bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transient Enhanced Diffusion in B+ and P+ Implanted Silicon
Authors: Pennycook S. J. , Culbertson R. J. 
Published: March 2011

AbstractWe report the transient enhanced diffusion of supersaturated phosphorus in ion-implanted SPE grown Si. Precipitation proceeds rapidly to a metastable SiP phase, which can be converted to an orthorhombic form or redissolved by subsequent heat treatment. The effects are strongly temperature dependent, and consistent with the trapped interstitial model. The behavior of different dopants follows their relative interstitialcy diffusion coefficients. The results suggest that ion implantation induced point defects dominate over thermally activated point defects during low temperature and certain rapid thermal processing, controlling dopant deactivation and diffusion in crystalline or amorphous silicon, and can also affect the SPE growth rate.
Simulation Studies of Collision Cascades in Liquid in Targets
Authors: Loi D. Y. , Shapiro M. H. , Tombrello T. A. , Garrison B. J. , Winograd N. 
Published: March 2011

AbstractMultiple interaction computer simulations have been used to determine the properties of collision cascades in liquid In targets induced by normally incident 5 keV Ar+ ions. Below the first atomic layer the cascade becomes Thompson-like relatively quickly. However, within the first atomic layer the angular distribution of moving atoms became forward peaked by 150 fs and remained so until,∼300 fs. Energy and angle resolved (EARN) spectra were calculated for the ejected atoms. The peak of the energy distribution shifted to lower energies at larger ejection angles, and the angular distributions became broader for lower energy particles. Both results agree with recent experimental data, and with a simple model proposed bg Garrison. Our results suggest that the detailed structure of the surface layer is very important in the sputtering process.
Atomic Beam Interactions with Silicon (111) Surfaces: A Molecular Dynamics Study
Authors: Dodson Brian W. , Taylor Paul A. 
Published: March 2011

AbstractLow energy (5–20 eV) atomic beam-surface interactions have been studied using a molecular dynamics technique. Silicon atoms are directed at an unreconstructed (111) silicon substrate either perpendicular to the surface or at grazing angles of incidence from 10–35°. The Si-Si interaction is treated using an empirical many-body silicon potential so that the effects of covalent bonding are included. At general beam orientations relative to the surface, low energy atoms are rapidly adsorbed at the surface, whereas at higher energies they either bounce off the surface or penetrate into the substrate. However, when the surface component of beam momentum is parallel to a (100) symmetry direction, Si atoms, under certain conditions, are found to channel along the surface rows, resulting in very little local excitation of the surface geometry and only gradual energy loss. The vertical momentum is carried away by substrate lattice vibrations, and the particle is guided along the surface by interaction with the atoms making up the surface ‘half-channels’. This surface channeling effect offers considerable promise for delicate control of the beam-induced annealing/growth of non-equilibrium surface geometries, and thus for high-quality growth at low temperatures.
The Competition between Ion Beam Induced Epitaxial Crystallization and Amorphization in Silicon: The Role of the Divacancy
Authors: Linnros J. , Elliman R. G. , Brown W. L. 
Published: March 2011

AbstractThe transition from ion induced epitaxial crystallization to planar amorphization of a preexisting amorphous layer in silicon has been investigated. The conditions for dynamic equilibrium at the transition were determined for different ion species as a function of dose rate and temperature. The critical dose rate for equilibrium varies exponentially with 1/T, exhibiting an activation energy of ∼1.2 eV. Furthermore, for different ions, the critical dose rate is inversely proportional to the square of the linear displacement density created by individual ions. This second order defect production process and the activation energy, which is characteristic of divacancy dissociation, suggest that the accumulation of divacancies at the amorphous/crystalline interface controls the balance between crystallization and amorphization.
Annealing Kinetics during Rapid and Classical Thermal Processing of Laser and Implantation Induced defects in Silicon
Authors: Adekoya W. O. , Muller J. C. , Siffert P. 
Published: March 2011

