bluuebunny/crossref_metadata_2025_split huggingface dataset:
Native Oxide Growth Behavior on Silicon Surface with Various
Resistivity in Ultrapure Water and CuF2 Solution
Authors: Sekine Katsuyuki , Choi Geun-Min , Saito Yuji , Ohmi Tadahiro 
Published: April 2011

ABSTRACTWe have studied native oxide growth behavior on silicon surface with various
resistivity in ultra pure water (UPW), SPM (sulfuric acid-hydrogen peroxide
mixture, H2SO4:H2O2 = 4:1)
cleaning and UPW contaminated with CuF2 by X-Ray photoelectron
spectroscopy (XPS). The results show that the native oxide growth behavior
in UPW is different from that in UPW contaminated with CuF2 and
that grown by SPM cleaning. Native oxide thickness grown in UPW depends on
resistivity. Native oxide thickness grown during SPM cleaning has the
relationship of steric hinderance effect. However, in CuF2
solution, native oxide thickness is more influenced by the redox reaction
between Cu ions and silicon atoms.
Utilizing Bath/Wafer Contamination Correlation to Validate a
Pre-Gate Cleaning Strategy
Authors: Gilton Terry , Higdon Clarence , Copsey Kate 
Published: April 2011

ABSTRACTThe correlation of contaminants in a process bath with contaminants on a
silicon wafer prepared in the bath is important information when developing
a cleaning strategy. In this paper, we present such a correlation focused on
contaminants in dilute HF (1:100) and in SC1 (1:1:5 and 1:1:80 at 50°C and
65°C). We have limited the contamination levels to between 0 and 150 ppb. We
have also limited the contaminants studied to those that are most likely to
be a problem (Fe, Al, Mg, Ca, Cu, Zn, and Na). The bath concentrations are
measured using ICPMS and the wafer surface concentrations are measured using
both VPD/TXRF and VPD/ICPMS.We demonstrate that Fe and Ca at the levels studied do not deposit from
dilute HF, while Cu deposits, showing a linear dependence on bath
concentration. We also demonstrate that in the SCl bath, both concentration
and temperature are important variables in the contamination of wafers for a
given bath contamination level. Al and Zn contaminate wafers most strongly,
with Al being the largest contributor at the higher concentration of SC1 and
Zn being the largest contributor in the lower concentration. Finally, we
demonstrate that a dilute HF clean can remove everything deposited in a
highly contaminated SC1 bath.
The Formation of Water Marks on Both Hydrophilic and Hydrophobic
Wafers
Authors: Park Jin-Goo , Han Jeung-Hoon , Kim Seung-Hwan , Lee Sang-Ho 
Published: April 2011

ABSTRACTThe purpose of this paper is to explore the formation of water residues on
wafers during drying. To investigate this DI water droplets were
intentionally placed on the surface of substrates with various wettabilities
and then left to dry in both N2 and O2 atmospheres. It
was found that both hydrophobic and hydrophilic surfaces created the water
mark in N2 and O2. The size and dry time of residues
were dependent on the wettability of surfaces. Auger analysis of residues
showed that the oxidation of surface in water might be one of causes of
water mark formation. Considering the pore size of final filters in DI water
generation is 0.05 μn, a large number of particles less than 0.05 μm ay be
in DI water. In order to investigate the effect of small particles less than
0.05 μm on water mark formation, PSL particles less than 0.05 μm were added
to DI water. DI water containing particles was left to dry as a function of
particle concentrations. The size of water marks was dependent on the
concentration of particles in DI water after they reached a critical
concentration.
Surface Treatment with UV-Excited Radicals for Highly-Reliable
Gate Dielectrics
Authors: Ito Takashi , Sugino Rinji , Nakanishi Toshiro , Ohkubo Satoshi , Tamura Yasuyuki , Takasaki Kanetake 
Published: April 2011

ABSTRACTThe UV-excited chlorine radical treatment effectively removed trace metal
contaminants from Si ans SiO2 surfaces. We have found that this
is predomonantly attributed to reactions between metal and chlorine, and
metal oxides and silicon chloride, respectively. The former process was
subjected to identify a breakdown spot on a thin gate dielectric film. After
dielectric breakdown, a silicon crystallized filament as small as a few
nanometers in diameter was formed and was selectively etched with chlorine
radicals revealing a successively-etched region of the Si substrate.
Nonuniformities of native exides on silicon were also detected using the
same method. Gettering and etching wi:h a poly Si layer showed a possibility
to make a gate dielectric film damage free and contamination free.
Densification of native oxides formed after conventional wet cleaning of
silicon was made with UV-excited oxygen radicals. Electrical characteristics
of gate dielectrics treated with UV-excited chlorine and oxygen radicals
showed high reliability.
Development of BI-SB-TE Ternary Alloy with Compositionally Graded Structure
Authors: Yamamoto A. , Ohta T. 
Published: April 2011

