bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Defects in Proton-Implanted
GaAs
Authors: Jenkinson H. A. , Maracas G. N. , O'Tooni M. , Sarkis R. G. 
Published: March 2011

ABSTRACTStudies have been made of n+-GaAs implanted with 300 keV protons
to fluences of 1014−1016/cm2. Electrical
studies included I–V analysis, DLTS, and thermally stimulated current
measurements made on implanted FET-like structures fabricated from MBE GaAs
epi-layers. Optical infrared reflectance spectra and high resolution
transmission electron micrographs were obtained for as-implanted material
and for specimens annealed at 300 °C and 500 °C. Results show as-implanted
material can be characterized by a band of traps lying about 0.2 eV below
the conduction band with a relatively uniform distribution throughout the
implanted region. Thermal processing causes a significant alteration in the
density and distribution of these defects.
Improving the Quality of a Heteroepitaxial CaF2
Overlayer by Rapid Post Annealing
Authors: Pfeiffer Loren , Phillips Julia M. , Smith T.P. , Augustyniak W. M. , West K. W. 
Published: March 2011

ABSTRACTWe show that post anneals of short duration at high temperature can markedly
improve the quality of CaF2 films grown by molecular beam epitaxy
(MBE) on Si (100). Anneals at 1100°C for 20 sec in an Ar ambient improved
χmin, the ratio of backscattered 1.8 MeV He4 ions
in the aligned to random direction, from as-grown values of .07 to .26, to
post post-anneal values of .03 to .045. This is the best χmin yet reported
for the CaF2:Si system. The post-annealed films also show
improved resistance to chemical etching and mechanical stress, and increased
dielectric breakdown voltages.
Transient Processing of Titanium Silicides in a Non-Isothermal
Reactor
Authors: Wei C.S. , Van Der Spiegel J. , Santiago J. , Seiberling L.E. 
Published: March 2011

ABSTRACTTransient processing of titanium silicides on single-crystal Si in a
non-isothermal reactor provides high quality films. Heat from quartz-hal?gen
tungsten lamps and a small temperature gradient act as driving forces for
the reaction. The temperature gradient, small compared to the concentration
gradient, shows negligible influence on the formation process. The influence
of sample reflectivity on the other hand is appreciable. From Xe+ marker
experiments, Si atoms are found to be the moving species either up or down
the temperature gradient. Small amount of TiSi as an intermediate phase is
found to be coexistent with TiSi2. The silicide formation of the implanted
wafers is somewhat slower than that of the unimplanted wafers.
Incoherent Light Annealing of Selectively Implanted GaAs for
Mesfet Applications
Authors: Kitching S.A. , Badawi M.H. , Bland S.W. , Mun J. 
Published: March 2011

ABSTRACTCapped and capless incoherent light annealing of high and low dose silicon
implants into GaAs have been compared with conventional capless furnace
annealing of the same implants. The yield and uniformity of DC
characteristics of selectively implanted depletion mode MESFET's fabricated
on 2-inch wafers annealed by the above three methods have also been
compared. Capped incoherent light annealing was found to give results
comparable to and in some cases better than conventional furnace annealing
both in terms of activation of the implants and also device performance.
Rapid Thermal Annealing of Deposited Sio2 Films
Authors: Wong J. , Lu T.-M. , Cohen S.S. , Mehta S. 
Published: March 2011

ABSTRACTSilicon dioxide films have beep deposited at an oxygen pressure and
substrate temperature as low as 10−2 Pa and 300°C, respectively,
using a partially ionized nozzle-beam technique. The refractive index of the
film is equal to that of the thermally grown silicon dioxide film, but a
frequency shift was obsrved in the infrared absorption peak at 1045 cm as
compared to 1080 cm−1 of the thermally grown silicon dioxide
film. This frequency shift disappeared after the deposited film was annealed
in a rapid thermal annealing system utilizing an incoherent light source. We
emphasize that from the standpoint of device fabrication, although the
annealing temperature is high (%1100°C), the time is very short (seconds),
so that this process is still compatible to the requirementsof low
temperature processing. Effects of rapid thermal annealing on LPCVD and
PECVD oxides are also studied and the results are compared to that of the
oxide deposited by the partially ionized nozzle-beam technique.
Channeling Effect in Boron and Boron Molecular
Ion-Implantation
Authors: Delfino N. , Paine B.M. 
Published: March 2011

