bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Si, F Implantation on the Formation and Light Emitting Properties of Porous Silicon
Authors: Wang Lianwei , Lin Chenglu , Liu Ping , Zhou Zuyao , Zou Shichang 
Published: March 2011

Abstract:The effect of ion implantation on the formation and light emitting properties of porous silicon is reported. Si + , F+ ions were implanted into silicon wafers before electrochemical etching process. The experiments showed that porous structure can be formed on the wafer containing amorphous layer, while the porosity distribution with the depth changed greatly compared with the anodized crystalline Si. The implantation of F+ ions greatly affects the formation mechanism. The creation of point defects leads to red-shift in photoluminescence measurements.
Host Guest Interactions in Ti-Implanted Silica, Borosilicate and Aluminosilicate Glasses
Authors: Henderson D. O. , Morgan S. H. , Mu R. , Collins W. E. , Magruder R. H. , White C. W. , Zuhr R. A. 
Published: March 2011

ABSTRACTTitanium oxide glasses exhibit a significant nonlinear optical response which is attributed to the large polarizability of the Ti ion. Ion implantation is a unique method for incorporating polarizable ions in glass hosts and allows for tailoring the nonlinear optical properties of the material for potential device applications in all optical switching and planar waveguide technology. However, at the molecular level, the linear and nonlinear properties of ion implanted glasses are governed by interactions between the glass host and the implanted ion, radiation damage, and ion-glass chemistry. In order to probe the host-guest interactions, we have measured the infrared and optical spectra for Ti implanted in silica, borosilicate, and aluminosilicate glasses. The infrared and optical spectra indicate that the host-guest interactions and defect concentration differ significantly for the three glasses investigated.
Nano-Structure Ge Formed in Thin Film SiO2 Using Ion Implantation
Authors: Phillips J.R. , Hellman Olof C. , Kobayashi N. , Makita Yunosuke , Shibata Hajime , Yamada A. , Fons P. , Tsai Yushin , Niki Shigeru , Hasegawa Masataka , Iida Tsutomu 
Published: March 2011

ABSTRACTThe preparation of amorphous insulating films containing nanometer-scaled structures of semiconductors has attracted increased attention since the observation of room temperature emission of light from films containing indirect-bandgap semiconductors such as Ge and Si. While most experimental reports on these Si and Ge nano-scale structures have been based on thin films created using sputter-deposition, in this study we have used conventional ion implantation of Ge to create the non-equilibrium mixture of materials that, upon annealing, develops a nano-crystallite phase embedded in the amorphous matrix. The presence of clusters that are difficult to image in TEM, in addition to microcrystallites, is an issue of interest since the source of light emission is still controversial. The second phase is formed from excess amounts of the semiconductor, in this case added by implantation. In this paper the formation and size distribution of the Ge nano-structures was characterized using Raman scattering and transmission electron microscopy (TEM). Similarly to reported sputtered film results, Raman spectra suggest Ge clusters that are not well formed crystallites may be present for anneals at low temperatures and in unannealed films. For annealing temperatures exceeding 600°C, a mixture of amorphous-like clustering and nano-crystallites may result, depending on the volume fraction of Ge. For low dose samples it was found that temperature and time of annealing could be used to manipulate the nucleation behavior of the nano-crystallites.
Oriented Si and Ge Nanocrystals Formed in Al2O3 by Ion Implantation and Annealing
Authors: White C.W. , Budai J.D. , Withrow S.P. , Pennycook S.J. , Hembree D.M. , Zhou D.S. , Vo-Dinh T. , Magruder R.H. 
Published: March 2011

ABSTRACTIon implantation followed by thermal annealing in a reducing atmosphere has been used to create a high density of oriented Si and Ge nanocrystals in (0001) AI2O3. Both types of nanocrystals are three-dimensionally aligned with respect to the AI2O3 matrix, but the orientational relationships are different, and the two types of nanocrystals have different shapes in AI2O3. Implantation of Si and Ge in fused silica also produces nanocrystals, but in this case, the nanocrystals are randomly oriented relative to each other.
First Results from the Los Alamos Plasma Source Ion Implantation Experiment
Authors: Rej D. J. , Conrad J. R. , Faehl R. J. , Gribble R. J. , Henins I. , Horswill N. , Kodali P. , Nastasi M. , Reass W. A. , Shamim M. , Sridharan K. , Tesmer J. R. , Walter K. C. , Wood B. P. 
Published: March 2011

