. The morphology of the A112MO can be selected by choosing the maximum as-implanted molybdenum level over the same concentration range. A predominantly lamellar A112MO precipitate structure formed when aluminum was annealed at 550°C after implantation with maximum molybdenum concentrations in the range of 3.3 - 4.4 at.%. The orientation of the body centered cubic (bcc) A112Mo precipitate with respect to the face centered cubic (fcc) matrix can be expressed as (123)p || (002)m and [301]p || [310]m. An explanation for the experimentally observed orientation relationship was developed based on the characteristic relationships between the bcc A112MO precipitate and the fcc matrix. A continuous film of A112MO formed in the surface modified region when aluminum was annealed after implantation with maximum molybdenum concentrations in the approximate range of 8-11 at.%. The microstructure of the A112Mo film was found to depend on the annealing temperature. A granular film formed after annealing at 550°C whereas a mottled film formed after annealing at 400°C. Sequential annealing experiments revealed that the mottled film transforms to a granular film which indicates the mottled film is metastable.
Role of Chemical Disordering In Eleci3O Irradiation Induced Amorphisation
Authors: Luzzi D.E. , Mori H. , Fujita H. , Meshii M.
Published: March 2011

The electron irradiation induced crystalline to amorphous (C-A) transition was investigated in the Cu-Ti alloy system. As the transition is found to be dose dependent, the energy accumulated during the irradiation must make the crystal lattice unstable with respect to the amorphous state. In this paper, two possibilities for this energy accumulation, chemical disordering and the accumulation of point defects, is examined using the intermetallic compound CuTi2. Also, the effect of deviations from stoichiometry on the C-A transition is investigated in the compound CuTi. The Bragg-Williams long-rang order parameter, S, was found to decrease with electron dose. The rate of this decrease decreased with increasing temperature. At a critical temperature, the maximum obtainable degree of chemical disordering critically decreased. This critical temperature coincided with the critical temperature for the C-A transition, favoring the chemical disordering as the primary driving force. In CuTi, the C-A transition was hindered when there existed a Cu-rich deviation from stoichiometry.
A Comparative Study of The Crystallization of Ni-P Amorphous Alloys Produced By Ion-Implantation And Melt Spinning.
Authors: Hamlyn-Harris James , John D. H. St. , Sood D. K.
Published: March 2011

Implantation of 4OkeV P+ ions into high purity Ni was employed at room temperature to a dose of 3×10E17 ions/cm2 to produce an 1100 A thick amorphous surface alloy of Ni-14 wt% P. Commercially available melt spun metallic glass ribbons of nominal composition, Ni-il wt% P were used for comparison of crystallization behaviour studied with TEM and RBS techniques. The DTA analysis was employed to construct a TTT curve for the melt spun glass, which was then used as a guide for selecting time and temperature of crystallization of the implanted amorphous alloy. The melt implanted glass is found to be less stable and crystallizes more readily than melt spun glass of similar composition. A detailed study on nucleation and growth of crystallites, mode of crystallization and effect of surface proximity will be presented.
Transition Between Condensed Phases In Si And Ge
Authors: Turnbull David
Published: March 2011

The thermodynamic interrelation between the amorphous semiconducting (a-sc), the diamond cubic (c-sc) and the liquid metal (lm) states of Ge and Si is reviewed with especial emphasis on the question of the thermodynamic uniqueness of the a-sc state following its structural relaxation. The experience on the occurrence of the direct lm→a-sc transition and its reverse is surveyed and interpreted. This experience, in conjunction with the lm undercooling studies of Devaud and the author, indicates that the formation, in the metastable regime, of a-sc from lm results from preferential growth rather than preferential nucleation.
Anomalous Behavior During The Solidification of Silicon In The Presence of Impurities
Authors: Thompson Michael O. , Peercy P. S.
Published: March 2011

Nanosecond pulsed laser irradiation of silicon results in the melting of the surface with subsequent solidification from a crystalline substrate. In the presence of impurities or alloys, the solidification dynamics are greatly affected by the nature of the impurities. Five classes of materials have been investigated: amorphous Si, mutually soluble alloys, high solubility impurities, low solubility impurities, and compound forming materials. Solidification of each of these classes of materials is discussed. Several anomalous kinetic regimes are observed, including explosive crystallization, surface nucleation of solid, and internal nucleation of melt. These results are interpreted in terms of thermodynamic modifications of the melting temperature in the alloy regions.
Mos Circuits on Silicon—Boron Phosphide—Silicon Multilayers
Authors: Dumin D. J.
Published: March 2011

One approach to the fabrication of multiple silicon — insulator silicon layers that is compatible with existing silicon batch processing technology is to grow all of thelayers heteroepitaxially in a hydride reactor. We have grown multiple Si—Ins—Si layers using boron phosphide as the insulator. Up to 4 layers of BP—Si havebeen grown on silicon substrates and up to 2 layers have been grown on SOS substrates. MOS integrated circuits have been fabricated on the various Si layers. In general, the individual device quality and the performance of the ICs was lower as the number of layersincreased, however, even ICs fabricated on 4 layers of Si—BP—Si had characteristics comparable with SOS ICs. The growth process for production of the multiple heteroepitaxial films will be described. The characteristics of the ICs will be correlated with the film properties. Other possible candidates for insulators will be discussed.
Gallium Arsenide Layers Grown By Mbe on Germanium Islands on Insulator
Authors: Takai M. , Kodama Y. , Tanigawa T. , Kobayashi K. , Gamo K. , Namba S.
Published: March 2011

