bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ebic Study of Fe Precipitation on Bulk Stacking Fault in Czochralski-Grown Silicon
Authors: Shen B. , Sekiguchi T. , Chen P. , Yang K. , Chen Z. Z. , Zheng Y. D. , Sumino K. 
Published: April 2011

ABSTRACTFe precipitation on bulk stacking faults in Czochralski-grown silicon are investigated by means of the electron-beam-induced-current (EBIC) technique and other techniques. It is found that Fe impurities only precipitate on Frank partial dislocations bounding stacking faults when the specimen is cooled slowly; however, they precipitate on both Frank partials and fault planes when the specimen is cooled fast. It is explained that small oxygen precipitates on fault planes, together with Frank partials, serve as the gettering centers for Fe impurities in the fast cooled specimen.
Room-Temperature Migration of Ion-Implanted Boron in Silicon
Authors: Collait E. J. H. , Weemers K. , Gravesteijn D. J. , van Berkum J. G. M. , Cowern N. E. B. 
Published: April 2011

ABSTRACTRoom temperature migration and clustering behaviour of implanted boron into silicon has been investigated by performing ion implantation of the 11B isotope into MBE-grown in-situ 10B-doped epitaxial Si-layers. We, for the first time, show that a fraction of the implanted boron migrates very deep into the bulk of the Si with substitutional 10B acting as trap centers for the migrating 11B.
Wet Oxidation of Poly-Si1-xGex Layer Grown on SiO2/Si
Authors: Han Ping , Wu Mang , Ma Junru , Huang XiaoDong , Chen Hao , Hu Liqun , Zheng Youdou 
Published: April 2011

ABSTRACTIn this paper, we report on the experiment results of wet oxidation of Si1-xGex on SiO2. AES and XPS measurements were performed to study the effect of the oxidation on the Si1-xGex layer. A possible mechanism was proposed.
Photoresist Stripping using Ozone/Deionized Water
Chemistry
Authors: Kashkoush I. , Matthews R. , Novak R. , Brause E. , Carrillo F. , Rajaram B. 
Published: April 2011

ABSTRACTThe use of sulfuric acid to strip photoresist from silicon wafers is a
widely employed technique in the semiconductor manufacturing community. In
most cases, the acid is combined with hydrogen peroxide to oxidize stripped
photoresist material, though the use of sparged ozone in sulfuric solution
is also used to remove resist residues on wafers following the ashing
process. Although they have been used for many years, sulfuric acid
processes also have proven to be costly. This is due to the need for
frequent bath change-outs and the use of high temperature which impose
safety and environmental concerns. As a result of these and other
considerations, the use of mixtures of ozone and de-ionized water for
photoresist stripping has been investigated. Results show that the technique
effectively removes hard-baked resist (ashed and un-ashed) from bare silicon
and patterned wafers and produces cleaner surfaces (i.e. particles and
metals), compared to outcomes from SPM processes.
Mirror-Polishing Residual Damage characterization in the
Subsurface of Si Wafers Using N2 Laser /mm-Wave Photoconductivity
Amplitude Technique
Authors: Ogita Y. , Hosoda Y. , Miyazaki M. 
Published: April 2011

ABSTRACTThe problem is occurring that gate oxide integrity (GOI) might be influenced
on the residual subsurface damages induced by mirror polishing. The
correlations between mirror polishing conditions, micro roughness, and
photoconductivity amplitude (PCA) signals are measured and discussed in a
small roughness region of micro roughness Rrms such as 0.095 nm
to 0.247 nm. The theoretical analysis shows that PCA signal is possible to
reflect a subsurface lifetime.The discussions lead to result that the GOL is
mainly dependent on subsurface damages in such small roughness region, PCA
signals measured with an UV/mm-wave noncontact technique correlate closely
with the GOI yield. It is concluded that the PCA technique makes it possible
to characterize subsurface damages and to estimate GOI yield.
Comparison of Removal Efficiency of Cu Impurity on Si(100)
Depending on the Cleaning Splits of (UV/O3 + HF) and
(H2O2 + HF)
Authors: Jeon Hyeongtag , Choi Baikil 
Published: April 2011