ABSTRACTA new facility is operational at Los Alamos to examine plasma source ion implantation on a large scale. Large workpieces can be treated in a 1.5-m-diameter, 4.6-m-Jong plasma vacuum chamber. Primary emphasis is directed towards improving tribological properties of metal surfaces. First experiments have been performed at 40 kV with nitrogen plasmas. Both coupons and manufactured components, with surface areas up to 4 m2, have been processed. Composition and surface hardness of implanted materials are evaluated. Implant conformality and dose uniformity into practical geometries are estimated with multidimensional particle-in-cell computations of plasma electron and ion dynamics, and Monte Carlo simulations of ion transport in solids.
A New Computationally-Efficient 2-D Model for Boron Implants into (100) Single-Crystal Silicon
Authors: Morris Steven J. , Yang Shyh-Horng , Lim David H. , Tasch AL. F. 
Published: March 2011

ABSTRACTIn this paper, the first comprehensive and computationally-efficient two-dimensional model is reported for boron implants into (100) single-crystal silicon with explicit dependence on energy, dose, implant angles, mask height, mask orientation, and rotation of the wafer during the implant. The model and its implementation into SUPREM 4 are described, and where possible, the explicit dependencies are illustrated.
Visualization of Ion Channeling of (100)Si and Si1-xGex Epitaxial Grown Layers on Silicon
Authors: Xu M. , Atzmon Z. , Schroer A. , Wilkens B. , Mayer J.W. 
Published: March 2011

ABSTRACTThree dimensional visualization of ion channeling spectra was obtained by computer graphics in order to observe the crystalline quality and the strain state of thin films. Pure (100)Si and Si1-xGex (x=0.10, 0.18) layers, epitaxially grown on (100)Si substrates, were channeled along the <110> crystal axis with the 2 MeV He++ ion beam in a UHV target chamber. The data were interpolated using a standard bicubic tensor product B-spline surface with uniform knot sequences in x and y directions. With this modeling technique we have shown the orientation of the major planes in a diamond crystal and the angular displacement of the Ge signal in the SiGe epilayer relative to the Si substrate signal due to the presence of tetragonal distortion in the epilayer.
Damage Accumulation in MgAl2O4 Crystals by Xe Ion Irradiations
Authors: Yu N. , Nastasi M. , Hollander M.G. , Evans C.R. , Maggiore C.J. , Sickafus K.E. , Tesmer J.R. 
Published: March 2011

ABSTRACTWe have studied the damage kinetics in single crystal MgAl2O4 (spinel) with (100) orientation under 370 keV Xe ion irradiations at temperatures of -100 and 400 C. In-situ Rutherford Backscattering Spectrometry (RBS) and ion channeling have been used to monitor the damage accumulation in spinel following sequential Xe ion irradiations. A significant temperature effect on the irradiation damage has been found. Channeling data show that at -100 C, the irradiated spinel layer reaches the same level as in a random spectrum at a dose of 8×1015 Xe/cm2 (20 DPA for peak damage), while at 400 C, the near surface region (50 nm) remains single-crystalline up to 2×1016 Xe/cm2.
Experimental Study of Precipitation Processes in Oxygen Implanted Silicon
Authors: Weber R. , Yankov R. , Müller R. , Skorupa W. , Reiss S. , Heinig K.-H. 
Published: March 2011

ABSTRACTSingle crystal (100) silicon substrates were implanted at 300 keV with substoichiometric oxygen doses ranging from 1 × 1016 to 1 × 1017 cm-2. Samples were annealed for 2 hours over the temperature range from 1100°C to 1250°C and were subsequently analysed by both cross sectional transmission electron microscopy (XTEM) and scanning electron microscopy (SEM). The nucleation and growth of oxide precipitates within the implanted layer was followed during annealing. The emphasis was placed upon studying the process of Ostwald ripening which is known to play an important role in the formation of the incipient buried layer. Besides, a clear trend of the SiO2 precipitates to arrange in well defined regions was revealed and this was attributed, as distinct from the earlier claims, to an inherent process of self organisation.
Synthesis of (SIC)3N4 Films by Ion Implantation
Authors: Uslu C. , Lee D. H. , Berta Y. , Park B. , Thadhani N. N. , Poker D. B. 
Published: March 2011

