bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flux Dependence of Amorphous Layer Formation and Damage Annealing in Room Temperature Implantation of Boron into Silicon
Authors: Simonton Robert , Shi Jinghong , Boden Ted , Maillot Philippe , Larson Larry 
Published: March 2011

ABSTRACTWe implanted <100> silicon 200mm wafers with 20keV 11B+ to a fluence of 5×1015 atoms/ cm2 using beam currents from 1-7mA, which produced flux of about 50-350µA/cm2. The implant temperature of all wafers rose no more than five degrees above room temperature, regardless of flux. Cross sectional TEM images (as-implanted) of the highest flux samples revealed a continuous amorphous layer from the implanted surface to a depth of about 530Å. The high flux and <30°C implantation temperature allowed amorphous layer formation even with this moderate boron fluence, as was suggested by Jones, et.al.1. We observed a strong dependence of as-implanted damage on boron flux, as previously reported by Eisen and Welch2. After 900°C, 20 sec RTA, the highest flux samples had 50% lower sheet resistance than the lowest flux samples, due to better activation, as observed in SRP. When a 1050°C, 15 sec RTA was employed, this sheet resistance and activation dependence on flux disappeared. Cross sectional TEM images revealed that the size and number of the Type II end of range defects , which were centered near the amorphous and crystalline as-implanted interface, in the highest flux samples were smaller than the Type 1 dislocation loops centered about the peak disorder in the lowest flux samples after RTA. SIMS and SRP profiles indicated that transient enhanced diffusion during the 900°C, 20 sec RTA may have been reduced in the highest flux samples. Based on these observations and on previous reports, we conclude that sufficiently high flux during room temperature boron implantation will produce a continuous amorphous layer with doses that are appropriate for p-type source/drain formation. The amorphous layer will produce improved activation and damage annealing behavior in subsequent RTA, particularly as the RTA temperature is reduced.
Defect Induced Amortization in Silicon: A Tight Binding Molecular Dynamics Simulation
Authors: Maric D. , Colombo L. 
Published: March 2011

ABSTRACTWe present an investigation on the amorphization process of crystalline silicon induced by ion beam bombardment by simulating the insertion of self-interstitials at different temperatures. The simulation is carried out by tight-binding molecular dynamics which allows for a detailed characterization of the chemical bonding and electronic properties of the irradiated samples. The irradiation process consists of two steps: (i) insertion of defects at a constant rate; (ii) annealing of the sample and observation of its structural properties. Thanks to the large size of the simulation cell (up to 276 atoms) we can characterize the amorphous network both on the short-range and medium-range length scale. Electronic properties are investigated as well and their evolution is monitored during the insertion process. Finally, we present a thorough comparison of the structural properties of the irradiated sample with amorphous silicon as obtained by rapid quench from the melt.
Amorphization and Dynamic Recovery of A2BO4 Structure Types During 1.5 MeV Krypton Ion-Beam Irradiation
Authors: Wang L.M. , Gong W.L. , Ewing R.C. 
Published: March 2011

ABSTRACTThe temperature dependence of the critical amorphization dose, Dc of four A2BO4 compositions, forsterite (Mg2SiO4), fayalite (Fe2SiO4), synthetic Mg2GeO4, and phenakite (Be2SiO4) was investigated by in situ TEM during 1.5 MeV Kr+ ion beam irradiation at temperatures between 15 to 700 K. For the Mg- and Fe-compositions, the A-site is in octahedral coordination, and the structure is a derivative hcp (Pbnm); for the Be-composition, the A- and B-sites are in tetrahedral coordination, forming corner-sharing hexagonal rings (R3). Although the Dc's were quite close at 15 K for all the four compositions (0.2–0.5 dpa), Dc increased with increasing irradiation temperature at different rates. The Dc-temperature curve is the result of competition between amorphization and dynamic recovery processes. The Dc rate of increase (highest to lowest) is: Be2SiO4, Mg2SiO4, Mg2GeO4, Fe2SiO4. At room temperature, Be2SiO4 amorphized at 1.55 dpa; Fe2SiO4, at only 0.22 dpa. Based on the Dc-temperature curves, the activation energy, Ea, of the dynamic recovery process and the critical temperature, Tc, above which complete amorphization does not occur are: 0.029, 0.047, 0.055 and 0.079 eV and 390, 550, 650 and 995 K for Be2SiO4, Mg2SiO4, Mg2GeO4 and Fe2SiO4, respectively. These results are explained in terms of the materials properties (e.g., bonding and thermodynamic stability) and cascade size which is a function of the density of the phases. Finally, we note the importance of increased amorphization cross-section, as a function of temperature (e.g., the low rate of increase of Dc with temperature for Fe2SiO4).
A Cubic Phase Formed in Immiscible Fe/Ag(Cu) System S by Ion Mixing
Authors: Liu B.X. , Pan F. , Tao K. 
Published: March 2011

