bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Characterization of Intentional Dopants in HgCdTe using Sims, Hall-Effect, and C-V Measurements
Authors: Lapides L. E. , Whitney R. L. , Crosson C. A. 
Published: March 2011

ABSTRACTThe properties of selected dopants in liquid-phase epitaxial (LPE) layers of HgCdTe have been studied using secondary ion mass spectrometry (SIMS), Hall-effect, and capacitance-voltage (C-V) measurements. The layers were grown from Hg-rich melts on {111}-oriented CdTe and CdZnTe single-crystal substrates. Diodes, for the C-V measurements, were homojunctions formed by ion implantation or heterojunctions formed by the growth of a second layer on the base layer. Dopant concentration distributions in both single- and double-layer structures were characterized by SIMS and C-V measurements. The dopant profiles measured by SIMS were quantified using relative sensitivity factors calculated from ion implanted impurity profiles measured on standard reference samples. Using specialized SIMS techniques, such as molecular ion spectrometry, As concentrations as low as 2 × 1015 cm−3 have been measured. In the HgCdTe:In/HgCdTe:As system minimal dopant interdiffusion is observed in SIMS profiles. The growth of the second layer has insignificant effect on the As distribution in the base layer, and C-V data indicate that the electrical properties change only slightly. Carrier types and concentrations were determined by Hall effect and C-V measurements. Good agreement between dopant concentrations and carrier concentrations was observed, indicating 100% activation of the dopant atoms, for all dopants studied. Examples of implant calibration profiles, dopant concentration distributions, carrier concentration vs temperature measurements, and 1/C2 vs V data are presented, along with graphs and tables comparing dopant profiles with electrical properties.
Hydrogen Measurement of Thin Film Silicon: Hydrogen Alloy Films Technique Comparison
Authors: Pollock Gary A. 
Published: March 2011

ABSTRACTThe hydrogen content in thin film silicon:hydrogen alloy material has been measured by five techniques: 15N nuclear resonance reaction analysis, secondary ion mass spectrometry, infrared spectroscopy, nuclear elastic scattering spectroscopy, and Rutherford backscattering spectroscopy. NRA and SIMS data agree most closely in this study, although SIMS data from three of four laboratories are considerably scattered. The hydrogen content of TFS ranges from 18% at a deposition temperature of 150°C to 10% at 250°C. It varies little, if any, with thickness. Some advantages and disadvantages of the five techniques are discussed.
MeV Helium Microbeam Analysis: Applications to Semiconductor Structures
Authors: Brown R. A. , McCallum J. C. , McKenzie C. D. , Williams J. S. 
Published: March 2011

ABSTRACTWe have employed an MeV He+ microbeam for the analysis of micron-scale semiconductor structures. The analysis combines a unique beam scanning and mapping capability with powerful ion beam techniques such as particleinduced x-ray emission, Rutherford backscattering and ion channeling. These analysis capabilities are applied to the measurement of dopant profiles in polycrystalline resistors, identification of micro-alloying in metal-GaAs contacts and damage/atom location in individual polycrystalline silicon grains. The latter application utilises the newly-developed technique of channeling contrast microscopy.
Elastic Recoil Analysis of Hydrogen in Ion-Implanted Magnetic Bubble Garnets Using 44 MeV Chlorine Ions
Authors: Leiberich A. , Flaugher B. , Wolfe R. 
Published: March 2011

ABSTRACTElastic recoil analysis using 44 MeV chlorine ions is a precise and timesaving method of measuring hydrogen profiles of ion implanted magnetic bubble garnets. Neon, nitrogen and hydrogen ion-implanted modified yttrium iron garnets, which are used for magnetic bubble devices based on ion implanted propagation patterns, (12P2), were studied with respect to their hydrogen concentration-depth distributions. A description and calibration of the elestic recoil analysis setup are presented along with the necessary simple algorithms to obtain the final hydrogen concentration-depth profiles from the measured energy spectra generated by recoiled protons. The garnet samples were annealed with or without a surface coating of SiO2. At 250°C, the hydrogen was found to diffuse throughout the aamaged surface layer but not into the underlying undamaged material. At 350°C, the hydrogen diffused out of the uncoated garnet, but was sealed into the implant damaged garnet layer by the thin oxide coating. Such hydrogen retention correlates with previously reported beneficial effects of an oxide layer deposited at a low temperature after implantation but before processing on ion implanted bubble devices.
Surface Composition of Carburized Tungsten Trioxide and its Catalytic Activity
Authors: Nakazawa Masatoshi , Okamoto H. 
Published: March 2011