ABSTRACTWe have investigated the synthesis of carbon-silicon-nitride compounds by ion implantation. In these experiments, 100 keV nitrogen ions were implanted into polycrystalline β-SiC (cubic phase) at various substrate temperatures and ion doses. These thin films were characterized in detail by x-ray diffraction with a position-sensitive detector, transmission electron microscopy with chemical analysis, and Rutherford backscattering spectroscopy. The as-implanted samples show a buried amorphous layer at a depth of 170 nm. The peak concentration of nitrogen saturates at approximately 45 at. % with doses above ~9.0×1017 N/cm2 at 860°C. These results suggest formation of a new phase by nitrogen implantation into β-SiC.
Low Energy Ion Beam Assisted Deposition of Low Resistivity Aluminum Using TMAA
Authors: Yan H. Q. , Wang H. , Steckl A. J. 
Published: March 2011

ABSTRACTThermal deposition and Ga+ ion beam assisted deposition of Al using TMAA have been studied. At temperatures between 95ºC and 105ºC, where thermal deposition is negligible, the introduction of a low energy Ga+ ion beam (8 to 10 keV) produces selective deposition. Ion beam seeding followed by ion beam irradiation during TMAA flow leads to consistent selectivity at this temperature range. The lowest resistivity of selectively deposited Al film is 7 µΩ-cm, only 2.5 times the bulk Al resistivity. The selective deposition rate is about 300Å/min. Depositions at higher temperature produced very low resistivity Al films, but with a decreasing selectivity ratio. X-ray diffraction showed that deposited Al films are polycrystalline, with very small FWHM.
Details of the Defect Profile in Self-ion Implanted Silicon
Authors: Zhang P.X. , Goldberg R.D. , Mitchell I.V. , Schultz P.J. , Lockwood D.J. 
Published: March 2011

ABSTRACTRaman spectra excited at two laser wavelengths are used to study the damage in self-implanted silicon. It was found that the contributions from the damaged surface crystalline and a-Si layers can be distinguished and separated, based on the different light absorption coefficients. A defect-activated low frequency band in the damaged surface crystalline Si layer was revealed. In totally amorphized samples the Raman spectra excited by 457.9 and 647.1 nm show different scattering intensity ratios for the optical- and acoustic-like-phonons. This novel result seems to indicate a depth dependent variation of the disordering in the amorphous layer.
Development of an Atomic Oxygen Source for Thin Oxide Film Formation
Authors: Inoue S. , Kawagoe Y , Yamanishi K. , Tanaka M. 
Published: March 2011

ABSTRACTAtomic oxygen promotes the oxidation of thin films. The authors developed a silent discharge type atomic oxygen source for thin oxide film formation. The atomic oxygen source consists of a quartz discharge tube and two cylindrical electrodes that are attached to the outside wall of the tube. The atomic oxygen concentration is estimated to be 3%.The atomic oxygen source was installed in an ICB (Ionized Cluster Beam) apparatus and applied to the formation of Er-Ba-Cu-0 thin films. By introducing the atomic oxygen during deposition, a film showing superconductivity at 81K was obtained when the substrate temperature was 570ºC. Also the substrate temperature to obtain a film showing superconductivity at 77K was estimated to be 50 °C lower than that for obtaining superconducting film formation in an atmosphere of 6% ozone. The atomic oxygen source was also applied to SrTiO3 thin film formation. Electrical properties of this film were examined and compared with those of films prepared in an atmosphere of 6% ozone. The dielectric constant of SrTiO3 film was improved from 60 to 180 by introducing atomic oxygen instead of 6% ozone. Therefore the atomic oxygen source was proven to be advantageous for thin oxide film formation.
Hard Carbon Films with Various Microstructure Prepared by Ion Assisted Evaporation
Authors: Ullmann J. , Weber A. , Falke U. 
Published: March 2011

ABSTRACTFor a deeper understanding of the creation of carbon films the hydrogen-free ion assisted evaporation (IAE) method with neon species was used. Variation of the ion parameters energy and ion to neutral arrival ratio, delivering the necessary energy for modification of the film growth, results in different microstructures investigated with EELS, HRTEM and TED as well as different microhardnesses measured by dynamical Vickers indentation. A possible film growth mechanism is proposed based on an ion etching of mainly sp2-bonded carbon surface atoms and on defect dominated structure modification below the surface depending on the ion energy
TiOxCy Thin Film Deposition by CO2+-Ion Beam Sputtering of Titanium
Authors: KEMPF BERTILO E. 
Published: March 2011