Local variation of photoluminescence (PL) spectra for MBE GaAs grown on an insulating substrate with Ge-islands interface layers, prepared by zone melting recrystallization, has been investigated. The GaAs layers on the single crystalline Ge islands emit PL, the intensity of which was almost comparable to that of the GaAs layers on bulk Ge, while by a factor of 50 lower PL intensity was observed for the GaAs layers on Si02. PL spectra were found to show peak shifts due to the band-gap variation near the interface layer of GaAs, which was in good agreement with the residual strain obtained by microprobe Raman scattering for underlying Ge islands.
LPCVD Tungsten Deposition on Porous Silicon for Formation of Buried Conductors
Authors: Tsao S. S. , Blewer R. S.
Published: March 2011

We report results on the feasibility of forming buried conductors under single crystal silicon using low pressure chemical vapor deposition of tungsten on the internal surfaces of porous silicon. The infiltration of tungsten into the pores depends on the porous silicon porosity, and on tungsten deposition process parameters such as deposition duration, total deposition pressure, and carrier gas species. The resulting tungsten-porous silicon layers were characterized by transmission and scanning electron microscopy, by Rutherford backscattering and x-ray spectroscopy and by four-point probe resistivity measurements.
Effect of Annealing on the Structure of Buried SiO2 Layers Formed By Elevated Temperature High Dose Oxygen Implantation
Authors: Krause S.J. , Jung C.O. , Wilson S.R. , Lorigan R.P. , Burnham M.E.
Published: March 2011

Oxygen has been implanted into Si wafers at high doses and elevated temperatures to form a buried SiO2 layer for use in silicon-on-insulator (SOI) structures. Substrate heater temperatures have been varied (300, 400, 450 and 500°C) to determine the effect on the structure of the superficial Si layer through a processing cycle of implantation, annealing, and epitaxial growth. Transmission electron microscopy was used to characterize the structure of the superficial layer. The structure of the samples was examined after implantation, after annealing at 1150°C for 3 hours, and after growth of the epitaxial Si layer. There was a marked effect on the structure of the superficial Si layer due to varying substrate heater temperature during implantation. The single crystal structure of the superficial Si layer was preserved at all implantation temperatures from 300 to 500°C. At the highest heater temperature the superficial Si layer contained larger precipitates and fewer defects than did wafers implanted at lower temperatures. Annealing of the as-implanted wafers significantly reduced structural differences. All wafers had a region of large, amorphous 10 to 50 nm precipitates in the lower two-thirds of the superficial Si layer while in the upper third of the layer there were a few threading dislocations. In wafers implanted at lower temperatures the buried oxide grew at the top surface only. During epitaxial Si growth the buried oxide layer thinned and the precipitate region above and below the oxide layer thickened for all wafers. There were no significant structural differences of the epitaxial Si layer for wafers with different implantation temperatures. The epitaxial layer was high quality single crystal Si and contained a few threading dislocations. Overall, structural differences in the epitaxial Si layer due to differences in implantation temperature were minimal.
Formation of Silicon on Insulator Structures By Implanted Nitrogen
Authors: Nesbit L. , Stiffler S. , Slusser G. , Vinton H.
Published: March 2011

The formation of a silicon-on-insulator (SOI) structure by implanting a high dose of N+ ions to form a buried Si3N4 layer is studied by transmission electron microscopy (TEM) and by secondary ion mass spectroscopy (SIMS). The SOI structure is formed by implanting silicon wafers with 7.5x1017 N+ ions/cm2 at 160 keV and at wafer temperatures of 400, 500, or 600°C. The implanted wafers are subsequently annealed at 1200°C for times ranging from 10 minutes to 2 hours. The microstructures and nitrogen distributions of the asimplanted and post-annealed wafers are examined in order to elucidate the development of the final microstructure.
Study of Dose and Dose Rate in the Implantation of Nitrogen Isotopes Into Si(100)
Authors: Namavar F. , Budnick J.I. , Fasihuddin A. , Sanchez F. H. , Hayden H. C.
Published: March 2011

In this paper we address the issue of the dependence of Si3N4 formation on dose dose rate, and target temperature for high dose (up to 3 X 1018 N/cm2) implantation of nitrogen isotopel into Si targets. RBS results for high current (I≈ 30μ/cm2) and room temperature nitrogen implantations indicate that the nitrogen profile and the reduction of the backscattering signal from Si generally appear to be Gaussian. The nitrogen concentration exceeds Si3N4 stoichiometry at the higher doses. Read Camera results indicate the formation of polycrystalline α-Si3N4 and polycrystalline silicon for samples implanted at room temperature and annealed at 1200°C for 2 hours in a 10 Torr vacuum system. For samples implanted at 350 °C and annealed, there is evidence of crystalline α-Si3N4 with fiber texture structure.