AbtractThe surface composition and electronic structure of carburized tungsten trioxide are investigated using X-ray photoelectron spectroscopy (XPS). The relationship between the surface composition and the catdlytic activity for methanol electro-oxidation is clarified. The tungsten carbide concentration in the surface layer increases with the carburization time. The formation of tungsten carbide enhances the catalytic activity. On the other hand, the presence of free carbon or tungsten trioxide in the surface layer reduces the activity remarkably. It is also shown that, the higher the electronic density of states near the Fermi level, the higher the catalytic activity.
Instantaneous Impedance of Aluminium in Anodic Polarization Status
Authors: Yingyang Zhu , Kuang Wang , Rizhang Zhu , Wenqi Zhang 
Published: March 2011

ABSTRACTThe instantaneous impedance of AL in 1N NaCl at various polarization tines has been measured using LapLace transformation method. In an instant of beginning polarization, the dependance of interfacial resistance, Rf, on polarization current, ip, follows:Interfacial capacitance, Cf, however, indepenrs of ip, only depends on film's thickness. In the course of polarization, Rf changed hardly with time, Cfchanged greatly. This is due to little difference between the resistance on corroded region and the resistance on the region with film, and great difference capacitance on both regions. A reasonable model has beon pronosed to explain the experimental results.
Characterization of Precipitates Decorating Stacking Faults in Single Crystal Silicon
Authors: Ryoo K. , Drosd R. , Wood W. E. 
Published: March 2011

ABSTRACTOxidation of silicon wafers containing lattice damage at the surface normally results in the formation of extrinsic stacking faults. Optical microscope investigation following decorative etching shows that on certain samples the faults have a straight line appearance while on others the ends of the defect are much enlarged giving a “dog-bone” shape. TEM investigation confirmed that the dog-bone shaped faults were decorated with colonies of precipitates near their edges. These colonies resided on the (111) fault planes and extended over several thousand angstroms. Precipitate spots were not found in the diffraction pattern due to the small volume fraction, but translational Moire fringes were observed for certain matrix g-vectors, thus aiding in the crystallographic analysis. EDX analysis was also performed and revealed that precipitates were due to Cu and Ni contamination. The electrical impact of the defects on P-N junction was measured, showing a strong influence on both reverse and forward bias current/ voltage characteristics.
An In-Situ Study of Velocity/Driving Force Relations for Interfacial Migration
Authors: park Woonsup , Allen Samuel M. 
Published: March 2011

ABSTRACTThe migration kinetics of antiphase boundaries (APBs) in long-range ordered Fe-Al alloys are analyzed using in-situ hot-stage transmission electron microscopy, making it possible to observe the interfacial migration directly as it occurs. The observed domain structures are essentially two dimensional due to the thin foil configuration of the specimen, facilitating analytical interpretation of the data. By measuring the local curvatures and migration distances from a series of micrographs taken at a constant temperature, the proportionality constant relating velocity to curvature can be determined. This proportionality constant, called the mobility for APB migration, is found to be independent of the curvature for <100> APBs in Fe-27 atomic percent Al at 745K, having the value of 4.8×10−19 m2/s.
Electron Microscopy Study of Structural Changes During Isothermal Annealing of a Ni4Mo-Based Alloy Containing Chromium
Authors: Vasudevan K. , Stansbury E. E. 
Published: March 2011

ABSTRACTTransmission electron microscopy has been used to study phase transformations in a Ni4Mo alloy containing 2.08 wt pct chromium following isothermal annealing at 850, 800 and 700°C. At these temperatgres, the DO22 phase forms initially, which then transforms to Ni3Mo. At 700°C, the DO22 phase forms from bands composed of Ni4Mo and Ni2Mo aligned parallel to {111} fcc planes, and is relatively stable. A second mechanism for the formation of Ni3Mo occurs at 700°C. Large Ni4Mo domains form at grain boundaries. These su~sequently transform to Ni3Mo, with the simultaneous presence of stacking faults on (010) Ni3Mo planes.These observations are correlated to the optical microstructure. Grain size influences the type, volume, and distribution of second phases. Sequences and mechanisms of transformations are related to the experimental observations.
Detection and Imaging of Supported Catalyst Particles
Authors: Treacy Michael M. J. 
Published: March 2011