AbstractCompositionally graded p-type Bi-Sb-Te thermoelectric material was synthesized by PIES (Pulverized and Intermixed Elements Sintering) method. The materials consisted of three segmented regions of different alloy composition, i.e. y = 0.8/0.825/0.9 in (Bi2Te3)1−y(Sb2Te3)ysystem. It was found that the electrical power output of the compositionally graded material was larger than that of the best single composition material when the temperature difference was the designed value.
Microstructure, Mechanical Properties, and Thermoelectric Properties of Hot-Extruded P-Type Te-Doped Bi0.5Sb1.5Te3 Compounds
Authors: Park K. , Seo J. , Lee C. 
Published: April 2011

AbstractThe p-type Bi0.5Sb1.5Te3 compounds with Te dopant (4.0 and 6.0 wt%) and without dopant were fabricated by hot extrusion in the temperature range of 300 to 510 °C under an extrusion ratio of 20:1. The undoped and Te doped compounds were highly dense and showed high crystalline quality. The grains contained many dislocations and were fine equiaxed (˜ 1.0 μm) owing to the dynamic recrystallization during the extrusion. The hot extrusion gave rise to the preferred orientation of grains. The bending strength and the figure of merit of the undoped and Te doped compounds were increased with increasing the extrusion temperature. The Te dopant significantly increased the figure of merit. The values of the figure of merit of the undoped and 4.0 wt% Te-doped compounds hot extruded at 440 °C were 2.11×10−3/K and 2.94×10−3/K, respectively.
Thermoelectric Properties of M2Mo6Se6 (M=TI, In)
Authors: Verebelyi D. T. , Payne J. E. , Tessema G. X. , Mengistu E. 
Published: April 2011

AbstractWe have measured the thermal conductivity of TI2Mo6Se6, a quasi-one dimensional conductor which belongs to the family of M2Mo6X6 linear chain compounds. Using these results and our measurements of the Seebeck coefficient and the electrical conductivity we estimate the dimensionless figure of merit to be of the order of 0.08. This result suggest that this compound and other related compounds are good potential TE.
The Thermoelectric Process
Authors: Vining C. B. 
Published: April 2011

AbstractThe efficiency of thermoelectric technology today is limited by the properties of available thermoelectric materials and a wide variety of new approaches to developing better materials have recently been suggested. The key goal is to find a material with a large ZT, the dimensionless thermoelectric figure of merit. However, if an analogy is drawn between thermoelectric technology and gas-cycle engines then selecting different materials for the thermoelements is analogous to selecting a different working gas for the mechanical engine. And an attempt to improve ZT is analogous to an attempt to improve certain thermodynamic properties of the working-gas. An alternative approach is to focus on the thermoelectric process itself (rather than on ZT), which is analogous to considering alternate cycles such as Stirling vs. Brayton vs. Rankine etc., rather than ‘merely’ considering alternative ‘gases’. Focusing on the process is a radically different approach compared to previous studies focusing on ZT. Aspects of the thermoelectric process and alternative approaches to efficient thermoelectric conversion are discussed.
Thermal Conductivity and Heat Transfer in Superlattices
Authors: Chen G. , Neagu M. , Borca-Tasciuc T. 
Published: April 2011

AbstractUnderstanding the thermal conductivity and heat transfer processes in superlattice structures is critical for the development of thermoelectric materials and devices based on quantum structures. This work reports progress on the modeling of thermal conductivity of superlattice structures. Results from the models established based on the Boltzmann transport equation could explain existing experimental results on the thermal conductivity of semiconductor superlattices in both in plane and cross-plane directions. These results suggest the possibility of engineering the interfaces to further reduce thermal conductivity of superlattice structures.
Multivalent Acceptor-Doped Germanium Lasers: a solid-state tunable source from 75 to 300 μm
Authors: Chamberlin D. R. , Dubon O. D. , Bründermann E. , Haller E. E. , Reichertzl L. A. , Sirmain G. , Linhart A. M. , Röser H. P. 
Published: April 2011