ABSTRACTTitanium metal is sputtered by ion beams using a Kaufman-type ion source with carbondioxide as working gas. Deposition takes place on watercooled substrates of silicon and InP. The films obtained are amorphous; they adhere excellently. SEM-pictures reveal a featureless dense fracture and a smooth surface. Despite a carbon content of 9 at % the films are highly transparent in the visible and near infrared wavelength range. Refractive indices center around 2.15 at values typically found for amorphous TiO2. The electrical properties are characterized by dielectric constant of ε = 26 ± 3, leakage current densities at breakdown of jL = 3.65 . 10-3 A/cm2 and breakdown fields EB > 1 MeV/cm.
Fabrication of W/C Multilayers by Direct Ion Beam Deposition
Authors: Ito K. , Nishimoto K. , Watanabe K. , Kataoka I. , Widmann Frédéric 
Published: March 2011

ABSTRACTThe multilayer structures of tungsten and carbon for soft x-ray mirrors were fabricated by the low energy (<100eV) direct ion beam deposition method with various depositing ion energies. The layered structures were observed by cross sectional TEM. The undulated structures were found in the layered structures of the depositing ion energy of 6OeV and lOOeV. It becomes larger as the depositing ion energy increases, and the undulation of the upper layers was larger than that of the under layers. The undulation seems to increase in each carbon layer. These results are quite different from the results of evaluation of thick monolayer films in the previous work. Then, the interfacial composite layer was evaluated by XPS. The tungsten carbide layer was found at the W/ C interface on the C layer. However, we can not find such layer at the interface on the W layer. This result can be explained by the difference of the momentum of the depositing ion.
Intra-Cascade Surface Recombination of Point Defects During Ion Bombardment of Ge (001)
Authors: Floro J. A. , Kellerman B. K. , Chason E. , Picraux S. T. , Brice D. K. , Horn K. M. 
Published: March 2011

ABSTRACTLow energy Ar and Xe ion bombardment of Ge (001) produces large numbers of point defects on the Ge surface and in the near-surface regions. Defect concentrations on the surface are detected and quantified in real time during bombardment using in situ Reflection High Energy Electron Diffraction (RHEED). We report the energy dependence of the defect yield for 70–500 eV Ar and Xe ion bombardment, and the temperature dependence of the defect yield (defects/ion) during 200 eV ion bombardment. The defect yield drops rapidly as the substrate temperature during bombardment is varied from 175 K to 400 K. We attribute the yield reduction to surface recombination of adatoms and vacancies produced in the same collision cascade.
Parameter Extraction from the Reverse I-V and C-V Characteristics of an Epitaxial p-InP/Au Schottky Diode
Authors: Singh A. , Cova P. , Masut R. A. 
Published: March 2011

ABSTRACTEpitaxial p-InP/Au Schottky diodes were fabricated by evaporation of Au onto Zn doped epitaxial layers of InP grown by MOVPE, on a highly doped InP substrate. The reverse current-voltage (Ir-Vr) and 1 MHz capacitance-voltage (C-V) characteristics of the Au/p-InP diodes were measured in the temperature range 220-393 K. At all temperatures, soft reverse current-voltage characteristics were observed, which may be due to the decrease in the effective Schottky barrier height (øbr) with the increase of Vr. The voltage dependence of the reverse current was well described in terms of the interface layer thermionic emission (ITE) model which incorporates the effects of applied reverse voltage drop and the transmission coefficient across the interface layer and image force lowering of the barrier height into the thermionic emission theory. A self consistent iteration and least square fitting technique was used to obtain the zero bias barrier height (øbo) and interface layer capacitance (Ci) from the Ir-Vr data. Both, the Ir-Vr and the C-V data were analyzed under the assumption of reverse bias voltage independence of the charge trapped in the interface states, which was supported by our experimental data. The values of øbo obtained from the C-V measurements agreed well with those obtained from the Ir-Vr data for a value of 0.45 AK−2cm−2 for the effective Richardson constant (Aeff).
The Interface for Cryogenic-Processed Metal/Inp
Authors: He L. , Anderson W.A. , Palmer J. , Shi Z. 
Published: March 2011