ABSTRACTSi surface cleaning has been studied intensively in these days. One of the
major concerns is about the removal of metallic impurities on Si surface. In
this study we choose contaminant element of Cu which shows high
electronegativity value compared to Si's. The Si substrate was cleaned with
using piranha (H2SO4:H2O2=4:1)
and HF (HF:H2O=1:100) solutions to eliminate the organic
impurities and native oxide. The initial Si substrate was then contaminated
intentionally by dipping into the 1 ppm standard solution of Cu and cleaned
by the cleaning splits of the chemical solution HF combined with
UV/O3 treatment and the chemical mixture of
H2O2 and HF. The initial substrates which were
contaminated with the standard Cu solution exhibited the contamination
levels of 1013–1015 atoms/cm2 and these
substrates were cleaned and showed Cu concentration down to the levels as
lower as 1010 atom/cm2 which were monitored by TXRF
(total reflection X-ray fluorescence). And repeated treatments of these
cleaning splits improved the surface microroughness of these initial
substrate which were measured by AFM (atomic force microscope). The surface
and interface morphologies contaminated with Cu were examined by SEM
(scanning electron microscope) and TEM (transmission electron microscope).
It was observed that Cu impurities were adsorbed on Si surface not in a thin
film but in a particle form as a hemispherical shape. The chemical
composition of Cu impurities and interface between Cu and Si substrate was
investigated by AES (Auger electron spectroscope). The result exhibited that
Cu element adsorbed on Si surface by chemical adsorption and this resulted
in oxidation of Si substrate.
Comparison and Reproducibility of H-Passivation of Si(100) with
HF in Methanol, Ethanol, Isopropanol and Water by IBA, TMAFM, and
FTIR'
Authors: Atluri V. , Herbots N. , Dagel D. , Jacobsson H. , Johnson M. , Carpio R. , Fowler B. 
Published: April 2011

ABSTRACTThree different HF:alcohol solutions are investigated to etch native
SiO2 and passivate Si(100) surfaces with H which can the be
desorbed at low temperature (T < 600°C). The resulting passivated Si(100)
surfaces are compared using as a reference Si(100) passivated by a standard
aqueous HF: solution (1:98 parts of HF: H2O). After a modified
RCA cleaning, Si(100) etched by HF:Methanol, HF:IPA, or HF:Ethanol, is
characterized by Ion Beam Analysis (IBA), Tapping Mode Atomic Force
Microscope (TMAFM), and Fourier Transform Infrared Spectroscopy (FTIR). The
absolute coverage of O and C is measured by nuclear reaction analysis (NRA)
combined with ion channeling at 3.05 MeV for O and 4.265 MeV for C. Hydrogen
is measured via the elastic recoil detection (ERD) of
4He2+ at 2.8 MeV.Compared to aqueous HF, HF:alcohol passivates Si(100) leaving a lower O
residue by an average factor of 0.62 and a similar C residue. H coverage is
higher by an average factor of 1.43. Surface coverages are found to be
reproducible in average by 1.4 × 1014 atoms/cm2 for C,
and by 1.25 × 1014 atoms/cm2 for O when measured by
IBA on samples identically processed. H coverage is reproducible within 5.5%
when measured by ERD.Selective area analysis by TMAFM shows that an increasing number of
particulates is responsible for the apparent increase in root-mean -square
(rms) surface roughness when the rms is measured over a whole image. Taking
this effect into account, all passivated surfaces exhibit similar roughness
when compared to the original Si(100) surface with little difference between
alcohols and with the reference aqueous HF solution.FTIR in the attenuation total reflection (ATR) mode detected SiHx
species mostly as a dihydride. Both IBA and FTIR detected significant levels
of oxygen on surfaces passivated HF in alcohol and aqueous HF. This
indicates that while Si(100) exhibits more H when passivated with HF in
alcohol and can be desorbed at lower temperature than when treated with
aqueous HF, H is not bonded to Si only but likely bonds into a more complex
surface termination, such as SiOH.
Infrared Spectroscopy of Covalently Bonded Species on Silicon
Surfaces: Deuterium, Chlorine, and Cobalt Tetracarbonyl
Authors: Luo Huihong , Chidsey Christopher E. D. , Chabal Yves 
Published: April 2011

