bluuebunny/crossref_metadata_2025_split huggingface dataset:
Limited Reaction Processing: Growth of III-V Epitaxial Layers by Rapid Thermal Metalorganic Chemical Vapor Deposition
Authors: Reynolds S. , Vook D.W. , Gibbons J.F. 
Published: March 2011

ABSTRACTRapid thermal processing (RTP) has been applied to improve the versatility of metalorganic chemical vapor deposition (MOCVD). We have demonstrated a new pulsed growth method which yields enhanced layer thickness control and abrupt interfaces (2–4 atomic layers) while maintaining a high growth rate (10Å/sec). In this technique, substrate temperature is used as a switch to control the growth of epitaxial layers.
The unfocused tungsten halogen lamps used in RTP have also facilitated a novel thermal precracking technique, producing the best GaAs ever grown using trimethylarsenic (TMAs). Background doping is reduced by a factor of 5, and carbon incorporation is reduced by a factor of 10 or more. Net background doping below 1016 cm−3 and room temperature electron mobilities of 4000 to 4500 cm2/V. sec have been obtained.
Point Defect Evolution During Rapid Thermal Annealing of Si+-Implanted GaAs.
Authors: Levinson M. , Armiento C. A. , Shah S. S. P. 
Published: March 2011

ABSTRACTThe point defect reactions in GaAs by which ion implant damage is removed and implanted dopants are activated remain poorly understood. Deep level capacitance transient spectroscopy (DLTS) has been used to study the effects of rapid thermal annealing (RTA) on Si-implant damage generated defects. In low implant dose samples, the results of RTA are similar to those of furnace anneals and also agree well with previous reports of boron-implanted and neutron-irradiated material. In contrast to this, higher dose samples showed much smaller than expected apparent defect concentrations. After RTA, very broad DLTS spectra and relatively little EL2 or EL3 defect formation was observed. The significance of these results with regard to the mechanisms of dopant activation and damage removal are discussed.
Rapid-Thermal-Processing Induced Deep Level Traps and their Spatial Distribution in MBE GaAs
Authors: Kitagawa Akio , Tokuda Yutaka , Usami Akira , Wada Takao , kano Hiroyuki 
Published: March 2011

ABSTRACTRapid thermal processing (RTP) using halogen lamps for a Si-doped molecular beam epitaxial (MBE) n-GaAs layers was investigated by deep level transient spectroscopy. RTP was performed at 700°C, 800°C and 900°C for 6 s. Two electron traps NI ( Ec-0.5-0.7eV) and EL2 (Ec - 0.82 eV) are produced by RTP at 800 and 900°C.The peculiar spatial variations of the Nl and EL2 concentration across the MBE GaAs films are observed. The larger concentrations of the trap N1 and EL2 are observed near the edge of the samples, and the minima of N1 and EL2 concentration lie between the center and the edge of the sample. It seems that these spatial variations of N1 and EL2 concentration are consistent with that of the thermal stress induced by RTP. Furthermore, the EL2 concentration near the edge of the sample is suppressed by the contact with the GaAs pieces on the edge around the sample during RTP.
Formation of p+ and High Resistivity Regions in GaAs-AIGaAs Heterojunctions
Authors: Pearton S. J. , Brown J. M. , Short K. T. 
Published: March 2011

ABSTRACTThe formation of p+ and high resistivity layers in GaAs-AIGaAs heterostructures is useful in a number of applications, including the fabrication of heterojunction bipolar transistors (HBTs). Control of the implanted dopant profile during annealing is paramount for rapidly diffusing acceptor species such as Be and Mg, and we show SIMS data of the dopant profile in implanted heterojunctions as a function of annealing temperature in the range 700–900°C for 1–5 sec. Annealing of implanted Be at ≥800°C even at a dose of 2×10l5cm−2 results in complete activation whereas Mg shows only 30% activation under these conditions. There is no significant interface disordering visible by TEM or RBS for either case. Multiple energy O implants (up to and including 1 MeV) were used to render the entire heterostructure resistive; for doses of ∼1013cm−2, the O bombarded layers showed resistivities of 108 Ω/□ after 525°C annealing.
Raman Scattering Study of the Au-Ge-Gaas Ohmic Contact Structure Formed by Rapid Thermal Processing
Authors: Kirillov D. , Chung Y. 
Published: March 2011