ABSTRACTIn this short review we contrast and compare the relative merits of three imaging techniques in the CTEM and STEM, for detecting subnanometer size catalyst clusters. It is shown that incoherent dark field signals, such as those obtained by hollow-cone illumination in the CTEM, and the annular detector in the STEM, are significantly more sensitive to subnanometer size clusters than the bright field signal. Sensitivity to clusters of high atomic number increases as the illumination (or detector) semi-angle increases, although at the expense of decreased signal-to-noise. The STEM annular detector signal offers advantages over the CTEM hollow-cone signal in this respect since it has a higher electron collection efficiency. A further advantage of the STEM is that image contrasts may be enhanced by electronically combining the annular detector signal with the axial energy loss signal. This ratio method, or Z contrast technique, has been used with success to detect single Pt atoms on thin low atomic number supports.
Characterization of Reactively Sputtered Titanium Carbide Films by Analytical Electron Microscopy
Authors: Tafto J. , Rajeswaran G. , Saulys T. 
Published: March 2011

ABSTRACTTICx films prepared by reactive sputtering using a Ti target and different methane partial pressures were characterized by analytical transmission electron microscopy. The films are polycrystalline, and the plasmon energy increases considerably with increasing carbon content. Combination of the information obtained from electron energy loss plasmon and core loss spectra, and electron diffraction indicates that x in TiCx increases linearly with methane partial pressure. We find that the face centered cubic TIC phase spans the composition from TiC0.2 to TiC1.0 and when x<l we have a mixture of TiC1.0 and amorphous C.
Origin of Grown-in Dislocations in III-V Compound Semiconductor Epitaxial Layers
Authors: Nakahara S. , Chu S. N. G. 
Published: March 2011

ABSTRACTA transmission electron microscope was used to study the origin of grown-in dislocations observed in quaternary InGaAsP layers grown by vapor phase epitaxy on (001) InP substrates. Many of the grown-in dislocations were found to exist as dislocation dipoles and were connected to particles formed at the lnGaAsP/lnP interface. X-ray micro-analysis has indicated that the particles are quaternary alloys having chemical compositions slightly richer in both Ga and P than that of the lattice-matched InGaAsP layer. In some cases, this compositional deviation led to a significant lattice mismatch. As the particle grows larger, a strain relaxation occurs by generating misfit dislocations around the particle in the form of a dislocation half loop. If these dislocation half loops do not develop into a complete loop by totally surrounding the particle, they leave two unclosed dislocation segments (a dislocation dipole), which are replicated by the quaternary overlayer along the substrate normal direction, i.e., [001]. These dislocations eventually become a source for grown-in dislocations.
TEM Studies of Low Energy Argon and Iodine Ion Milling Phenomena in Compound Semiconductors
Authors: Cullis A. G. , Chew N. G. , Hutchison J. L. 
Published: March 2011

ABSTRACTThe nature of disorder produced by low energy Ar+ and I+ ions (and atoms) in the III–V compound semiconductors InP and InSb, and in the II–VI semiconductors CdTe, ZnS and ZnSe has been studied in detail by conventional and high resolution transmission electron microscopy. It is demonstrated that for Ar+ ion bombardment the disorder in the III–V compounds comprises segregated indium islands which accumulate on the machined surfaces, while for the II–VI compounds the disorder consists of dense arrays (∼1011 cm−2) of small dislocation loops near to each bombarded surface. When Ar+ ions or Ar atoms are used for thin specimen preparation by milling prior to electron microscopy, the disorder produced gives contrast which seriously obscures images and so complicates their interpretation. This problem concerning the presence of artifactual defects can be greatly reduced or even eliminated by the use of reactive I+ ion milling for the final thinning of specimens.
The Growth of Interdisciplinary Materials Research at Suny-Buffalo
Authors: Anderson Wayne A. 
Published: March 2011