ABSTRACTThe extent of boron channeled into interstitial and substitutional sites is
measured for singly charged ions of B, BF, BCl, and BF2 implanted
into <100> silicon. We find that the most deeply penetrating boron
atoms ome to rest in interstiitial sites with the consequence that
electrical junctions are always more shallow than etallurgical junctions.
This result is essentially independent of ion mass, energy, and fluence.
Recent Advances in Si And Ge Zone-Melting Recrystallization
Authors: Chen C. K. , Gels M. W. , Choi H. K. , Tsaur B-Y. , Fan John C. C. 
Published: March 2011

ABSTRACTBy improving the thermal uniformity and stability of our graphite-strip-heater oven, we have been able to significantly improve the overall quality of ZMR Si films. We have observed unbranched subboundaries and new types of defects that are less extended than the usual sub-boundaries. The overall wafer flatness has been improved so that total warp is less than 4 μm for 3-inch wafers. We have also utilized the ZMR technique for producing thin Ge-on-insulator films.
Modifying Crystallographic Orientations of Polycrystalline Si Films Using Ion Channeling
Authors: Kung K. T-Y. , Ivepson R. B. , Reif R. 
Published: March 2011

ABSTRACTPolycrystalline silicon films 4800 Å thick deposited via low pressure chemical vapor deposition on oxidized silicon wafers have been amorphized by silicon ion implantation and subsequently recrystallized at 700°C. Due to channeling of the ions through grains whose <110> axes were sufficiently parallel to the beam, these grains survived the implantation step and acted as seed crystals for the solid-phase epitaxial regrowth of the film. This work suggests the feasibility of combining ion implantation and furnace annealing to generate large-grain, uniformly oriented polycrystal1ine films on amorphous substrates. It is a potential low-temperature silicon-on-insulator technology.
Photoelectron Spectroscopy of Conduction-Electron Energy
Distributions in Laser-Excited Silicon
Authors: Long J.P. , Williams R.T. , Rife J.C. , Kabler M.N. 
Published: March 2011

ABSTRACTElectron energy distributions, extending from equilibrium surface states
through transiently populated conduction band states, have been observed in
laser excited silicon by means of transient photoelectron spectroscopy.
Atomically clean (111) wafers in UHV were excited by 90 nsec, 2.33 eV or 65
nsec, 4.66 eV pulses. Photoelectron spectra were obtained with the 4.66 eV
pulses. Photovoltage shifts have been measured and found to saturate. We
have identified a feature in the excited state portion of the spectra due to
electrons which have equilibrated in the conduction band minima (CBM).
Electron temperatures as a function of 2.33 eV pump fluence have been
extracted from the spectra and are shown to be in equilibrium with the
lattice above 1100 K. Very hot non-equilibrium electrons are also observed
to ~ 4 eV above the CBM. A method of determining the diffusion depth of CBM
electrons has been developed and applied to our data.
Diffusion Mechanisms and Nonequilibrium Defects in SI
Authors: Mathiot D. , Pfister J. C. 
Published: March 2011

ABSTRACTThe problem of the respective contributions of vacancies and self interstitials to diffusion mechanims in silicon is clarified by using a consistent model for the diffuion of P, As and B which involves the resolution of the coupled continuity equations for the impurities, the vacancies and the self-interstitials. This model allows also the understanding of basic features concerning the kinetics of the point defects in presence of impurities.
Transient Enhanced Diffusion and Gettering of Dopants in Ion Implanted Silicon
Authors: Pennycook S. J. , Narayan J. , Culbertson R. J. 
Published: March 2011

ABSTRACTWe have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. We show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase-epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. We discuss the conditions under which the various effects may or may not be observed, and discuss preliminary observations on As+ implanted Si.
Defect Formation and Hydrogen Trapping in H+ Implanted FZ Silicon
Authors: Choyke W. J. , Spitznagel J. A. , Doyle N. J. , Wood S. , Irwin R. B. 
Published: March 2011