ABSTRACTRaman Scattering Was Used To Obtain New Information on the formation of Au-Ge-GaAs alloyed ohmic contacts. During alloying, we observe that amorphous Ge is transfoplmed into polycrystalline material. When Ge diffuses into the GaAs, no n+-GaAs layer is formed. Due to the intermixing of layers, both GaAs and Ge had a large number of impurities which formed deep electronic states in the forbidden gap. Electronic light scattering involving these states was observed. While several models for the Au-Ge-GaAs ohmic contact have been proposed, the model consistent with our Raman data includes resonant tunneling assisted by impurity levels in the graded Au-Ge-GaAs heterojunction structure as a basic conduction mechanism.
Rapid Thermal Diffusion of Zinc In GaAs
Authors: Kalkur T.S. , Lu Y.C. , Paz de Araujo C.A. 
Published: March 2011

ABSTRACTRapid thermal diffusion of zinc into semi-insulating GaAs from spin-on zinc silica film is investigated. The rapid thermal diffusion is performed for various diffusion times (5 to 25 sec) and temperatures (800° to 950° C) with tungstenhalogen lamps as the heat source. The sheet resistivity, surface hole concentration and mobility of these zinc diffused layers as measured by Van der Pauw technique shows the formation of shallow p+ layer. The surface morphology of these diffused layers are observed in a low voltage Scanning Electron Microscope (SEM) and the depth profile of diffused impurities are determined by Secondary Ion Mass Spectroscopy (SIMS). Nonalloyed ohmic contacts are formed on these zinc diffused layers and the contact resistivity is determined by the Transmission Line Method (TLM).
Rapid Thermal/Plasma Processing for In-Situ Dielectric Engineering (Invited)
Authors: Moslehi Mehrdad M. 
Published: March 2011

ABSTRACTRapid thermal processing of silicon in oxygen and ammonia ambients is an attractive technique for the growth of thin dielectrics such as silicon nitride, silicon dioxide, nitrided oxides, oxidized nitrides, and application-specific (composition-tailored) insulators. Multicycle rapid thermal growth processes are suitable for dielectric engineering and in-situformation of thin layered insulators with a variety of controllable oxygen and nitrogen compositional depth profiles by appropriate design of the temperature and ambient gas cycles. The growth and electrical properties of various dielectrics rapidly grown by the state-of-the-art techniques and their corresponding device performance are examined. Rapid thermal processing and microwave plasma generation have been combined in a novel custom-made multipurpose reactor for rapid plasma-enhanced multiprocessing of Si, Ge, and GaAs. Thin germanium nitride dielectrics can be formed by rapid thermal or plasma nitridation for germanium CMOS applications. Combination of in-situ rapid plasma nitridation followed by silicon nitride deposition may prove to be effective for MIS structures and surface passivation on GaAs. These new applications of rapid thermal/plasma processing are additional steps towards realization of fully RTP-based Si VLSI fabrication processes and development of new devices and technologies on other semiconductor materials.
Process and Equipment Issues in Rapid Thermal Oxidation (RTO)
Authors: Sandeep Mehta Sandeep Mehta , David Hodul David Hodul 
Published: March 2011

ABSTRACTThin oxides with thicknesses in the range of 150 to 300Å were grown on lOO-mm <100> Si wafers in a commercial RTP reactor. Growth temperatures and times were llO0-1200°C for 60-180 seconds in 100% 02 at 1 atmosphere. Oxide thickness uniformity was measured using ellipsometry; contour maps of thickness uniformity will be presented. The standard deviation wascalculated to be 2-2.5% within 5 mm of the edge using a method which weights the area represented by each of 45 data points per wafer. In order to correct for dynamic changes in temperature uniformity, a new annealing method was developed.Results on wafer-to-wafer uniformity will be presented. Improvements achieved by post-oxidation annealing in N2 and electrical uniformity of films will be discussed.
Characterization of Buried-Nitride Silicon for Integrated Circuit Applications
Authors: Myers D. R. , Stein H. J. , Tsao S. S. , Arnold G. W. , Hughes R. C. , Miller W. M. , Jones R. V. , Datye A. K. 
Published: March 2011