For low current (〈1 °A/cm2) and room temperature implantation, RBS indicates the formation of a layer whose N/Si ratio is the same as that of Si3N4. Furthermore, the nitrogen profile and the reduction of the Si backscattering signal appear flat. These results suggest that a uniform layer of Si3N4 can be produced providing the supply of nitrogen does not exceed the diffusion rate of nitrogen in compounds formed during implantation.
Thermal Stress During Zone-Melting-Recrystallization of Silicon on Insulator Films: The Origin of Subboundaries and In-Plane Orientation of SOI
Authors: Gibson J.M. , Pfeiffer L.N. , West K.W. , Joy D.C.
Published: March 2011

The effect of thermal stress during zone-melting recrystallization of silicon on insulator films is considered. New experimental results from graphite-strip heated films are drawn upon. It is found that low-angle grain boundaries exhibit an inverse dependence between spacing and tilt angle. This is explained semiquantitatively by a model in which thermal stress induced film buckling is responsible for the existence of low-angle grain boundaries. It is also suggested that the predominance of the <100> orientation in these films is partly due to thermal stress and the elastic anisotropy of silicon. Thus thermal stress is proposed as the origin of the two major features of zone-melted films.
Integration of Semiconductor and Magnetic Bubble Devices: Soi on Garnet
Authors: Greve D.W. , Kryder M.H. , Rasky P.H.L.
Published: March 2011

Silicon on insulator (SOI) technology makes it possible to fabricate semiconductor devices on foreign substrates. In this paper, we present results for a process in which fieldeffect transistors are fabricated in recrystallized polysilicon on a magnetic bubble substrate. We report on the characteristics of the field effect transistors and the effect of the necessary processing steps on the magnetic properties of the substrate. A memory constructed in this hybrid technology would have very high density, multiple detectors for high speed, and direct logic level outputs.
Fabrication Process, Application and Future for An Elemental Level Vertically Integratedcircuit (Elvic)
Authors: Enomoto Tadayoshi
Published: March 2011

A new double-layered stacked LSI fabrication process has been developed for the purpose of realizing short fabrication turn-around time, high fabrication yield and high integration density. This process, which is named “Elemental Level Vertical Integrated Circuit (ELVIC)” technology, puts 2 convenfionally made LSI chips face to face andbonds them by thermal compression. The process includes, in addition to the conventionalLSI fabrication process, vertical interconnection (VI) formation in the upper and lower LSI layers, planarization of both upper and lower layer surfaces, and inter-level connections using pressure and heat. In the experimental version, about 52,000 10 x 10 μm2 Au-on-Ti VIs were connected on a 5 x 5 mm2 chip. Each pair of mated VIs is measured for tensile strength of 4 mg force. A 2-layer, 31-stage inter- CMOS/bulk ring oscillator consisting of p-channel MOSFETs on the upppr layerand nchannel MOSFETs on the lower layer has been built. Propagation delay time per stageis 1.86 nsec at the supply voltage of 5 V. ELVIC technology can produce a variety of benefits such as high production yield, doubling integration density, latch-up free CMOS LSIs, radiation damage free LSls, multi-function, and complete mixing of bipolar, CMOS andGaAs technologies.
Vertical Bipolar Transistors and a Merged 3–D Vertical Bipolar—Mos Device in Recrystallized Polysilicon
Authors: Sturm J.C. , Gibbons J.F.
Published: March 2011

The minority carrier properties of shaped—beam laser-recrystallized polysilicon films have been studied, leading to the successful fabrication of vertical bipolar transistors in these films and to the demonstration of a novel three—dimensional mergedvertical bipolar—MOS device. Experiments with lateral transistors established a minority carrier diffusion length of 4 μm in p—type recrystallized films. Vertical bipolar npn transistors with a base—width of 0.2 μm were fabricated in 0.75–μm—thick films using a polysilicon emitter technology. The strong dependence of the gain of the transistors on hydrogen annealing steps is described. With an Ar:H plasma anneal to decrease base—emitter space—charge region recombination, a common—emitter current gain of 100 was possible. The bipolar transistor technology was then used to develop a 3—D fourterminal merged verticalbipolar—MOS device in a recrystallized film. It consists of the three terminals of a bipolar transistor plus a fourth underlying terminal which serves to switch the collector current on or off. A simple model for the device is presented.
Latchup Free Lateral Cmos on Laser Recrystallized Silicon
Authors: Sritharan S. , Solanki R. , Collins G. J. , Fukumoto J. , Szluk N. , Ellsworth D.
Published: March 2011

Latchup free CMOS devices have been fabricated by forming PMOS transistors in a 0.5μm thick laser recrystallized silicon layer. This recrystallized layer is isolated fram the bulk wafer by a lμm thick oxide layer. The NMOS transistors were fabricated both in the bulk wafer in the region which was used as the recrystallization seeds, as well as in the recrystallized silicon layer itself. Ring oscillators fabricated with 3μm channel length using a bi-layer lateral CMOS structure show a naninal delay of 1.7ns/stage. The MOS devices fabricated in the recrystallized silicon show low subthreshold leakage current, and surface electron and hole mobilities of 580cm2/V.s and 210cm2/V.s respectively.
Leakage Currents in P-Channel Accumulation Mode Tft's
Authors: Khan B.A. , Marshall T. , Arnold E. , Pandya R.
Published: March 2011