ABSTRACTThe formation and annealing of buried damage layers in hydrogen implanted N-type float zone <111> silicon has been studied by Rutherford Backscattering/ion channeling and cross-section transmission electron microscopy. Implantation with 50 keV or 75 keV H+ ions was conducted at temperatures of 95K, 300K and 800K at fluences of 2×1017 H+/cm2, 8×1017 H+/cm2 and 1×1018 H+/cm2. Post implantation annealing was conducted at temperatures up to 800K. The results show a temperature dependent transition from a highly hydrogen doped amorphous zone bounded by strongly diffracting (TEM) 2–5 nm diameter defects for implantation at 95K to a crystalline microstructure containing small dislocation loops and ∼40% of the implanted hydrogen for implantation at 300K. Defect production and annealing and hydrogen trapping in the damage zone are shown to depend on the relative implantation and post implantation annealing temperatures.
The Chemistry of Oxygen in Silicon
Authors: Mikkelsen J. C. 
Published: March 2011

ABSTRACTSome of the key issues involving the chemistry of oxygen in silicon crystals are presented in this paper. The incorporation of oxygen into Czochralski-grown ingots from melt contact with silica crucibles is described in the context of the Si-SiO2 phase diagram. The techniques for characterizing oxygen in silicon are reviewed, with an emphasis on the use of secondary ion mass spectrometry (SIMS) and 18O isotope substitution. The intrinsic diffusivity and solubility of oxygen in silicon derived from these SIMS measurements are compared to similar results from other techniques as well as related extrinsic behavior of oxygen. Aggregation phenomena involving oxygen, including thermal donor formation and precipitation are discussed. Finally, the recent progress in understanding internal gettering and shear stress are summarized.
A Model That Describes the Role of Oxygen, Carbon, and Silicon Interstitials in Silicon Wafers During Device Processing
Authors: Hartzell R. A. , Schaake H. F. , Massey R. G. 
Published: March 2011

ABSTRACTA model has been developed that simulates oxygen precipitation in silicon wafers during high temperature device processing. The approach used to calculate the nucleation and growth of oxygen precipitates is radically different from other approaches presented in the literature. A discrete rate equation representation of nucleation and growth has been transformed into a continuum representation in the form of a partial differential equation. This partial differential equation describing both the statistical clustering of oxygen during nucleation and the diffusion driven transport during precipitate growth is solved continuously starting from crystal growth through any arbitrary time-dependent temperature process.
Oxygen Precipitation in CMOS Wafers
Authors: Forbes L. , Whitwer F. D. , Peng J. D. 
Published: March 2011

ABSTRACTThe application of denuding, nucleation, and intrinsic gettering in CMOS integrated circuit processes is described. Specifically, it will be demonstrated that an initial oxidizing step, as many manufacturers are using, seriously retards the effectiveness of any subsequent nucleation step or procedure. The results of a large number of one-step, two-step, and three-step heat treatments are summarized and design criteria for controlled oxygen precipitation in integrated circuit fabrication are described. Two-step heat treatments, without denuding and with the nucleation step first, have been used to induce precipitates close to the surface of CMOS wafers and DLTS measurements made to deduce the effectiveness of intrinsic gettering and the electrical characteristics of precipitation induced microdefects.
Rapid Diffusion of Molybdenum Trace Contamination in Silicon
Authors: Tobin S. P. , Greenwald A. C. , Wolfson R. G. , Meier D. L. , Drevinsky P. J. 
Published: March 2011

ABSTRACTMolybdenum contamination has been detected in silicon epitaxial layers and substrate wafers after processing in any one of several epitaxial silicon reactors. Greatly reduced minority carrier diffusion lengths and lifetimes are consistent with Mo concentrations measured by DLTS in the 1012 and 1013 cm−3 ranges. Depth profiling of diffusion length and the Mo deep level show much greater penetration than expected from previous reports of Mo as a slow diffuser. The data indicate a lower limit of 10−8 cm2/sec for the diffusion coefficient of Mo in silicon at 1200°C, consistent with high diffusivities measured for other transition metals.
Diffusion of Dopants in (111) Silicon During High Temperature Heat Treatment in Nitrogen
Authors: Kook T. , Jaccodine R. J. 
Published: March 2011