ABSTRACTWe have examined the microstructure and the transport properties of nitrogen-implanted silicon-on-insulator wafers, as well as the performance of integrated-circuit transistors fabricated in this material. The insulating regions were fabricated in silicon by the unpatterned implantation of 4×1017/cm2, 300 keV nitrogen dimers followed by annealing at 1473 K for 5 hours. For these parameters, the buried nitrogen-implanted layer crystallized into α-silicon nitride, and contains ≈20% excess silicon in the form of silicon inclusions of 5–15 nm diameter. The surface silicon layers are characterized by low-mobility, p-type conduction. The buried dielectric has a resistivity of approximately 108Ωcm. Functional p-channel, integrated circuit transistors have been fabricated in n-type epitaxial silicon grown over the buried-nitride wafers. These transistors devices are similar in performance to those fabricated in bulk silicon,(hole mobilities in inversion layers of 140 cm2/V-s), and demonstrate the suitability of the buried nitride process for integrated circuit applications.
Formation of Silicon-On-Insulator Structures by Multiple Oxygen Implantations
Authors: Bunker S. N. , Sioshansi P. , Tobin S. P. 
Published: March 2011

ABSTRACTHigh dose oxygen ion implantation into silicon is an established method to form buried insulating layers. The material produced by standard processing techniques typically exhibits buried layers which are a few hundred nanome ers thick with a threading dislocation defect density on the order of 108/cm2. Unusual structures can be obtained by using repetitive cycles of partial doses of ions followed by annealing and possibly epitaxial growth. Both low and high doses may be used, the former intended to provide decreased defect density and the latter to increase the thickness of the buried layer above the theoretical maximum for higher voltage isolation. The material properties resulting from several variations of this technique are described and characterized.
Temperature Dependence of Implantation Damage in Strained-Layer Superlattices
Authors: Myers D. R. , Arnold G. W. , Dawson L. R. , Biefeld R. M. , Hills C. R. , Doyle B. L. 
Published: March 2011

ABSTRACTWe have characterized damage production in both (InGa)As/GaAs and Ga(AsP)/GaP strained-layer superlattices for silicon implants at 80 K, 300 K or 673 K at fluences sufficient to induce compositional disordering of the superlattice layers. Implants at low temperatures (80 K for the (InGa)As/GaAs system, 300 K and below in the Ca(AsP)/GaP system) are characterized by well-defined amorphous layers at depths consistent with the predictions of ion range codes. Implants at higher temperatures are characterized by greatly reduced damage levels with substantial densities of extended defects located near the mean ion range. Point defect clusters are preferentially located in the ternary layers in the (InGa)As/GaAs SLS at the deepest part of the implanted zone. Despite the absence of amorphous layer formation, precipitous stress relief still occurs for the Si-implanted (InGa)As/GaAs SLS.
Ion Mixing of Ti/C and Fe/C Bilayers
Authors: Nastasi M. , Tesmer J. R. , Hirvonen J.-P. 
Published: March 2011

ABSTRACTBilayer samples of Ti/C and Fe/C have been ion beam mixed with 400 keV Xe ions to a dose of 1 × 1016 ions/cm2. Mixing experiments were performed at 77, 300, 573, and 723 K. The transition between the temperature independent and temperature dependent mixing occurred between 300 and 573 K in Fe/C samples and between 573 and 723 in Ti/C sample. In the temperature independent mixing regime mixing is reasonably well explained by a thermodynamic model of ion mixing while at higher temperatures a radiation enhanced diffusion mechanism is evident.
Direct Formation of Thin Films and Epitaxial Overlayers at low Temperatures Using a Low-Energy (10–;500 ev) Ion Beam Deposition System
Authors: Zuhr R. A. , Alton G. D. , Appleton B. R. , Herbot N. , Noggle T. S. , Pennycook S. J. 
Published: March 2011

ABSTRACTA low-energy ion beam deposition system has been developed at Oak Ridge National Laboratory and has been applied successfully to the growth of epitaxial films at low temperatures for a number of different elements. The deposition system utilizes the ion source and optics of a commercial ion implantation accelerator. The 35 keV mass- and energy-analyzed ion beam from the accelerator is decelerated in a four-element electrostatic lens assembly to energies between 10 and 500 eV for direct deposition onto a target under UHV conditions. Current densities on the order of 10 A/cm are achieved with good uniformity over a 1.4 cm diameter spot. The completed films are characterized by Rutherford backscattering, ion channeling, cross-section transmission electron microscopy, and x-ray diffraction. The effects of substrate temperature, ion energy, and substrate cleaning have been studied. Epitaxial overlayers which show good minimum yields by ion channeling (3–4%) have been produced at temperatures as low as 375°C for Si on Si(100) and 250°C for Ge on Ge(100) at growth rates that exceed the solid-phase epitaxy rates at these temperatures by more than an order of magnitude.
Ionized Cluster Beam Epitaxy of Single Crystal Metal Films on Semiconductors and Insulators
Authors: Yamada I. , Levenson L. L. , Usui H. , Takagi T. 
Published: March 2011