ABSTRACTWe report the formation of deuterium-terminated Si(111) and Si(100) surfaces
in deuterated aqueous KF. The reaction of a deuterated Si(100) surface with
H2O is investigated. We find that H2O etches the
surface to give hydrogen termination and oxidized silicon hydrides.
Hydrogenterminated surfaces react with various reagents under non-UHV
conditions to form other covalent bonded species, including Cl-Si and
Co(CO)4-Si. These species are characterized by polarized ATR
and transmission FTIR. On Cl-Si(111) surfaces, Cl-Si is perpendicular to the
surface. Chlorine-terminated Si(100) reacts with H2O to produce
the hydrogen terminated surface. On Co(CO)4-Si(111) surfaces, one
carbonyl is perpendicular to the surface, and the other three are
approximately parallel to the surface.
The use of Metal additions to Phosphoric Acid to Etch
Polysilicon in Poly Buffered Locos Processes
Authors: Pearce Charles W. , Chung B. C. 
Published: April 2011

ABSTRACTThe use of poly-buffered LOCOS processing is a common feature of many
sub-micron integrated circuit fabrication processes. However, the silicon
layer interposed between the nitride oxidation mask and the pad oxide is
often difficult to remove. Different strategies involve dry and/or wet
etching of the film. We have demonstrated the utility of adding metals such
as Fe or Cu to a conventional phosphoric bath used to etch silicon nitride.
Briefly, the presence of the metals is thought to result in a classic
oxidation-reduction reaction between the metal and the silicon. Additions of
60ppm of Cu+2 resulted in etch rates of 20Å /min. on undoped
polysilicon at a process temperature of 165°C, whereas, the etch rate of
SiO2 was less than 1Å/min. Similar results were obtained for
additions of Fe+3 and other metals.
Electrical Transport Properties of the Pentatelluride Materials Hfte5 and Zrte5
Authors: Tritt T. M. , Wilson M. L. , Littleton R. L. , Feger C. , Kolis J. , Johnson A. , Verebelyi D. T. , Hwu S. J. , Fakhruddin M. , Levy F. 
Published: April 2011

AbstractWe have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe5 and ZrTe5. We have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, Tp where Tp ≈ 80K for HfTe5 and Tp ≈ 145K for ZrTe5. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. This data is similar to behavior observed previously in these materials. We have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe5 and ZrTe5. We have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 μV/K and +65 μV/K for HfTe5 and ZrTe5 respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 μV/K for HfTe5 and +35 μV/K for ZrTe5. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T ≈ 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 mΩ-cm and 24 mΩ-cm for Hfre5 and ZrTe5 respectively, compared to single crystal values of 0.35 mΩ-cm (HfTe5) and 1.0 mΩ-cm (ZrTe5). We have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. We will discuss these materials in relation to their potential as candidates for thermoelectric applications.
High-Power Low-Threshold Optically Pumped Type-ll Quantum-Well Lasers
Authors: Lin Chih-Hsiang , Murry S. J. , Yang Rui Q. , Pei S. S. , Le H. Q. , Yan Chi , Gianardi D. M. , McDaniel D. L. , Falcon M. 
Published: April 2011

AbstractStimulated emission in InAs/InGaSb/InAs/AlSb type-II quantum-well (QW) lasers was observed up to room temperature at 4.5 μm, optically pumped by a pulsed 2-μm Tm:YAG laser. The absorbed threshold peak pump intensity was only 1.1 kW/cm2 at 300 K, with a characteristic temperature T0 of 61.6 K for temperatures up to 300 K. We will also study the effects of internal loss on the efficiency and output power for type-II QW lasers via optical pumping. Using a 0.98-μm InGaAs linear diode array, the devices exhibited an internal quantum efficiency of 67% at temperatures up to 190 K, and was capable of < 1. 1-W peak output power per facet in 6-μs pulses at 85 K. The internal loss of the devices exhibited an increase from 18 cm−1 near 70 K to ∼ 60–100 cm−1 near 180 K, which was possibly due to inter-valence band free carrier absorption.
Band-reject infrared metallic photonic band gap filters on flexible polyimide substrate
Authors: Gupta Sandhya , Tuttle Gary , Sigalas Mihail , Ho Kai-Ming 
Published: April 2011