We have fabricated accumulation mode MOSFETS in poly-silicon thin films and studied the effect of passivation of the leakage currents in these devices. We have used C-V measurements ot determine the effective doping concentration and depletion layer widths in the passivated and unpassivated devices. We find that passivation reduces the effective doping concentration and therefore increases the depletion layer width. Although this change in effective doping concentration is small (less thean a factor of 2), the increase in depletion layer width is sufficient to pinch off the passivated device but not the unpassivated one. This leads to the dramatic reduction in leakage currents after passivation.
On The Rapid Thermal Sintering Of Thin Amorphous Si-Metal-Si Structures
Authors: Natan Menachem
Published: March 2011

The development of rapid thermal annealing (RTA) or sintering (RTS) techniques for processing of Si and compound semiconductor metallizations also opens a new avenue for investigations of the initial stages of high-temperature, solid state reactions in thin amorphous multilayers. Of particular interest in this regard are the nucleation and early growth of silicides. In this study we suggest a method to prepare large numbers of specimens for TEM, using deposition of Si/metal/Si tri layers on electron microscope grids and annealing the grids in an RTA system. The method enables quick determination of first silicide phases, nuclei shape and density, relative nucleation and growth rates and, for some systems, the diffusing species. Seven widely used metals are investigated: Co, Cr, Nb, Ni, Mo, Ti, and Ta. The first silicide phases determined from electron diffraction patterns are listed and compared to first phases reported in longer furnace annealings. TEM cross sections of reacted Si/Ta/Si and Si/Nb/Si show two different growth morphologies, which are discussed in terms of main diffusing species in a proposed model.
Sequence Of Phase Formation In Ni/Ai Contrasted With Ni/Si
Authors: Colgan E. G. , Mayer J. W.
Published: March 2011

We have investigated the interactions of Al/Ni, NiAl3/Ni, and Ni2Al3/Ni thin films between 350 and 500°C. Sequential layer deposition and coevaporation were used to prepare the films which were then vacuum annealed and analyzed by Rutherford backseat tering and X-ray diffraction. Initially, NiAl3 is formed, followed by the more Ni-rich phases. All four intermetallic phases were formed.
Alumina-Ti Interface Reactions Studied By AES And UPS
Authors: Lefakis H. , Liehr M. , Rubloff G. W. , Ho P. S.
Published: March 2011

The interaction of Ti with A12O3 under UHV conditions has been studied by AES and UPS. Ti was deposited by iterated and successively thicker evaporations (up to a total thickness of 91 Å) under UHV conditions onto the alumina substrate at room temperature. The oxide substrate was grown on Al/Si(111) in an adjacent VHV preparation chamber. The last deposition was followed by in situ annealing. It was found that, contrary to indications of thermodynamic considerations using bulk equilibrium data, Ti interacts strongly with alumina at room temperature, dissociating it to metallic Al and forming TiO2 at the interface. This reaction is limited, resulting in an interface width of ∼10 Å and allowing subsequent evaporations to homogeneously cover the products. Annealing to 500°C does not produce any evidence of outdiffusion or extensive interface reactions, implying that the interface oxide is stable and an effective barrier to Al (and/or Ti) diffusion up to this temperature.
Reaction Kinetics, Stress And Microstructure In Titanium-Copper-Titanium Thin Films
Authors: Hu C. -K. , Gupta D. , Wetzel J. T. , Ho P. S.
Published: March 2011

Interdiffusion, reactions and microstructure in Ti-Cu-Ti trilayer thin films deposited on silicon wafers have been investigated by Rutherford backscattering, and cross-sectional TEM techniques in the temperature range of 350 to 500 °C. The formation of intcrmetallic compounds was found to be symmetric at both interfaces in Ti-Cu-Ti film package. TiCu compound formed first at low temperature and was followed by TiCu3 at higher temperatures. The stress in Ti-Cu film has also been measured in-situ as functions of both temperature and annealing time by thin fused quartz bending-cantilever beam technique. The stress in metallic Ti-Cu film couple on fused quartz was tensile. The stress increased as both annealing time and temperature increased and followed a parabolic relationship with time due to the growth of the intermetallic compound TiCu3 It was possible to calculate stress in the TiCu3 layer from the changes of stress in the bilayer thin film. The stress in TiCu3 was computed to be at about 3 times larger than the stress in the unreacted Ti-Cu thin film couple.
Formation of New Interfacial Phases in Bimetallic Thin Film Couples Studied by in Situ Annealing X-ray Diffraction
Authors: Vandenberg J. M.
Published: March 2011

Interfacial reactions in bimetallic thin films have been studied by in-situ glancing angle X-ray diffraction which enables us to monitor all stages of the interface reaction in the temperature range 35 °-950° C Results are presented on new phase formation in evaporated Ag-Al and Cu-Al thin film couples, sputtered bimetallic Nb-Sn and Nb-Pb films and magnetic alloy films. New phases as well as phase transitions which are not known to exist in the bulk phase diagrams, were observed. These results provided evidence that phases other than those predicted by the first nucleation rule, grow during the initial metal-metal thin film interface reaction.
Dominant Moving Species in the Formation of Amorphous HfNi By Solid-State Reaction
Authors: Cheng Y.-T. , Nicolet M.-A. , Johnson W. L.
Published: March 2011