ABSTRACTFexAg1-x (x=0.20-0.65) and Fey Cu1-y (y=0.50-0.75) nano-multilayers were prepared by alternative deposition of pure constituent metals. Ion mixing of the multilayers by 200 keV xenon ions at 77K resulted in the formation of a similar metastable phase with a big lattice of cubic structure, when the ion dose exceeded 1×1016 and 1×1015 Xe+/cm2 for Fe/Ag and Fe/Cu systems, respectively. The fraction of the new phase emerged in the alloy films increased with increasing ion dose in both cases.
Piezoresistivity in Ion Implanted Polymer Films
Authors: Wang Y.Q. , Robey D.S. , Giedd R.E. , Moss M.G. 
Published: March 2011

ABSTRACTPiezorcsistive properties have important sensor applications. In this study we find that several ion implanted polymers exhibit piezorcsistive properties. Piezoresistive gauge factors of these films are found to be significantly greater than those of metals, however smaller than those of semiconductors. Potential advantages of using the piezorcsistive properties of these films are also discussed.
Ion Beam Synthesis of Luminescent SI and GE Nanocrystals in a Silicon Dioxide Matrix
Authors: Atwater H.A. , Shcheglov K.V. , Wong S.S. , Vahala K.J. , Flagan R.C. , Brongersma M.L. , Polman A. 
Published: March 2011

ABSTRACTIon beam synthesis of Si and Ge nanocrystals in an SiO2 matrix is performed by precipitation from supersaturated solid solutions created by ion implantation. Films of SiO2 on (100) Si substrates are implanted with Si and Ge at doses 1 × 1016/cm2 - 5 × 1016/cm2. Implanted samples are subsequently annealed to induce precipitation of Si and Ge nanocrystals. Raman spectroscopy and high-resolution transmission electron microscopy indicate a correlation between visible room-temperature photoluminescence and the formation of diamond cubic nanocrystals approximately 2–5 nm in diameter in annealed samples. As-implanted but unannealed samples do not exhibit luminescence. Rutherford backscattering spectra indicate a steepening of implanted Ge profiles upon annealing. Photoluminescence spectra are correlated with annealing temperatures, and compared with theoretical predictions for various possible luminescence mechanisms, such as radiative recombination of quantum-confined excitons, as well as possible localized state luminescence related to structural defects in SiO2. Potential optoelectronic device applications are also discussed.
Accumulation of Implantation Damage in MEV Implanted Diamond Crystals
Authors: Hunn John D. , Withrow S.P. , Clausing R.E. , Heatherly L. , Bentley J. , Hembree D.M. , Parikh N.R. 
Published: March 2011

ABSTRACTSingle crystal, type IIa natural diamond substrates have been implanted with 4 MeV carbon ions to doses ranging from 0.5–130×1016 cm-2. The accumulation of implantation damage is studied by Raman and RBS/channeling. Similar effects are observed for crystals of [100], [110], and [111] orientation but with different rates of damage accumulation. With increasing implantation damage, the triply degenerate Raman mode at 1332 cm-1 broadens and shifts down to around 1300 cm-1. This corresponds to a peak in the one-phonon density of states as predicted for Raman from an amorphous sp3 network. There is no evidence for the existence of sp2 carbon in the implanted area. Additional non-graphite Raman peaks appear at 1451, 1494, and 1635 cm-1. At the higher doses, the 1332 cm-1 Raman mode is no longer observed; however, RBS/channeling still shows the surface region to be crystalline and it is possible to grow high quality homoepitaxial diamond films on these substrates.
Characterization of Thermally Annealed Sb Implanted Fused Silica
Authors: Morgan S.H. , Pan Z. , Henderson D.O. , Park S.Y. , Weeks R.A. , Magruder R.H. , Zuhr R.A. 
Published: March 2011