AbstractWe report on the performance of far-infrared hole inversion lasers made from germanium doped with the multivalent acceptors beryllium and copper. Commonly used hole inversion lasers are made from Czochralski-grown Ga-doped Ge single crystals and show emission from 75 to 125 and 170 to 300 μm. The emission gap between 125 and 170 μm, originating from absorption of the far-infrared light due to internal hole transitions in the neutral Ga acceptor, is absent in the new Be and Cu-doped lasers. We also find a mechanism for inversion depopulation through neutral Ga which hinders lasing at low electric fields. This same mechanism is shown to cause population inversion in the Be-doped laser and allows lasing at lower fields. This reduces the power input into the germanium crystal and has allowed us to increase the duty cycle up to 2.5% which is one order of magnitude higher than the maximum duty cycle reported for Ga-doped Ge lasers. These new lasers may offer an opportunity for achieving continuous-wave operation.In addition we have performed preliminary studies on the effect of uniaxial stress on the lasing in these new materials. We demonstrate that small uniaxial stress increases laser action in Ge:Cu. We propose that this is due to an increased population inversion because under these conditions two separate mechanisms cause heavy holes to enter the light hole band.
Bandgap-Engineering of HgCdTe for Two-Color Ir Detector Arrays BY Movpe
Authors: Mitra P. , Case F. C. , Barnes S. L. , Reine M. B. , O'Dette P. , Tobin S. P. 
Published: April 2011

AbstractRecent results on MOVPE growth of multilayer two-color HgCdTe detectors, for simultaneous and independent detection of medium wavelength (MW, 3–5 μm) and long wavelength (LW, 8–12 μm) bands, are reported. The structures are grown in situ on lattice matched (100) CdZnTe in the double-heterojunction p-n-N-P configuration. A barrier layer is placed between the LW and MW absorber layers to prevent diffusion of MW photocarriers into the LW junction and thereby eliminate spectral crosstalk. X-ray double crystal rocking curve widths are ∼ 45 arc-secs, indicating good epitaxial quality. SIMS depth profile measurements of these 28 μm thick structures show well-defined alloy compositions, and arsenic and iodine doping. SIMS data on a series of thirteen films show that good run-to-run repeatability is obtained on thicknesses, compositions, and dopant levels with values close to the device design targets. Depth profile of etch pits through the thickness of the films show etch pit densities in the range of 8×105-5×106 cm−2.
In Situ Spectroscopic Ellipsometry for Real Time Composition Control of Hg1−xCdxTe Grown by Molecular Beam Epitaxy
Authors: Dat R. , Aqariden F. , Duncan W. M. , Chandra D. , Shih H. D. 
Published: April 2011

AbstractSpectral ellipsometry (SE) was applied to in situ composition control of Hg1−xCdxTe grown by molecular beam epitaxy (MBE), and the impact of surface topography of the Hg1−xCdxTe layers on the accuracy of SE was investigated. Of particular importance is the presence of surface defects, such as voids in MBE- Hg1−xCdxTe layers. While dislocations do not have any significant impact on the dielectric functions, the experimental data in this work show that MBE- Hg1−xCdxTe samples having the same composition, but different void densities, have different effective dielectric functions.
On the Moss-Burstein Shift In Quantum Confined Optoelectronic Ternary and Quaternary Materials
Authors: Ghatak Vamakhya P. , Bose P. K. , Majumder Gautam 
Published: April 2011

AbstractIn this paper we have studied the Burstein-Moss shift in quantum wires and dots of ternary and quaternary materials on the basis of a newly formulated electron dispersion law which occurs as a consequence of heavy doping. It is found taking Hg1−xCdxTe and In1−xGaxAsyP1−y lattice matched to InP as examples that the Burstein-Moss shift exhibits oscillatory dependences for quantum wires and dots of the said materials with respect to doping and film thickness respectively. Besides, the numerical values of the same shift is greatest in quantum dots and least in quantum wires. In addition, the theroretical analysis is in agreement with the experimental datas as given elsewhere.
Modified Vapor Phase Growth of Cadmium Zinc Telluride: A Progress Report
Authors: Trower W. P. 
Published: April 2011