ABSTRACTMaterials Science and Materials Engineering are recognized as essential areas of growth for advancement in applications of new devices and materials. The educational program at the university level must be dynamic in nature to keep pace with advances in science and instrumentation. State University of New York at Buffalo has sponsored an interdisciplinary proposal solicitation to promote efforts in the forefront of science. Materials-related efforts are described herein which will lead to improved external funding of research, improved educational programs, more sophisticated instrumentation, high quality graduate students, and high quality faculty.
Plasma Emission Spectroscopy and Chemical Analysis of Amorphous Hydrogenated Carbon
Authors: Park Chang Soo , Bodart Jeffrey R. , Han He-Xiang , Feldman Bernard J. 
Published: March 2011

AbstractThe emission spectra of various hydrocarbon plasmas used in the growth of amorphous hydrogenated carbon (α-C:H) thin films have been measured.The presence of CH, H, H2, and C2 species in the plasma have been observed.The chemical composition of the α-C:H films was determined by combustion analysis and shows roughly equal atomic concentrations of H and C and a surprising large concentration of 0.The plasma emission spectra and chemical composition results can be partially understood in terms of relative bond strengths of the different molecules involved, and these results give some insights into the growth kinetics of α-C:H thin films.
Reactive Ion Etchtng Model for Silicon Dioxide Guadalupe Fortuno
Authors: Fortuño Guadalupe 
Published: March 2011

AbstractThe etching of SiO2 was studied during reactive ion etcing (RIE) in an SF plasma.The etch rate of SiO2, the sheath voltage and the wafer temperature were measured as a function of the percentage of SF6 in Ar and as a function of the total pressure.This was done with the purpose of better understanding the etching mechanisms involved.The results are compared with similar experiments carried out with CF4 and Ar [1].Tests to the model formulated will also be given.
Plasma Etching of Si in SF6/O2 and NF3/O2 Mixtures: Computer Simulations And Experimental Results.
Authors: Anderson Harold M. , Smith Bradley K. , Light Ron W. 
Published: March 2011

AbstractProfile control in polysilicon etching with SF6/O2 and NF3/O2 gas mixtures has been explored as a function of feed gas composition, power, pressure and total flow.Polysilicon appears to etch anisotropically under certain anomalous combinations of these parameters, such as high power/dilute etchant gas composition, low power/high etchant gas composition and high power/high etchant gas composition.Very rapid etch rates (3.5 μm/min) and anisotropic etching were obtained simultaneously in SF6/O2 mixtures at 250 mtorr.In order to provide a rational for explaining these anomalies, a kinetic model for these plasmas has been developed which couples electron impact events in the plasma to gas-phase chemistry and surface reactions of the etching process.Peculiarities in the electron energy distribution function (EEDF) of these gas mixtures, determined by Boltzmann calculations, appear related to the anisotropy under dilute conditions.However, anisotropic etching observed at 250 mtorr and rich SF6 gas mixtures appears more related to anomalies in power deposition to the discharge, possibly including wave interactions or resonant processes.Comparisons between computer simulations and experimental results are presented.
Considerations in Plasma Pattern Transfer Process Development
Authors: Herb G. K. 
Published: March 2011

AbstractPattern transfer by plasma etch has become an indispensable tool to fabricate semiconductor devices whose critical feature dimensions are less than 3.0 μm.Traditional wet chemistry techniques do not maintain linewidth fidelity (isotropic profile) and lose applicability for features whose aspect ratio (width:thickness) is below 3:1.Plasma processes must keep pace with the rapid introduction of innovative device designs whose packing density is continually increasing.Hence many etch process developments are based on empirical, rather than theoretical, wisdom.Often the desired etch results of anisotropy, selectivity, uniformity and cleanliness become competing requirements.Many of today's circuit designs have structures, topography and feature dimensions so interrelated that difficulty is usually encountered during the etch process development.Many of the single layer materials that were used in yesterday's devices have become multiple material films in the current advanced designs, increasing the complexity of the etch process and confusing the interpretation of the process results.An increasingly important tool that can be used for successful etch development is the statistical fractional factorial experimental design.This paper will discuss a few examples of plasma process development that involve a rank ordering of the importance of competing etch results.
Plasma Processing in Semiconductor Manufacturing
Authors: Tracy Clarence J. 
Published: March 2011