The displacements of Mo, Zr and Pd markers have been monitored by backscattering of MeV He+ to study the growth of the amorphous HfNi phase by solid-state reaction. We find that the Ni is the dominant moving species in this reaction.
Homogeneous Al-Ti and Al-Ti-Si Thin Alloy Films
Authors: Dirks Albertus G. , Tien Tien , Towner Janet M.
Published: March 2011

The microstructure and properties of thin films depends strongly upon the alloy composition. A study was made of the metallurgical aspects of homogeneous Al alloy films, particularly the binary Al-Ti and the ternary Al-Ti-Si systems. Electrical resistivity, grain size morphology, second phase formation and electromigration have been studied as a function of the alloy composition and its heat treatment.
Ion-Beam Induced Silicide Formation: Markers and Moving Species
Authors: Hung L. S. , Mayer J. W.
Published: March 2011

The moving species in near-noble metal suicide formation was investigated using embedded markers and Rutherford backscattering. With thermal annealing of Ni-silicides, Ni is the dominant diffusing species while in ion-induced reactions both Ni and Si diffuse across the suicide. This difference in behavior is not a result of the formation of amorphous Si during ion irradiation nor is it caused by release of Si. We propose that the diffusion of Si is associated with the formation of defects in the suicide layer generated within the collision cascade.
Formation of GaAs Ohmic Contacts by Using Ion Beam Mixing
Authors: Furukawa S. , Asano T. , Fukada T. , Ishiwara H. , Tsutsui K.
Published: March 2011

Ion beam mixing effects on metals and highly doped semiconductors on GaAs for formation of ohmic contacts have been studied. In this study, we have principally selected Pt as metal and Ge as semiconductors electrodes for GaAs. In Pt/GaAs system, we observed alloying phenomena induced by Si+, Ar+, Ge+ ion mixing effects. The amount of GaAs reacted with Pt was found to be proportional to the mass of the incident ions for constant dose. Concernig with the formation of ohmic contacts, only in the case of Si implantation through Pt films, the conversion from Schottky- to ohmic-contact was observed due to ion beam mixing effects. In Ge/GaAs system, we observad the solid state epitaxy for implanted Ge layer by the first annealing at 450°C in the two step annealing, but no activation of the implanted species. For activating implanted species, the second annealing at 800°C was effective. Concerning with the formation of ohmic contacts, we observed that the ohmic I-V characteristics for Ge/GaAs system could be obtainable when the following conditions were satisfied at the same time: 1) high dose implantation of As+ into Ge layer, 2) low dose implantation of Si into Ge/GaAs boundary and 3) relatively short period annealing in the second annealing step. From such study, it is concluded that ion beam mixing in conjunction with rapid annealing would be most promising for forming stable and reproducible ohmic contacts.
Ion Beam Mixing Of Marker Atoms in Mo and Ru and Heat of Mixing
Authors: Kim S.-J. , Paine B. M. , Nicolet M-A. , Averback R. S.
Published: March 2011

The effect of the heat of mixing, ΔHm, on the ion beam mixing of marker systems was studied. The matrices for tne experiment were Mo and Ru, and marker atoms were Ti, Cr, Mn, Ni, Hf, Ta, Pt, and Au. These markers and matrices have heat of mixing ranging from +65 to -227 kJ/mol. Irradiations were done with 300 keV Kr at 77 and 300 K, with room temperature backscattering spectrometry analysis. There was no correlation between the mixing results and heat of mixing, which is consistent with the idea of ion beam mixing of dilute marker system.
Effects of Thin Interposing Layers on The Epitaxial Growth of FeSi'2 on Silicon
Authors: Cheng H. C. , Yew T. R. , Chen L. J.
Published: March 2011

Thin interposing Ni or Co layers between Fe thin films and Si have been shown to be very effective in inducing the growth and improving the quality of epitaxial FeSi2 on silicon. The formation of a transition layer with graded concentration is conceived to facilitate the epitaxial growth of FeSi2 on silicon. The thin interposing layer scheme may be extended to promote the epitaxial growth of a number of refractory suicides on silicon.
High Spatial-Resolution Analysis of Lateral Suicide Formation
Authors: Barbour J. C. , Batson P. E. , Mayer J. W.
Published: March 2011

Thin-film Ni-Si lateral-diffusion couples were annealed at 450°C for 12 hours to cause formation of the suicide phases: Ni3Si, Ni5-Si2, Ni2Si, and NiSi. Scanning transmission electron microscopy (STEM) was used to investigate the suicide growth. The mechanism of Ni transport to the growth front was shown to be bulk phase diffusion, as evidenced by a bulk phase concentration gradient of 0.03 atomica Ni/nm in the NiSi phase. The transition from thin film kinetic behavior to bulk couple kinetic behavior was found to be greater than 200 nm. The absence of the Ni3Si2 phase in the lateral-diffusion couple was attributed to a nucleation barrier. An excess amount of Ni in the Ni2Si phase at the Ni2Si-NiSi interface indicates the interdiffusivity is lower in NiSi than in Ni2Si, thereby limiting Ni diffusion out of the Ni2Si phase.
Competing Initial Reactions at Transition-Metal/Silicon Interfaces
Authors: Rubloff G. W.
Published: March 2011