ABSTRACTThe local environment of the polarizable ion in heavy metal oxide glasses is postulated to strongly influence the nonlinear response of these materials. We have previously observed that post-implantation thermal annealing changes the chemical properties of the implanted layer in a different fashion in Pb- and Bi- implanted SiO2. In this paper we report the optical behavior of Sb-implanted SiO2 as a function of annealing temperature and atmosphere. High purity fused silica substrates were implanted at room temperature to a dose of 6 × 1016 ions/cm2, and subsequently annealed at temperatures from 500 to 1000 C in argon and oxygen atmospheres. RBS, optical absorption (1.8 to 6.2 eV), infrared reflectance (450 to 5000 cm-1), and nonlinear index of refraction were measured before and after annealing. The results of these measurements indicate that annealing treatment significantly affects the local environment of the implanted Sb ions, and consequently the optical response.
Colloidal Au Nanoclusters Formed in Fused Silica by MeV Ion Implantation and Annealing
Authors: White C. W. , Zhou D. S. , Budai J. D. , Zuhr R. A. , Magruder R. H. , Osborne D. H. 
Published: March 2011

ABSTRACTMeV implantation of Au has been used to create a high density of Au nanoclusters in the near surface of fused silica. Measurements of the nanocluster size and size distribution under various implantation/annealing conditions are presented and correlated with measurements of optical absorption arising from surface plasmon resonance absorption by the Au nanoclusters in fused silica. Preliminary measurements of the nonlinear refractive index are included.
Application of Coatings for Electromagnetic Gun Technology
Authors: Otooni M. A. , Graf A. , Colombo G. , Conrad J. , Sridharan K. , Shamim M. M. , Fetherston R. P. , Chen A. 
Published: March 2011

ABSTRACTCopper and aluminum are extensively used in various parts of the Electromagnetic (EM) Gun systems. Copper is used in the design of the railgun because it has favorable electrical and thermal properties. Aluminum is used for armature and sabot fabrication because of it is light weight and has favorable thermal properties. Extensive degradation of the copper rail and aluminum armature occurs owing to the severe heating and thermomechanical deformation of these components during operation of the EM gun. In this research effort, several modification techniques were used to protect the rail and armature materials from these degradation processes. These include application of Plasma Source Ion Implantation (PSII) and Ion Beam Enhanced Deposition (IBED) . By using these techniques, the copper rails and aluminum armatures were coated with TiN and TaN. Several characterization techniques were used to assess the chemical,mechanical and other properties of these modified surfaces. Optical Microscopy, Scanning and Transmission Electron Microscopy, and Scanning Auger Spectroscopy techniques were also used. Microhardness measurements have also been performed. From the results of this preliminary investigation, it has been concluded that the surface properties of the coated rail and armature materials have been improved and the extent of wear and spark erosion from these surfaces has been reduced.
Improvement of Strength and Reliability of Structural Ceramic through Ion Implantations
Authors: Bhattacharya Rabi S. , Rai A.K. 
Published: March 2011

ABSTRACTThe feasibility of strength and reliability improvements of Si3N4 through ion implantations has been studied. The approach has been to implant elements that may chemically combine with themselves to form precipitates after appropriate annealing. These precipitates can improve the strength and reliability of ceramics through the introduction of a compressive stress in the implanted surface layer and/or by modifying the fracture originating machining flaws. Sequential implantations of ion pairs of Ti+ and C+, and Si+ and C+ were performed at energies in the range 46 to 175 keV and at doses of 1×1017 cm-2 for each ion species. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM) techniques were used to analyze the implanted layer. Strength and reliability were determined from four-point flexure strength measurements. Precipitates of TiN and C were found to form in Ti++C+ and Si++C+ implanted Si3N4 surfaces, respectively. Si++C+ implantation resulted in improvements of both strength and reliability of Si3N4, while Ti++C+ implantations had no effect.
Structural Characters and Tribological Properties of Diamondlike Carbon Films
Authors: He Xiao-Ming , Li Wen-Zhi , Li Heng-De 
Published: March 2011

ABSTRACTDiamond-like carbon films have been prepared by using dual ion beam sputtering deposition under CH++Ne+ bombardment with energies 50–800 eV. The obtained films possess a smooth surface and an amorphous structure containing some sp3 bondings. DLC films bombarded by low energy CH++Ne+ exhibit the relatively high binding energy and electrical resistivity which are approximate to those of diamond. It is believed that a Mo interlayer between AISI 52100 steel substrates and DLC films brings the films good adhesion. This offers promises to DLC films on bearing steel to perform a stable wearing in much lower friction coefficient (<0.1) under large wear loads (30–90N). Experimentally, low wear coefficients and high anti wear numbers obtained prove that the DLC films indeed possess excellent wear resistance. In addition, the speed or the momentum of friction motion was revealed to exert some serious effects upon the wear resistance of DLC films when the wearing was carried out under very high wear load (> 30 N).
Electric Field Induced De-channeling in LiNbO3
Authors: Zimmerman R. L. , Ila D. , Kukhtarev N. , Williams E. K. 
Published: March 2011