ABSTRACTThe diffusion of various dopants( B, P, As, and Sb) in (111) silicon during high temperature( 1100°C ) heat treatment in nitrogen depends on the capping layers, i.e., SiO2, Si3 N4, and SiO2 + Si3 N4, layers. The junction motion of all dopants were retar ed in the bare silicon compared with that in the SiO2 + Si3 N4 capped silicon. The apparently retarded junction motion of As and sb diffused specimens in the bare silicon is due to the severe out-diffusion loss of dopant atoms and As and Sb diffusion are in fact enhanced during thermal nitridation of silicon in N2.
Ion Implantation Disorder in Strained-Layer Superlattices
Authors: Arnold G. W. , Picraux S. T. , Peercy P. S. , Myers D. R. , Biefeld R. M. , Dawson L. R. 
Published: March 2011

AbstractCantilever-beam bending and RBS channeling measurements have been used to examine implantation-induced disorder and stress buildup in In0.2Ga0.8As/GaAs SLS structures. Implantation fluences from 1011 to 1015/cm2 were used for 150 keV Si, 320 keV Kr, and 250 keV Zn in SLS and GaAs bulk materials. The critical fluence for saturation of compressive stress occurs prior to amorphous layer formation and is followed by stress relief. For all the ions the maximum ion induced stress scales with energy density into atomic processes and stress relief occurs above ∼1 × 1020: keV/cm3. Stress relief is more pronounced for the SLSs than for bulk GaAs. We suggest that stress-relief may lead to slip or other forms of inelastic material flow in SLSs, which would be undesirable for active regions in device applications. Such material flow may be avoided by limiting maximum fluences or by multiplestep implantation and annealing cycles (or hot implants) at high fluences.
Compound Semiconductor Surfaces and Interfaces: Whence Fermi Level Pinning?
Authors: Woodall Jerry M. 
Published: March 2011

AbstractExcept for a few special cases, the electrical and optical properties of most III-V semiconductor surfaces and interfaces can be explained in terms of surface Fermi level pinning. However, despite years of research there is no universal agreement on the origin of this pinning. This problem is of more than just academic interest since pinning affects optoelectronic device performance via surface recombination losses, and high speed device performance through uncontrollable ohmic and Schottky contact properties for MESFETs and through a high interface trap density for MISFETs.This talk reviews some of the approaches to the pinning problem and presents some recent results on the role of misfit dislocations in pinning. In particular it will be shown that there are are several models which can explain the usually observed pinning positions. However, we have developed a modified work function model capable of explaining both the usual pinning positions and the experimentally observed exceptions in Schottky barrier height for some metal/semiconductor interfaces. The electrical properties of lattice mismatched GaInAs/GaAs heterojunctions suggest that Fermi level pinning occurs at misfit dislocations.
Electron - Beam Measurements of Epitaxial GaAs Layers
Authors: Paz O. , Borrego J. M. 
Published: March 2011

AbstractIn studying the growth of epitaxial layers in III-V compounds, it is advantageous to obtain information on the early stage of the growth that takes place at the substrate-epitaxial layer interface. In this paper, we describe a method of measuring the recombination velocity at this interface, as well as the minority carrier diffusion length in the bulk of the epitaxial layer. A bi-directional diffusion of excess carriers was modeled, with layer thickness, diffusion length and recombination velocity as variables. Layer thickness was determined using spreading resistance, the other two variables can be separated by measuring layers of several thicknesses. Some carriers diffuse from the point of generation toward the surface and are collected at a Schottky barrier depletion layer, The remaining carriers diffuse from the point of generation toward the epi-substrate interface where they recombine.
A Comparison of Transient Annealing Methods for Silicide Formation
Authors: Harper R. E. , Sofield C. J. , Wilson I. H. , Stephens K. G. 
Published: March 2011

AbstractNickel and cobalt silicides have been formed by raster-scanned electron beam and flash-lamp irradiation of thin metal films on single crystal (100) and (111) silicon wafers. RBS and channelling measurements indicate that the NiSi2 is epitaxial and of good crystalline quality (Xmin 4% on (111)); epitaxial CoSi2 was more difficult to form and of somewhat poorer quality. The elastic recoil technique has been used to determine bulk and interfacial light element contamination. These measurements have been correlated with resistivity and SEM studies of the surface textures.
Cross-Sectional Tem Study of Rhodium on Single Crystal and Amorphous Silicon
Authors: Herd S. R. , Psaras P. A. , Fishera I. J. , Tu K. N. 
Published: March 2011