AbstractMetallic photonic band gap (MPBG) structures are multi-layer metallic meshes imbedded in a dielectric medium. We report the successful design, fabrication, and characterization of infrared band-reject filters using MPBG structures in a flexible polyimide substrate. The metal layers of the MPBG have square grid patterns with short perpendicular cross-arm defects added halfway between each intersection. The transmission characteristics of these filters show a higher order band-reject region in addition to a lower order band gap that extends from zero to particular cut off frequency. The critical frequencies of the filters depend on the spatial periodicity of the metal grids and length of the cross-arm defects. Optical transmission measurements of the bandreject filters show lower edge cutoff frequency of about 2 THz and the higher order bandgap region centered around 4.5THz with attenuation of more than 35 dB in the bandgap region. This is in good agreement with the theoretical calculations. The filters maintain their optical characteristics after repeated bending, demonstrating mechanical robustness of the MPBG structure and have minimal dependence on angle of incidence.
HgCdTe– an Unexpectedly Good Choice for (Near) Room Temperature Focal Plane Arrays
Authors: Tennant W. E. , Cabelli C. 
Published: April 2011

AbstractFueled by a broad range of government needs and funding, HgCdTe materials and device technology has matured significantly over the last two decades. Also in this same time period, we have come to understand better the phenomenology which limits imager performance. As a result of these developments, it appears that HgCdTe arrays may be tailored in wavelength to outperform GaAs-based image intensifier devices in sensitivity and to compete with bolometric and pyroelectric imaging arrays in NEDT at temperatures at or near room temperature (250K–295K). These benefits can be fully realized, however, only if HgCdTe can be brought to a level of maturity where the material and detectors made from it are limited by fundamental mechanisms. We will discuss the state of HgCdTe near room temperature performance and the practical and theoretical limits which constrain it.
Quantum Well Intermixing for Optoelectronic Applications
Authors: Jagadish C. , Tan H. H. , Yuan S. , Gal M. 
Published: April 2011

AbstractIon implantation induced intermixing of GaAs-AlGaAs quantum well structures with H, O and As ions is investigated by low temperature photoluminescence. Large energy shifts are observed in all the cases, though recovery of photoluminescence intensities in proton case is more significant than others. Energy shifts are linear with proton dose and no saturation was observed even up to a dose of ∼ 5 × 1016 cm−2. Saturation in energy shifts are seen for both As and 0 ions at high doses. Energy shifts are also found to be dependent on Al composition of the barriers. Wavelength shifted quantum well lasers are fabricated with energy shifts of about 5 nm with no changes in threshold current using proton implantation. Anodic oxide induced intermixing of GaAs-AlGaAs quantum wells is demonstrated.
Effect of Geometric Factors on Polarization Properties of Vertical-Cavity Surface-Emitting Lasers With Tilted Pillar Structures
Authors: Park Min Soo , Ahn Byung Tae , Chu Hye Yong , Yoo Byueng-Su , Park Hyo-Hoon 
Published: April 2011

AbstractWe have studied the effect of geometric factors on the polarization properties of verticalcavity surface-emitting lasers with tilted pillar structures. Laser pillars with circular, square, diamond, and rectangular shapes were formed using reactive ion beam etching, by tilting the substrate with an angle of 15° ∼ 30° toward the [110] or [110] direction. We measured the polarization characteristics for the devices of 10 ∼ 20 atm size. We observed that an effective geometric factor on the polarization selectivity in tilted pillar structures is an asymmetric shape of vertical-cavity rather than an anisotropic shape of device area in planar direction.
Comparison Between Cadmium Zinc Telluride Crystals Grown in Russia and in the Ukraine
Authors: Hermon H. , Schieber M. , James R. B. , Yang N. , Antolak A. J. , Morse D. H. , Kolesnikov N. N. P. , Ivanov Yu. N. , Komar V. , Goorsky M. S. , Yoon H. , Toney J. , Schlesinger T. E. 
Published: April 2011

AbstractA comparative analysis of different Cd1−xZnxTe (CZT) crystals grown by a vertical high pressure Bridgman (VHPB) method is reported. The results of several analytical techniques, such as triple axis x-ray diffraction (TAD), rocking curves, low temperature photoluminescence (PL), scanning electron microscopy (SEM), and proton induced x-ray emission (PIXE) are discussed. Segregated carbon inclusions were identified by SEM and energy dispersive x-ray fluorescence (EDXRF), and the results are interpreted in terms of constitutional supercooling of the solidifying CZT melt. The carbon inclusions significantly decrease the resistivity, and in some cases, the noise is too large for the fabrication of radiation detectors. Combining these results with other measurements reported by our research team [1], we identify correlations between the growth and the defects identified in these CZT crystals.
Optical, Electrical and Surface Characterization of Mercuric Iodide Platelets Grown in the HgI 2-HI-H2O System
Authors: Fornaro L. , Chen H. , Chattopadhyay K. , Chen K.-T , Burger A. 
Published: April 2011