ABSTRACTAn electric field has been imposed on single crystals of pure and doped LiNbO3 during bombardment with 1.03 MeV protons and 2.1 MeV alpha particles. Simultaneous (p,p), (p,α) and (p,p'γ) channeling between the crystal planes showed that the channeling is less pronounced when an electric field of 106 volts/m is imposed perpendicular to the incident ion beam direction and to the channeling planes in the crystal. The results obtained are discussed and compared to the effects due to the fringe field outside the crystal, differential cation-anion movement, movement of interplanar impurities, the piezoelectric strain and movement or creation of crystal defects on ion channeling.
Simox Material Development for Sub-0.25µm Cmos Technology
Authors: Sadana D.K. , Hovel H.J. , Frecouf J.L. , Chu S.F. , Watson T.J. 
Published: March 2011

ABSTRACTAdvantages of SOI materials for CMOS technology arc discussed. The lending SOI materials for CMOS applications appear to be SIMOX and BSOl presently. Progress made in two types of SIMOX, namely, standard and thin BOX. is presented. Recent results from 200mm SIMOX are included. Finally, various defects in annealed SIMOX are discussed. An effort has been made to present data which is typical of commercial SIMOX.
Defect Pair Formation by Implantation-Induced Stresses in High-Dose Oxygen Implanted Silicon-on-Insulator Material
Authors: Lee J.D. , Park J.C. , Venables D. , Krause S.J. , Roitman P. 
Published: March 2011

ABSTRACTDefect microstructure and the near-surface strain of high-dose oxygen implanted silicon-on-insulator material (SIMOX) were investigated as a function of dose, implant temperature, and annealing temperature by transmission electron microscopy and high resolution x-ray diffraction. Dislocation half loops (DHLs) begin to form by stress assisted climb at a critical stress level due to implantation-induced damage. DHLs evolve into through-thickness defect (TTD) pairs by expansion during annealing. Both DHL and TTD-pair density increase with higher implant dose and lower implant temperature. Possible methods for defect density reduction are suggested based on the results of this study.
Characterization of GeSi Layer Formed by High Dose Ge Implantation into Si
Authors: Cheung W.Y. , Wong S.P. , Wilson I.H. , Zhang T.H. 
Published: March 2011

ABSTRACTHigh dose Ge implantation into p-type <100> Si wafers at 150 keV has been performed at doses of 3.6×1016, 6.7×1016 and 9.0×1016 cm-2. The Ge distribution and the crystal quality of the implanted layer before and after annealing at various temperatures have been studied by RBS and channelling experiments. It is found that for the medium and high dose samples before annealing, more than 90% of the Ge atoms are in interstitial sites and after annealing at 1000°C, more than 50% of the Ge atoms have become substitutional. The situation is better for the low dose sample where less than 70% of the Ge atoms are in interstitial sites before annealing and about 80% of them become substitutional after annealing at 1000°C. The ESR spectra of these samples are of lorentzian shape with a g-value of about 2.007 and a spin density of about 6×1016 cm-3. The ESR signals of these samples have been inferred to be mainly due to Si-dangling bonds in the GeSi alloy layer and can be eliminated by annealing at 1000°C for 10 minutes. Electrical characterization of the GeSi layer by spreading resistance profiling technique shows that the implantation damage has been extended deep into the substrate before annealing. After annealing at 1000°C, these defects are removed but the spreading resistance of the surface GeSi layer is found to remain higher than that of the substrate.
Growth Rate of Solder Intermetallics
Authors: Demaree J. D. 
Published: March 2011