ABSTRACTOur experiments show that ionized cluster beams (ICB) can form epitaxial Al films on Si(111) and Si(100) substrates. This is unique because the lattice misfit of this material combination is more than 25%. Al can also be epitaxially grown on CaF2 films deposited on Si substrates. The initial stage of the film formation is measured by in-situ electron diffraction. In the case of Al(111) growth on Si(111) and CaF2, growth of mixed layers of different epitaxial islands of approximately 20–50 Angstrom thickness on the substrate surface is observed. With increase of thickness, the film shows the single crystal state with a flat surface, which indicates the epitaxial single crystal film formation on CaF2 or on Si substrates. It should be noted that in the Al/CaF2/Si (MIS) structure, the epitaxial CaF2 is a good insulating layer, which can be used to prepare three dimensional devices. These results show that the kinetic energy and the ionic charge of cluster ions have much influence on surface and interface modification, and that ICB is capable of producing films of good quality at low substrate temperatures.
Ion-Beam-Induced Modifications of Thin Films: Growth Simulations
Authors: Müller Karl-Heinz 
Published: March 2011

ABSTRACTIf the thermal adatom mobility is limited during film growth, the kinetic energy delivered to the film surface by arriving species is the key parameter which determines the resulting film microstructure and properties. Kinetic models and growth simulations of nonequilibrium film growth have been used to study the influence of incident kinetic energy of adatoms and energetic ions on the film microstructure, microporosity, density, stoichiometry and epitaxy. Deposition processes like vapor, sputter, ion-assisted and ionized cluster beam deposition, could be examined in detail with particular emphasis on optical coatings. The theoretical descriptions used are based on the solid-gas, thermal spike, collision cascade and molecular dynamics model.
Plasma-Activated CVD for the Production of Protective Layers in Optics, Electronics and Mechanical Engineering
Authors: Enke Knut , Geisler Michael , Kieser Jörg , Münz Wolf-Dieter 
Published: March 2011

ABSTRACTConventional chemical vapor deposition (CVD) has historically utilized high melting temperature substrates. Recently there has been an increased desire to coat temperaturesensitive materials such as aluminum, glass, steel, and even plastic. Thus “cold” CVDprocesses, most using plasma excitation, have been developed. In these processes gas molecules or atoms are excited by dc or ac glow discharge, thereby allowing the possibility of keeping substrates at room temperature.This paper describes plasma CVD reactors using capacitive coupling of r.f. voltage to an asymmetrical arrangement of electrodes. Using organic or metal-organic process gases and mixtures of them with inorganic gases, deposition takes place on the reactor walls, the anode, and the cathode. In this paper the emphasis is on deposition on negatively selfbiased substrate holders. Physical and chemical properties of plasma-CVD grown layers depend on about six process parameters, the most important of which are cathode voltage, gas pressure, choice of gases, and mixing ratio of gases. Map-like representations show the dependence of coating properties on deposition parameters. Layer materials discussed include amorphous hydrogenated carbon (a-C:H). WCx, SiOx:H, SiCxOy:H. and SnOx:H.
Wear of Ion Implanted Glassy Carbon
Authors: Pollock John T. A. , Farrelly Matthew , Wielunski Leszek S. 
Published: March 2011

ABSTRACTSignificantly improved wear properties are described for glassy carbon following implantation with 2 MeV helium and 50 keV nitrogen to doses in the range 1015–1017 ions cm−2. Implanted material is up to 100 times more wear resistant to diamond abrasion than unimplanted material. Enhanced wear resistance is available at the surface with nitrogen but lies below the surface with helium, reflecting the difference in modified depth associated with implant energy and ion mass. Unusually for ion implantation, dose related surface compaction is observed for both nitrogen and helium. Changes in microstructure during implantation with particular regard to collision processes and amorphisation of the graphitic fraction of glassy carbon are discussed.
Boron Nitride: Composition, Optical Properties, and Mechanical Behavior
Authors: Pouch John J. , Alterovitz Samuel A. , Miyoshi Kazuhisa , Warner Joseph O. 
Published: March 2011