The process of suicide formation by contact reaction at metal/Si interfaces normally involves rather uniform motion of the growth fronts which separate metal, suicide, and Si regions, as has been observed for suicide growth in many transition-metal/Si systems. At lower temperatures, however, the reaction behavior can be complicated significantly by the presence of other material reactions which may compete with interfacial suicide formation. For refractory metals, strong interfacial mixing over considerable depth (∼ 100 Å or more) is observed at temperatures too low for the normal inlerlacial suicide formation process to contribute; the highly nonuniform character of this reaction, as shown by ion scattering and TEM studies, suggests that other material reactions (e.g., grain boundary diffusion) must dominate the interfacial chemistry at low temperature. In a similar way, anomalous and nonuniform reaction behavior during the low temperature deposition of initial transition metal layers on Si apparently involves surface diffusion processes which are faster than inlerlacial suicide formation.
Characterization of CDTE Films, Useful In All Thin-Films Solar Cells. I. CD Vacancies And Photoluminescence Spectra
Authors: Figueroa J. M. , Vazquez-Lopez C. , Sanchez-Sinencio F. , Mendoza-Alvarez J. G. , Zelaya O.
Published: March 2011

Polycrystalline CdTe films were grown by a hot-wall-close space vapor transport technique. In-doped CdTe films were grown onto conductive tin-oxide glass substrates. In order to produce Cd-vacancies, the films were photocorroded using the electrochemical arrangement reported by C. Vazquez-Lopez et al [4]. CdTe films were photocorroted during different times of illumination. Photoluminescence spectra of these films showed that the peak at 1.55eV grows with the photocorrosion time. Our results indicate that the 1.55 peak is associated to Cd-vacancies which are produced during the photo-corrosion process.
Interactions Of Evaporated Nickel And Silicon Thin Films
Authors: Zheng L. R. , Hung L. S. , Mayer J. W.
Published: March 2011

Interactions of evaporated Ni and Si thin films were investigated by a combination of backseat tering spectrometry and transmission electron microscopy. The presence of amorphous Si has no significant effects on Ni2Si and NiSi formation, but it drastically lowers the formation temperature of NiSi. Experiments with evaporated thin markers established that Ni is the dominant diffusing species in the growth of the three suicides. The stability of NiSi was examined by sequential evaporation of Ni34Si66 and Ni50Si50 thin films both on Si(100) and on evaporated Si substrates. The results showed that NiSi2 grows at the expence of NiSi when the stucture is in contact with evaporated Si, while it dissociates into NiSi and Si when in contact with single crystal Si.
Formation of Silicon Nitride films Newly Developed by the Ion and Vapour Deposition Method
Authors: Sugawara F. , Ajioka T. , Ichikawa F. , Ushio S.
Published: March 2011

The Ion and vapour deposition method (IVD method) has been used for the first time to form silicon nitride films. Silicon nitride formation using IVD method, which consists of a nitrogen ion implantation and a simultaneous electron beam evaporation of silicon, has been confirmed.

These silicon nitride films formed by IVD method have been characterized using FTIR, ellipsometry and AES analyses. It has been observed that these IVD silicon nitride films characteristics are sensitive to the nitrogen ion implantation conditions and the silicon evaporation rate.

Applications of these IVD films to selective oxidation have exhibited a good resistance to oxidation. It has also permitted the bird's beak to be reduced.
AES and XPS Studies of the Chemical Effects at the Magneto-Optic/Dielectric Interface
Authors: Coulman D. , Anthony T.
Published: March 2011

The chemical stability of magneto-optic structures of sputter-deposited SiO, SiO2, or Si3N4/TbFeCo/SiO, SiO2, or Si3N4 was studied in detail. The degradation of the magnetic properties of the TbFeCo film have been correlated with the oxygen content within the film as determined by Auger and RBS. Auger and XPS depth profiles have revealed that for oxygen containing dielectrics the preferential oxidation of terbium is responsible for the observed differences in coercivity. Reduction of the dielectric at the SiO/TbFeCo interface, along with diffusion of oxygen into the RETM film, have been observed. The Si3N4/TbFeCo structure shows no evidence of either interdiffusion between the layers or oxidation of the TbFeCo film. From our investigation we conclude that Si3N4 is a superior dielectric for quadri layer structures in magneto-optic media.
Modified Oxide Properties from Dopant Effects at the Si-SiO2 Interface
Authors: Jackson Michael A. , Salvati Lawrence , Chin Roland L. , Anderson Wayne A.
Published: March 2011

Both thin, 60→140Å thick, and native oxides on As and P doped Si were studied via null ellipsometry and angle resolved ESCA. Results showed higher oxide growth rates to occur for higher surface concentrations of a given dopant. For similar surface concentrations, P-doped samples oxidized faster than As-doped, in both cases. Exact oxidation rates were not determined as results indicate that stoichiometric variations and oxidation of carbon contamination influence thickness determination of these oxides.
MPI/MS Studies of Thin Film Deposition Processes: Methyl Production from Trimethylgallium Decomposition and the Effect of Added Hydrazine
Authors: Squire D. W. , Dulcey C. S. , Lin M. C.
Published: March 2011