ABSTRACTThe formation of intermetallic layers between copper wires and lead-tin solders is indicative of the strong metallurgical bond required for a durable solder joint Previous studies have shown that these interracial compounds grow at significant rates (up to 1 µm/day at 100°C), and differences in thermal expansion and hardness between the metals and the intermetallics can lead to the mechanical failure of the solder joint during service. Most previous measurements of the compound formation rate have used elevated temperatures to facilitate the direct observation of the intermetallic thickness by optical microscopy, SEM, or TEM. In this study, Rutherford backscattering spectrometry (RBS) has been used to study the intermetallic growth rate using sputter-deposited thin films of Cu and PbSn. The extraordinary depth sensitivity of RBS (~10 nm) allows these measurements to be made in relatively short times, without the need for heat treatment to accelerate the reaction. Measurements have indicated that at least 23 nm of Cu6Sn5 and 30 nm of Cu3Sn form between Cu and PbSn solder in less than one hour. Faster deposition methods are being investigated to further characterize this rapid reaction. Iron has been proposed as a diffusion barrier material to inhibit intermetallic growth in solder joints. Preliminary measurements of the solder/Fe reaction indicates a much slower rate of growth, with less than 50 nm of total intermetallic forming over 8 hours.
Low Energy Ion Implantation / Deposition as a Film Synthesis and Bonding Tool
Authors: Anders André , Anders Simons , Brown Ian G. , Ivanov Igor C. 
Published: March 2011

ABSTRACTWe describe a novel means for the production of atomically-bonded thin films of a wide range of materials. The technique is a plasma and ion beam method involving synthesis of the desired surface film by plasma deposition and the simultaneous atomic mixing of the film into the substrate by low energy ion implantation from the surrounding plasma. Vacuum-arc-produced metal plasma is used for the metallic component of the film and gases can be added to form compound films. Multiple plasma generators can be used, and films of single metals, alloys, ceramics and multilayers can be formed. By repetitively pulse biasing the substrate during plasma deposition, the growing film is subjected to energetic ion bombardment, and direct and recoil ion implantation is induced. The depositing film is thereby atomically mixed to the substrate as it is formed. The films are atomically smooth, can be anywhere from a few monolayers to microns in thickness, and the interface or mixed transition zone can be tailored. Here we outline the basic plasma physics of the method and describe a number of novel surfaces which have been formed with excellent properties.
Element Profiles of Surface Layers Created by Metal Ion Beam Assisted Deposition
Authors: Duvanov Sergei M. , Kobzev Alexander P. , Tolopa Alexander M. 
Published: March 2011

ABSTRACTDepth profiles of elements in the surface layers of metals and metallized dielectrics were investigated by Rutherford Backscatteríng Spectrometry (RBS) (for the depth profiling of heavy elements), resonant elastic Backscattering Spectrometry (BS) of 4He+ and 1H+ (for the light elements depth profiling), Elastic Recoil Detection (ERD) of 1H+ (for depth profiling of hydrogen atoms), SIMS and AES techniques. The technological TAMEK source operated in the regime of ion beam assisted deposition (IBAD) of the metal ions (ion implantation at average beam energy ≤ 150 KeV and simultaneous deposition of the same ions at energy 100 eV) in pulse mode. Coatings were deposited on metal and glass samples at temperature of substrates T=100° C. In this report, we discuss the investigation results of samples modified by IBAD in technical vacuum produced by oil diffusion pumping. Phases like TiO, TiC, TiN, TiH are indicated in interface coating-substrate layers. The total thickness of mutually mixed metal-glass layer was found to be 400 nm and it was equal up to 3 µm for metal-metal layers. Cu/Al thin layers on a glass subsrate may be used as mirrors for powerful lasers with large (up to 5 J/cm2) energy contribution.
Epitaxial Planarization Using Ion Beam Assisted Deposition
Authors: Chang Bertha P. , Sonnenberg Neville , McIntyre Paul C. , Cima Michael J. , Sun Jonathan Z. , Yu-Jahnes Lock See 
Published: March 2011

ABSTRACTCeO2 thin films have been deposited on patterned (100) LaAlO3 substrates using ion beam assisted deposition (IBAD) with ion beam energies between 350 and 500eV. Deposition temperatures were varied between 400°C and 600°C and deposition rates from 0.2Å/s to 1.2Å/s. Both normal and off-normal incidence ion bombardment have been studied. A trend towards planarization is observed when the ion to atom ratio is adjusted to obtain the proper degree of etching. The planarization mechanism for normal incidence bombardment appears to be similar to that previously observed for bias sputtering. X-ray diffraction shows that an initial layer of evaporated epitaxial CeO2 is required for continued epitaxial development during IBAD processing. The extent of planarization via off-normal ion incidence can be related to the direction of the ion beam with respect to the patterned features. X-ray pole figure measurements show that these films possess an in-plane orientation that is directly related to the ion beam parameters.