AbstractThe optical, electrical and surface properties of mercuric iodide platelets grown from solution in a HgI2-HI-H2O system were investigated by comparing them with Physical Vapor Transport (PVT) grown crystals. The absence of bulk imperfections and the uniformity of the as-grown surfaces and the KI solution etched surfaces were confirmed by optical microscopy. The as-grown surface uniformity is higher for solution grown crystals than that of PVT crystals, since the platelets do not have to be cleaved or polished. AFM studies show that the roughness for the cleaved, aged and etched surfaces were 0.06 nm, 0.48 nm and 0.3 nm respectively. Low temperature photoluminescence properties were measured for the two kind of crystals and will be discussed. However, I-V curves give higher current density and lower apparent resistivity values for the solution grown than for PVT grown crystals. Correlations between optical and surface quality as well as the electrical properties of the crystals grown from both solution and PVT methods are also discussed.
Enhancement of Mercuric Iodide Detector Performance Through Crystal Growth in Microgravity: the Roles of Lattice Order
Authors: Steiner Bruce , Berg Lodewijk Van Den , Laor Uri 
Published: April 2011

AbstractThe hole-mobility•carrier-lifetime product of α mercuric iodide high energy radiation detectors has been enhanced through vapor crystal growth in microgravity. This improvement is closely correlated with specific characteristics of the crystal lattice, which have been identified by high resolution synchrotron x-ray diffraction imaging. These structural features and the associated performance are now being approached in terrestrial growth of α mercuric iodide.Gravity may affect the uniformity of this crystal lattice in two distinct ways: 1) directly through deformation that it imposes on the lattice during growth and 2) indirectly through convection, which mixes any extraneous material. Inclusions associated with these processes harden the lattice and facilitate lattice folding. These changes affect the electronic parameters of detectors made from the crystals. As purification procedures are optimized, the incorporation of extraneous material is curtailed, enhancing electronic properties in spite of lattice flexing through loss of precipitation hardening.These studies provide insight into the contribution of various aspects of crystalline order in α-mercuric iodide crystals to property improvement. This knowledge has led to modification of requirements for starting materials, adjustment of physical vapor growth procedures, and change in crystal handling procedures. As a result, the electronic performance of terrestrially grown radiation detectors has been improved, and we provide evidence that further enhancement is still possible.
Modeling of the Signal Induced by an Incident Radiation in Semi-Insulating GaAs Detectors
Authors: Cola Adriano , Vasanelli Lorenzo , Reggiani Lino 
Published: April 2011

AbstractWe develop a Monte Carlo simulator of the charge signal induced by an external radiation on a semi-insulating GaAs detector. The role played by trapping and detrapping processes and the dynamics of generated carriers are investigated. The relative contribution to the charge signal of fast and slow time components as well as the time constant of the slow component are studied as a function of the applied voltage. Present findings provide a physical interpretation of available experimental results.
Possible Extensions of XIA'S Digital Spectrometer Technology to Portable and Remote Monitoring Instrumentation
Authors: Warburton W. K. , Darknell D. A. , Hubbard-Nelson B. 
Published: April 2011

AbstractThe XIA DXP-4C is a 4 channel, CAMAC based, x-ray spectrometer which digitally processes directly digitized preamplifier signals. The DXP-4C was designed for instrumenting multi-detector arrays for synchrotron radiation applications, and optimized for very high count rates at a low cost per detector channel. This produced a very compact and low power (3.4 W/channel) instrument for its count rate and MCA capabilities, which thus provides a strong basis for portable applications. Because all functions are digitally controlled, it can be readily adapted to various user interfaces, including remote access interfaces. Here we describe the design and examine approaches to lowering its power to 50 mW/channel. We then consider the issues in applying it to three typical portable or remote spectrometry applications.