AbstractA crystalline interfacial bilayer, consisting of about 5nm each of RhSi and Rh2Si was found after E-beam deposition of 95nm of Rh onto either Si[100] or α-Si substrates. Cross sectional TEM of the as-deposited and annealed specimens showed no change occurred after 24hrs at 200° C. With infinite supply of Si, as on the Si[100] substrate, RhSi was found as a major growing phase, although Rh2Si also grew at a much slower rate. With a limited supply of Si, as in the α-Si case, RhSi first formed until all α-Si was consumed (2 hrs at 400°C) and then transformed partially to Rh2Si after 4 hrs at 400°C. This transformation could be confirmed by RBS since Rh2Si layer thickness exceeded 30nm
Structural Unit Models for High Angle Symmetrical Tilt Boundaries in Ordered Compounds with the Ll2 Structure
Authors: Farkas D. 
Published: March 2011

ABSTRACTHard sphere models were used to determine densest configurations in symmetrical [100] and [110] tilt boundaries in compounds with the Ll2 structure. The minimum allowed interatomic distances used in these models were estimated from interatomic potentials and the structures of the intermetallic phases in the binary system. The structural unit model is used to analyze the possible ground states for ordering.Two different cases were analyzed corresponding to compounds with “soft” potentials (i.e. Cu3 Au) and “hard” potentials (i.e. Ni3Al). For the Cu3Au type the grain boundary structures obtained were similar to those reported by other investigators for pure fcc metals. Several boundaries were found to be a “two phase” structure, differing in composition and ordering state. This leads to a certain degree of clustering in the boundaries. The contribution of clustering to the grain boundary energy is calculated in a point approximation based on the first coordination shell.For compounds of the Ni3Al type the structures that are densest were found to be generally diffetent from the low energy configurations of boundaries in, pure fcc metals and Cu3 Au. These configurations preserve order, but are much less dense. The possibility of grain boundary “phases” that are not present in other fcc materials may constitute an explanation for the extreme GB weakness observed in Ni3Al and other Ll2 compounds with high ordering energy.
Dislocation Core Structure and the Anomalous Yield Behavior of Li2Ordered Alloys At Elevated Temperatures
Authors: Vitek V. , Pope D. P. 
Published: March 2011

ABSTRACTIn many LI2ordered alloys the flow stress increases with increasing temperature and is in this “anomalous” regime strongly dependent on orientation and sense of the applied stress. These dependences can be predicted from the nature of the dissociation and core structure of the 1/2<101> screw superpartials in these alloys. Computer modelling shows that two different configurations, a glissile one on {lll} planes and a sessile one on {010} planes, exist and both are described here in detail. The anomalous increase of the flow stress may then be explained by an increasing amount of core transformations from the glissile to sessile forms as the temperature increases. The theoretical model for the immobilization of screw dislocations by this mechanism is then discussed and its validity illustrated by comparison with experimental results on Ni3(Al, Ta) single crystals.
High Temperature Ductility Minimum in Rapidly Solidified Ni3Al - B
Authors: Taub A. I. , Huang S. C. , Chang K. M. 
Published: March 2011

ABSTRACTThe elevated temperature mechanical properties of rapidly solidified, boron doped Ni3Al have been investigated. Melt spun ribbon, plasma deposits and HIP'ped powder were tested with the same general results. It was found that the boron doped, rapidly solidified alloy exhibits an increasing flow stress with increasing temperature similar to that reported for conventionally cast Ni3Al. In addition, the rapidly solidified alloys exhibited a severe ductility minimum in the range 500–750C. The ductility minimum is relatively insensitive to both boron and aluminum concentration, but the embrittlement onset temperature changes with processing and testing parameters. In all cases, the onset of the ductility drop coincides with the onset of the decrease of the flow stress. It is postulated that this behavior is due to a change in the flow mechanism at elevated temperature to one that is associated with grain boundary stress concentration.