The low pressure pyrolysis of alkylmetals on resistively heated substrates was studied using multiphoton and electron ionization mass analysis. The activation energy for the production of gas phase methyl radicals from the decomposition of trimethylgallium under single collision conditions was found to be 26 ± 3 kcal/mol, which is to be compared to 13 ± 2 kcal/mol previously observed for trimethylaluminum. No evidence could be found for any surface radical reactions leading to the production of CH4 or C2H6. A proposed deposition mechanism accounting for these observations was tested by pyrolyzing trimethylgallium in the presence of hydrazine. No change in methyl signal was observed, supporting the theory that radical reactions do not occur on the surface under the conditions employed.
Effect of Argon and Hydrogen on Deposition of Silicon from Tetrachlorosilane in Cold Plasmas
Authors: Manory R. R. , Avni R. , Grill A.
Published: March 2011

The roles of Ar and H2 on the decomposition of SiCl4 1n cold plasma were Investigated by Langmulr probes and mass spectrometry. Decomposition of the reactant by Ar only has been found to be very slow. In presence of H2 in the plasma SiCl4 is decomposed by fast radical-molecule reactions which are further enhanced by Ar due to additional 1on-molecule reactions in which more H radicals are produced. A model for the plasma-surface Interactions during deposition of pC-S1 1n the Ar + H2 + SiCl4 system is presented.
Formation of Silicides by Rapid Thermal Annealing Over Polycrystalline Silicon
Authors: Narayan J. , Stephenson T. A. , Brat T. , Fathy D. , Pennycook S. J.
Published: March 2011

The formation of titanium suicide over polycrystalline silicon has been investigated after rapid thermal annealing treatment in nitrogen and argon ambients. After rapid thermal annealing 300 Å thick titanium overlayer at 900°C for 10 seconds, the sheet resistance of about 3 Ω/□ was achieved, which decreased to 2 Ω/□ after 1100°C / 10s treatment. The TiSi2 Phase was found to be stable after RTA treatments up to 1100°C /10s with no or negligible migration of titanium along the grain boundaries in polycrystalline silicon. In the nitrogen ambient, an external layer (titanium rich, mixture of titanium oxide and nitride) was observed to form after the RTA treatment, but the surface was found clean in the argon ambient.
Mechanical Properties of Metallic Films on Sapphire
Authors: List F. A. , Mckee R. A.
Published: March 2011

A knowledge of interfacial mechanical properties is of considerable importance to the areas of oxidation, corrosion, metallization, and composite materials. We have developed an experimental apparatus capable of simultaneous measurements of elastic and anelastic properties of materials in controlled atmospheres (10-6 to 104 Pa) from 25 to 1000°C. The apparatus employs the technique of dynamic reasonance in which a material's mechanical resonance spectrum can be determined over a range 102 to 105 Hz with resolution ±0.001 Hz. This resolution has enabled us to determine the mechanical properties of films as thin as approximately 10 nm.

We shall present resonance results for thin films (∼100 nm) of nickel and gold on sapphire substrates. These results suggest that nickel films on sapphire are adherent, i.e., cyclic strain is continuous at the film-substrate interface, over a range of temperature about the film growth temperature; whereas gold films show nonadherent behavior at all temperatures studied.
Electromigration Resistance of Multilayer Aluminum/Titanium Interconnects
Authors: Finetti M. , Ronkainen H. , Blomberg M. , Suni I.
Published: March 2011

We have investigated the electromigration resistance of Al-Si/Ti multilayer interconnects. For comparison Al-Si and Al-Si/Ti/Al-Si films were also prepared. The linewidths ranged between 1.6 and 5, um. A temperature-ramp resistance analysis was applied at direct wafer level, to detect electrically transport of material and derive the electromigration kinetic parameters in test vehicles with different geometries.
Low Temperature Oxidation and Spalling of Electrodeposited and Vapour-Deposited Copper
Authors: Fisher Robert M. , Martin Bret , Cannon Rowland M.
Published: March 2011

Thermal cycling of silicon solar cells heated with incandescent light or using an in-situ heating stage on an optical microscope caused unexpectedly rapid oxidation of the electrodeposited copper current collecting grid. Unusually fine buckling and spal ling of the oxide film also occurred at temp. as low as 180°C. These effects appear to stem from the very fine columnar grains and high defect content of the copper ribbons and some Cl residue from the electrolyte. With vapour-deposited Cu, similar relatively rapid oxidation and spalling were also observed. Origins of the high oxidation rates, the large compressive stresses within the oxide and the low-temperature spalling are discussed.
Magnetic Eiaxaticn and Structural Transfor4Aticn in Metallic Glasses
Authors: O'Handley R.C.
Published: March 2011