AbstractWe have completed a series of experiments where we realized Cd(1−x)ZnxTe by modified Vapor Phase Growth in which the CdTe and ZnTe components were separated in the growth ampoule, with their vapors passing through channels and openings designed to mix them stoichiometrically at the growth surface. We have obtained polycrystalline CZT boules 50 mm in diameter and 10 mm high whose structure is strikingly different from that obtained by standard High Pressure Bridgman methods. Our mVPG properties relevant for detector applications include resistivity of∼40 GΩ-cm when voltage is first applied, rising to ∼66 GΩ-cm after ∼20 min when the traps are filled, and electron mobility-lifetimes of∼2 × 10−3 cm2/ν. Here we present some structural and operational characterizations of our mVPG CZT.
Analyses of Compensation Related Defects in II-VI Compounds
Authors: Castaldini A. , Cavallini A. , Fernandez P. , Fraboni B. , Piqueras J. 
Published: April 2011

AbstractThe deep levels present in semiconducting CdTe and semi-insulating (SI) CdTe:Cl and Cd0.8Zn0.2 Te have been investigated by means of cathodoluminescence (CL), deep level transient spectroscopy (DLTS), photo-DLTS (PDLTS) and photo induced current transient spectroscopy (PICTS). PICTS and PDLTS can be applied to SI materials and allow to determine whether the observed deep levels are hole or electron traps.Among the observed deep centers, we have focused our attention on those involved in the compensation process such as the so called center A and the deep traps located near midgap. We have identified a deep acceptor, labelled H, and a deep donor, labelled E, the latter is peculiar to CdTe:Cl and can be a good candidate for the deep donor level needed to explain the compensation process in SI CdTe:Cl.
Control of Defects and Impurities in Production of CdZnTe Crystals by the Bridgman Method
Authors: Glass H. L. , Socha A. J. , Bakken D. W. , Speziale V. M. , Flint J. P. 
Published: April 2011

AbstractCadmium zinc telluride crystals were grown by vertical Bridgman processes using in situ compounding from high purity elements into pyrolytic boron nitride crucibles within sealed fused quartz ampoules containing cadmium vapor at a pressure of roughly one atmosphere. These conditions produce material having the low etch pit density, low precipitate density, high infrared transmission and high purity required for use as substrates for infrared focal plane detector arrays fabricated in epitaxial mercury cadmium telluride. Similar processes should be satisfactory for producing cadmium zinc telluride for gamma ray detectors.
Radiation Damage of Amorphous and Microcrystalline Silicon Image Sensor Structure
Authors: Kolodziej A. , Krewniak P. 
Published: April 2011

AbstractThe paper reports radiation damage experiments which influence properties of image sensors using pin photodiodes and thin film transistors. The effect of 60Co radiation at about 1.2MeV on the noise and drain-source current characteristics of hydrogenated amorphous and nanocrystalline silicon film transistor was examined as a function of the γ dose and hydrogen content of the films.An unmeasurable effect upon the noise characteristics of the TFT was observed. The predominant drain-source current with increasing dose was in the form of various shifts of the transfer characteristics toward negative gate voltage and decrease of the transfer characteristic subthreshold slope from 5at% to 26at% of hydrogen content in the films. These, in turn, resulted in a large increase in leakage current for gate voltages at the periods the TFTs were not conducting. The radiation damage of the pin diode has much less influence on operation of array than the damage of the TFT.Annealing for 3h at 180°C restored TFT threshold voltage properties, particularly in the case of amorphous films with greater contents of hydrogen.
Applicability of Shallow-Impurity Doped Silicon to Proton Flux Sensors Using Stable Particle-Induced Conductivity
Authors: Kishimoto N. , Amekura H. , Kono K. , Lee C. G. 
Published: April 2011

AbstractHigh-energy particles incident to a semiconductor sensitively produce electron-hole pairs and the excited current has been used for radiation detectors. Although semiconductors have advantages such as high sensitivity and fast response, a drawback is weakness in radiation damage. To improve the radiation resistance, effects of shallow-impurity doping was explored for Si. Specimens of CZ-Si doped with P or B were bombarded with 17 MeV protons. The radiation-induced current of doped Si has been evaluated, as a function of proton fluence. The signal of particle-induced conductivity showed a fairly constant response to a proton flux, up to 1015 ions/cm2. The fluence range applicable as Si sensors was extended 103-104 times as much as that of non-doped Si, instead of a lower signal-to-noise ratio. Shallow impurities passivate the deep centers of radiation-induced defects, and the radiation tolerance continues until the pre-existent carriers are exhausted. The tolerant fluence is also usable to detect the integrated fluence, by controlling the initial impurity concentration.
High Collection Efficiency Thin Film Diamond Particle Detectors
Authors: Bergonzo P. , Foulon F. , Marshall R. D. , Jany C. , Brambilla A. , Mckeag R. D. , Jackman R. B. 
Published: April 2011