ABSTRACTA low energy ion beam deposition technique was used to grow boron nitride films on quartz, germanium, silicon, gallium arsenide, and indium phosphide. The film structure was amorphous with evidence of a hexagonal phase. The peak boron concentration was 82 at %. The carbon and oxygen Impurities were in the 5 to 8 at % range. Boron-nitrogen and boron-boron bonds were revealed by x-ray photoelectron spectroscopy. The index of refraction varied from 1.65 to 1.67 for films deposited on the III–V compound semiconductors. The coefficient of friction for boron nitride in sliding contact with diamond was less than 0.1. The substrate was silicon.
Compared Nitrogen Implantations of Various Alloyed Steels
Authors: Moncoffre N. , Jaffrezic H. , Marest G. , Tousset J. , Zawislak F. C. , Faveulle S. , Brissot J. 
Published: March 2011

ABSTRACTNitrogen implantations in pure iron and various stE-els are investigated using nuclear reaction analysis, Conversion Electron M6ssbauer Spectroscopy and Grazing angle X-ray Diffraction. The present work sums up all the significant results although it does not constitue a systematic study. It describes the influence of the chemical composition and the structure effect of the matrix as well as those of the implantation time. The N-martensite, ε-nitride and ε-carbonitride phases are principally identified. The fraction of iron bound with nitrogen is evaluated in the different steels. The strong influence of the small chromium amounts inside the matrix upon the nitride formation is underlined. A preferential orientation of these phases is shown. SIMS experiments are presented in particular to determine the carbon distribution in the first surface layers.
Biological Tissue Adhesion to Ion Implanted Surfaces
Authors: Kelly J. C. , Evans M. D. M. , Wildish K. L. , Keirnan E. C. , Fisher L. R. , Howlett C. R. 
Published: March 2011

ABSTRACTResults of preliminary investigations on varying the adhesion and growth behaviour of osteoblast-like cells on silicon are presented. Significant changes in growth behaviour are obtained by implanting oxygen or by growing a thermal oxide on the surface. The objective of the work is to modify tissue adhesion to materials used as prosthetic devices.
Effect of Presputtering on the Adhesion of Cu to Teflon
Authors: Chang Chin-An , Lin K. C. , Baglin J. E. E. , Coleman G. , Park J. 
Published: March 2011

ABSTRACTAdhesion between Cu and Teflon has been greatly enhanced by a presputtering treatment of the Teflon prior to the deposition of Cu. Without such a treatment, the Cu-Teflon adhesion is weak, with a peel strength less than 1 gram/mm, and the Cu films can be easily peeled off using scotch tape. With the presputtering treatment, the adhesion rapidly increases, and reaches 50 grams/mm after 30 sec of sputtering. All the sputtered samples show strong adhesion, and the Cu films can only be scratched off forcefully using sharp tools. The presputtering treatment has changed the surface morphology of the Teflon and the deposited Cu layers, and also changes the chemical bonding between Cu and Teflon. The results are discussed to understand the mechanisms involved for the enhanced adhesion observed.
Surface Slip Retardation by ion Implantation
Authors: Samipath W. S. , Kustas F. M. , Wei R. , Wilbur P. J. 
Published: March 2011

ABSTRACTIon implantation is shown to retard surface slip and thereby induce improvements in wear and fatigue resistance of metals. A simple test is described which can be used to study the effects of ion implantation in retarding motion of dislocations in the near-surface regions of metals. In this test, regions of annealed and etched surfaces of metals are masked and implanted with ions. The specimens are then deformed until significant plastic deformation is introduced and the slip-lines are observed under the microscope. Evidence of improved resistance to slip-line formation in nitrogen ion implanted surface regions is presented for copper, α-iron and 303 stainless steel. The test is shown to be a useful tool for comparing the effects of ion implantation conditions on surface slip retardation, since adjacent regions of the surface can be implanted to different conditions and the resistance to slip line formation in the different regions can be compared. For example, the resistance to slip line formation in 303 stainless steel was found to be greater in regions that were implanted at ultrahigh current densities (1500 μA/cm2) than in regions implanted at lower current densities (100 μA/cm2) to the same dose and at the same ion energy.
Optical Reflectometry for Detailed Modeling of Buried Layers in Silicon-on-Insulator
Authors: Bunker S. N. , Sioshansi P. , Sanfacon M. M. , Tobin S. P. 
Published: March 2011

ABSTRACTOptical reflectometry has been used to describe the morphology of buried layers by high dose oxygen ion implantation into silicon. Previous work has demonstrated that the layer depth, thickness, and shape of surrounding regions with a graded concentration of oxygen can be successfully modeled when compared to SIMS and XTEM. A selection of nomographs for analyzing spectra resulting from conventional implant conditions as a function of dose and screen oxide thickness are presented.