Current understanding of the local atomic structure of amorphous materials is reviewed. Sane results of probing short—range order by selected techniques are cited to illustrate the degree of uniformity that exists on a local scale. Observations of phase separation and phase changes are described with particular emphasis on a temperature driven, reversible transformation of the local structure observed magnetically in several cobalt—base glasses. The manifestations and implications of such transformations within the glassy state are examined. Several examples pointing to quasi—crystalline and to non—crystalline (non—space filling) local structures are given.
Magnetic Domain Structures in Cerium—Doped Fe80B20, Fe80B16Si2C2, and Fe78B13Si9 Glassy Ribbons
Authors: Canright G. S. , Kroeger D. M.
Published: March 2011

The addition of cerium in parts—per—million quantities has been shown to be effective in inhibiting the annealing embrittlement of melt—spun amorphous ribbons [1]. The effects of cerium doping on magnetic domain structures are reported in this paper. Domain structures have been observed using the Bitter colloid technique on the free surfaces of asquenched ribbons, as well as on both surfaces of ribbonswhich have been thinned by electropolishing. In the binary and quaternary alloys, the optimum (in terms of mechanical properties) cerium content gives ribbons which are apparently free of quenched—in stresses, since they lack the commonly observed “maze domains” which are found for both undoped and excessively doped ribbons. In contrast, the ternary alloy, which shows little decrease in annealing embrittlement versus doping, is free of maze domains in the as—quenched condition, with or without doping. The effect on the former two alloys is interpreted in terms of enhanced stress—relief during the quench.
Composition Dependence of Magnetic Shielding Properties for Amorphous Ribbons (FeNi)78Mo4B17Si
Authors: Huang Der-Ray , Dow Wen-Huu , Yao Pei-Chih , Hsu Shu-En
Published: March 2011

Amorphous ribbons (FeNi)78Mo4B17Si, made by melt—spinning technique were prepared as magnetic shielding materials. Cylindrical shields (~0.05mm thick) were fabricated by wrapping ribbons on 20cm long pyrex tubes with 45mm diameter. DC and AC (60Hz, 400Hz, 800Hz, 1 kHz) magnetic shielding data were obtained by following the modified ASTM (A698–74) procedure. For DC magnetic fields, Ni—rich shields showed maximum shielding values at lower applied fields (0.1 0e~l 0e), while Fe—rich shields showed maximum shielding values at higher applied fields (1~5 0e). For AC magnetic fields, the magnetic fields, the magnetic shielding effectiveness was also influenced by skin effect at shield' surfaces. By comparing the data to calculations from shielding theory, there is about 8% magnetic shielding effectiveness induced by skin effect at 1 kHz.
Characterization of Inhomogeneities in Amorphous Superconductors
Authors: Alp Esen E. , Malik S.K. , Lepetre Y. , Montano P.A. , Shenoy G.K.
Published: March 2011

The structure and superconducting properties of rapidly quenched Zr—Ni and Zr—V alloys have been studied by XRD,EXAFS spectroscopy,TEM,electron diffraction,ED, electrical resistivity and ac susceptibility measurements. Amorphous Zr66Ni34 ribbons quenched with different cooling rates were also examined by flux pinning measurements. Characteristic differences are observed in the flux pinning mechanisms of microcrystalline and amorphous samples. The temperature dependence of upper critical fields have been measured down to 0.4 K and the results are analyzed in terms of WHH theory.
Magneto—Optical Properties of Amorphous TbFe Alloys
Authors: Mansuripur M. , Ruane M. , Wolniansky P. , Chase S. , Rosenvold R.
Published: March 2011

Hysteresis loops and anisotropy energy constants are measured in a magneto—optical system that combines Kerr rotation and ellipticity to enhance signal strength. Temperature dependence of the polar Kerr effect is compared with the magnetization of the iron subnetwork in the mean—field approximation and good agreement is obtained. Perpendicular magnetic anisotropy is studied by magneto—optical methods, yielding the first two coefficients of the series expansion of anisotropy energy in terms of the angleof deviation from the easy axis.
Crystallization and Magnetic Studies in Melt-Spun Fe77Nd15−xRxB8 Ribbons
Authors: Rao K.V. , Malmhall R. , Gudimetta Krishna , Hadjipanayis G.C.
Published: March 2011

Low field (∿5 Oe)Magneto-Thermo-Gravimetric technique has been used to study the effects of substitution of Nd with Y, Gd, and Dy in melt-spun Fe77Nd15B8 alloys, and also to monitor the changes in the magnetic properties on heat treatment to achieve optimum magnetic hardening in these alloys. From VSM-measurements preliminary studies of the effect of substitution for Nd on the hysteretic loops are presented.
Transport Property Studies on Icosahedral Systems: Rapidly Quenched Al-V, Al-Mn, AND Al-Fe-Mn.
Authors: Rao K. V. , Karpe N. , Malmhall R. , Astrum H. U. , Chen H. S.
Published: March 2011

We report the first Hall, and electrical resistivity study on rapidly quenched icosahedral Al-based alloys. The Hall coefficient is found to be negative and remains so for i(Al-Mn) alloys even for higher Mn concentrations. The magnitude and temperature coefficient of the electrical resistivity behaviour in these alloys is similar to those observed for amorphous metallic alloys. Thus, the conduction process in i(Al-based alloys) is essentially electronic but with a carrier mobility an order of magnitude smaller than that known for crystalline aluminium.