AbstractThe implementation of plasma deposition and reactive ion etching into a semiconductor VLSI manufacturing process is rarely trivial.In some cases isolated process modules may appear to function well until integrated into a lengthy product flow, where interactions occur with prior or subsequent processing steps.In addition, dry processes have some unique and sometimes undesirable characteristics which need to be considered.Examples of both of these kinds of problems will be shown.Opportunities still exist for research to lead to a better understanding of mechanisms and for development work to improve the equipment and specific processes.
Anisotropic Dry Etching of S1O2 on Si and its Impact on Surface and Near-Surface Properties of the Substrate.
Authors: Oehrlein G. S. , Coyle G. J. , Tsang J. C. , Tromp R. M. , Clabes J. G. , Lee Y. H. 
Published: March 2011

AbstractIn the present paper structural and chemical changes which can occur in the surface and near-surface properties of the substrate during anisotropic dry etching of SiO2 on Si will be reviewed.Silicon specimens which had been etched in CF4/X%H2 (X≤40) have been characterized by X-ray photoelectron emission spectroscopy, He ion channeling, H profiling and Raman scattering techniques.Key results of our studies are summarized as follows: Plasma exposure of a Si surface leads to the deposition of a thin (≤50Å thick) C,F-film.A Si-carbide containing Si region is formed during RIE which is localized near the fluorocarbon-film/Si interface.The near-surface region (∼30–50Å) of the Si substrate is also heavily disordered as found by ion channeling and Raman scattering.A modified, less damaged Si region has been found in the case of hydrogen-based etching gases, which extends from about 30–50Å from the surface to a depth in extent of 250Å and contains a high concentration (∼ 5 at.%) of H as shown by hydrogen profiling techniques.From the observation of Si-H and Si-H2 vibrational modes by Raman scattering it has been shown that some of the H is bonded to the Si lattice.
Reactive Ion Etching Damage to Shallow Junctions
Authors: Wu I. W. , Bruce R. H. , Mikkelsen J. C. , Street R. A. , Huang T. Y. , Braun D. 
Published: March 2011

AbstractThe damage of reactive ion etching to shallow junctions is an important consideration in advanced technology.In this paper, the damage incurred during contact etch is studied, with emphasis on those defects responsible for junction leakage of shallow junctions.Shallow p+/n and n+/p junctions have been prepared with depths of 160 nm.Junction leakage measurements have been made for various amounts of silicon loss up to within 20 nm of the junctions by using a CHF3 + CO2 plasma.The degree of chemical and structural damage has been characterized by using photoluminescence, SIMS, and spreading carrier profiling.The leakage current density was found to depend strongly on contact area and increase rapidly with junction etch depth after the etched surface has extended to within 80 nm of the junction boundary.The concentration and depth of damage increases with increasing plasma exposure until saturation.Etching induced defects are observed in photoluminescence, and one such defect is identified as a carbon interstitialcy.Enhanced diffusion effects were observed for both chemical contamination from the etch gas and the junction dopants.The spatial distribution of the chemical and structural damage has been found to correlate with the junction leakages.The annealing behavior of damage has also been investigated.
Modification of the Electrical Properties of a GaAs Surface by Plasma Exposure
Authors: Oren Moshe , Zemon; Stanley 
Published: March 2011

AbstractPlasma processing is an essential part for the fabrication of GaAs ICs.It was found that the exposure of sulfur doped n-type GaAs layers to a plasma of helium, oxygen, or nitrogen changed their electrical characteristics without introducing crystalline damage, as observed by electron diffraction measurments or etching.Exposure to a plasma depletes the surface carrier concentration but the mobility remains unchanged.Compared to O2 and N2 the helium plasma has the largest effect on the GaAs surface.Exposure of S-doped GaAs layers to a He plasma at 350°C produces two new deep levels at 840-nm and in the region between 863 and 872-nm.These levels were not observed for a He plasma exposure at room temperature or for O2 plasma exposure at 350°C.