ABSTRACTAu and Pd Schottky contacts to n-InP produce extremely high barrier heights and low leakage currents when deposition is on a substrate cooled to 77K. Extensive chemical and structural analyses indicate that this process causes the metal film to be continuous at 50Å, much better than in standard processing. Stoichiometry of InP near the surface is better maintained with this process. A thin P:O compound may exist at the interface which also contributes to a high barrier height.
Changing PL Intensity from GaAs/Al0.3Ga0.7As Heterostructures due to the Chemisorption of SO2: Effects of Heterostructure Geometry
Authors: Geisz J.F. , Kuech T.F. , Ellis A.B. 
Published: March 2011

ABSTRACTChemical adsorption of gases onto semiconductor surfaces results in a change in the density of electronic surface states. The corresponding change in the number of surface charges gives rise to a measurable change in the bulk charge distribution within the semiconductor. This phenomenon forms the basis of a novel solid-state chemical sensor device using the intensity of photoluminescence (PL) as a measurement technique. We have observed changes in the PL intensity from MOVPE-grown GaAs/Al0 3Ga0 7As heterostructures due to the chemisorption of SO2 onto “photowashed” GaAs surfaces. The photowashing technique is believed to reduce the density of preexisting surface states by removing As from the GaAs surface oxide. The PL signal-to-noise ratio and PL sensitivity characteristics of these chemical sensors may be dramatically improved by varying semiconductor structure. We have observed a range of PL enhancements upon exposure to 0.6% SO2 in flowing N2 from heterostructure layers with various thicknesses and doping densities. These results are explained by comparison with a FEM numerical model derived to correlate the relative PL intensity from various heterostructures to the surface charge density.
Improved Adhesion of P-doped SiO2-Interface Layers on InP by Low-Temperature Damage-Free Plasma-CVD
Authors: Riemenschneider R. , Hartnagel H.L. , Kräutle H. 
Published: March 2011

ABSTRACTThe deposition of thin films on III-V compound semiconductors is encountered with various interfacial problems. We present a new approach using a modified plasma technique in a phosphorous ambient at substrate temperatures ranging from 250 to 350 °C which covers two import aspects: Firstly, a good insulator quality due to the plasma process. Secondly, an appropriate surface pre-treatment and defect passivation by a phosphine-like cleaning process using a solid phosphorous source. The analysis of the film adhesion yields improved adhesive properties due to the high activation energy of a plasma process for surface reactions, and by preventing a phosphorus-related defects. The phosphorous concentration in the SiO2 films has to be adapted in order to prevent electrical degradation of the SiO2-InP interface. The influence of phosphorous deficiency and excess phosphorous will be discussed.
Thermally Driven In-Situ Removal of Native Oxide Using Anhydrous Hydrogen Fluoride
Authors: Apte Pushkar P. , Park Heungsoo , Saraswat Krishna C. , Helms C. R. 
Published: March 2011

ABSTRACTIn-situ native-oxide removal is critical for epitaxial single-crystal silicon deposition, for polysilicon emitters and contacts and for ultrathin gate dielectric films in integrated circuit (IC) fabrication. We have developed an in-situ, thermally-driven, anhydrous hydrogen fluoride (AHF)-based native-oxide removal technique in which the wafer is treated by AHF at low temperatures (300-400°C) and a short (10 sec) 950°C ‘spike’ in AHF-H2 immediately prior to Si deposition. This process removes native oxides formed by standard wet cleans such as HC1:H202 and NH4OH:H202, as well as native oxides formed by the clean-room ambient. Further, the technique is an effective pre-clean for both polysilicon and epitaxial silicon deposition. This flexibility, combined with other salient features such as simplicity and a low thermal budget, make the process eminently suited for IC fabrication.
Chemical Modification of Surface Steps on SI(111) Vicinal Wafers: a Bonding Model for Phase Changes in Second Harmonic Generation
Authors: Jing Z. , Lucovsky G. , Whitten J. L. 
Published: March 2011

ABSTRACTThere have been several studies of second harmonic generation (SHG) from chemically-modified vicinal Si(111) wafers. The SH fields contain one-fold (ψ) and three-fold (3ψ) symmetry contributions, which originate respectively from the terrace and surface step atoms. The phase of these contributions are different for native oxides, and are a function of the frequency of the incident radiation, ω. To identify the origin of these different phases for the terrace and step SH fields, we use a classical anharmonic oscillator model based on two assumptions: (a) a significant fraction of Si atoms at the steps have dangling bonds when oxides are formed below ∼850°C, and (b) these step atoms are linked to atoms at the bottom of the steps by O-Si-O groups following annealing at >900°C.