AbstractDiamond is a resilient material with rather extreme electronic properties. As such it is an interesting candidate for the fabrication of high performance solid state particle detectors. However, the commercially accessible form of diamond, grown by chemical vapour deposition (CVD) methods, is polycrystalline in nature and often displays rather poor electrical characteristics. This paper considers ways in which this material may be used to form alpha particle detectors with useful performance levels. One approach adopted has been to reduce the impurity levels within the feed-stock gases that are used to grow the diamond films. This has enabled significant improvements to be achieved in the mean carrier drift distance within the films leading to alpha detectors with up to 40% collection efficiencies. An alternative approach explored is the use of planar device geometries whereby charge collection is limited to the top surface of the diamond which comprises higher quality material than the bulk of the film. This has lead to collection efficiencies of 70%, the highest yet reported for polycrystalline CVD diamond based detectors. Techniques for improving the characteristics of these devices further are discussed.
Deep Levels Induced by High Fluence Proton Irradiation in Undoped GaAs Diodes
Authors: Castaldini A , Cavallini A , Polenta L , Canali C , Nava F , Ferrini R , Galli M 
Published: April 2011

AbstractSemi-insulating liquid encapsulated Czochralski grown GaAs has been investigated after irradiation at high fluences of high-energy protons. Electron beam induced current observations of scanning electron microscopy evidenced a radiation stimulated ordering. An analysis has been carried out of the deep levels associated with defects as a function of the irradiation fluence, using complementary current transient spectroscopies. By increasing the irradiation fluence, the concentration of the native traps at 0.37 eV together with that of the EL2 defect significantly increases and, at the same time, two new electron traps at 0.15 eV and 0.18 eV arise and quickly increase in density.
In Situ Spectroscopic Ellipsometry for Real Time Composition Control of Hg1−xcdx Te Grown by Molecular Beam Epitaxy
Authors: Dat R. , Aqariden F. , Duncan W. M. , Chandra D. , Shih H. D. 
Published: April 2011

AbstractSpectral ellipsometry (SE) was applied to in situ composition control of Hg1−xCdxTe grown by molecular beam epitaxy (MBE), and the impact of surface topography of the Hg1−xCdxTe layers on the accuracy of SE was investigated. Of particular importance is the presence of surface defects, such as voids in MBE- Hg1−xCdx.Te layers. While dislocations do not have any significant impact on the dielectric functions, the experimental data in this work show that MBE- Hg1−xCdxTe samples having the same composition, but different void densities, have different effective dielectric functions.
Recent Improvements in Dry Etching of Hg1−xCdxTe By Ch4 Based Electron Cyclotron Resonance Plasmas
Authors: Seelmann-Eggebert M. , Rar A. , Zimmermann H. , Meisen P. 
Published: April 2011

AbstractSignificant improvements of a previously reported etching process [1] for Hg1−xCdxTe have been achieved with respect to etch rate, surface morphology and surface stoichiometry by optimization of the process parameters. The gas phase and surface reactions driving the etching process have been analyzed by combined optical and electrical characterization of the plasma and surface analyses of the samples. A reaction scheme is suggested which allows to model and upscale the process in a consistent manner.
Use Of A Capillary X-Ray Focused Beam To Investigate The Chemical Composition Of CdZnTe Wafers With High Resolution CdZnTe Detectors
Authors: Fougères P. , Burggraf Ch. , Burggraf Chr. , Koebel J. M. , Koenig C. , Regal R. , Hage-Ali M. , Krauth A. , Siffert P. 
Published: April 2011

AbstractThe control of the concentration of Zn and its fluctuation in the high pressure Bridgman grown CdZnTe crystals is part of our characterization work on the ternary grown ingots grown in house. In order to reach both high sensitivity and high position resolution, we have developed a new system consisting of a X-ray generator, coupled to a focusing X-ray capillary, delivering intense beams in the micron scale, since the intensity gain is around a factor of 100 compared to conventional methods.The characteristic X-rays are measured through a high resolution CdZnTe detector (225 eV at 5.9 keV FWHM) cooled by a Peltier system. The results of our investigations on different kinds of crystals will be discussed.