AbstractThe annealing behaviour of electrically-active defects in-duced in virgin n-type silicon by-Nd-Yag Laser (1.6 J cm−2,0.53 μm) irradiation has been investigated with Deep Level Transient Spectroscopy (DLTS). The observed defects : E(0.32 eV), E(0.45 eV) and E(0.53 eV) are characteristic of laser treated silicon, and have been reported by a number of workers. Using a rapid thermal furnace at 600°C for durations between 10 and 60s, we have observed a linear decrease in the concentration of these defects, and for times T > 60s, they are seen to disappear. A similar result was obtained in studies carried out on both vir-gin and implanted p-type silicon. This is in sharp contrast to the classical furnace annealing which requires much longer du-rations (20–30 min) at the same temperature (600 °C) in order to obtain the same results. A study of the annealing kinetics for the E(0.32 eV ;σn = 8 × 10−16 cm−2) level between 500 and 650°C in steps of 50°C for the two processes confirms this tendency for all processing temperatures, and shows a difference in ac-tivation energy of practically the same order of magnitude as the ionization energy of the defect (i.e. = 0.31 eV). Induced defects in high temperature > 1000°C in rapid thermal processed (RTA) n-type Si, also annealed out after a further 600°650 °C, 60 s RTA treatment. These results suggest that defect annealing is not a purely thermal mechanism, and lend strong support to the idea of an ionization induced enhancement.
Sulfur Segregation in Ion-Implanted and RTA'd Silicon
Authors: Herring R. A. , Clearfield H. M. 
Published: March 2011

AbstractThe segregation of 6 Mev S-implanted Si during RTA between 700 and 1200 °C has been closely studied. A model has been proposed in which self-interstitial atoms induce S to segregate into the bulk Si at ∼700°C and vacancies induce S to segregate towards the implanted surface at the higher temperatures. The binding energy between the SIA and S has been measured to be ∼0.5 eV.
UV Photon-Assisted Refractory Metal Deposition
Authors: Kovall G. A. , Matthews J. C. , Solanki R. 
Published: March 2011

AbstractWe have been investigating deposition of tungsten and molybdenum films at lover temperatures than conventional CVD processes with the aid of ultraviolet photons. The photon source is a high intensity, medium-pressure mercury lamp. W and Mo films have been deposited from their respective hexacarbonyls. W films have also been obtained by photon enhanced reduction of tungsten hexafluoride. In all cases films were deposited over 75 mm diameter substrates, which included quartz, silicon dioxide, and silicon wafers. The deposition system, conditions and the properties of the photodeposited films are presented.
Microfabrication Technologies for Advanced VLSI Devices
Authors: Horiike Y. , Yoshikawa R. , Okano H. , Nakase M. , Komano H. , Takigawa T. 
Published: March 2011

AbstractRecent progress in microfabrication technologies for advanced VLSI devices, such as 16M and 64MDRAM, is presented. First, an EB delineator with a vector-scanned VSB on a moving stage has been developed for printing 0.25 μm patterns employing PMMA, high dose exposure, and 50 KeV EB. Optical lithography also has been extended toward lower submicron geometry. A Krf excimer laser reduction projection system, using a quartz/CaF2 lens, resolves successfully 0.35 μm patterns. Ga field ion beam technology has been developed with new applications in fuse-cutting of redundancy and in optimizing sense amplifier by cutting transistor gates in the SRAM device. For fine line etching technology, collimated reactive ions produced by 10-3 Torr magnetron discharge achieves deep Si trench etching and tapered Al etching by using a polymer deposition process in addition to the original thin sidewall film. Finally, a damage-free excimer laser etching process has been developed which can etch n+ poly-Si with resist mask and with pattern transfer using an optics down to 0.5 μm and 0.9 μm resolutions respectively.
Laser Photochemical Vapor Deposition of Ge Films (300 ≤ T ≤ 873 K) from GeH4: Roles of Ge2H6 and Ge
Authors: King K. K. , Tavitian V. , Geohegan D. B. , Cheng E. A. P. , Piette S. A. , Scheltens F. J. , Eden J. G. 
Published: March 2011

AbstractThe photochemical growth of polycrystalline and amorphous Ge films on SiO2, GaAs and NaCl by photodissociating GeH4 with excimer laser radiation in parallel geometry is reported. For substrate temperatures (TS) below the pyrolytic threshold for GeH4 (553 K), two distinct regions of film growth are observed. In the 425< TS < 553 K range, the ultraviolet (UV) laser “seeds” the reactor with Ge2H6 which readily pyrolyzes at the surface, forming several monolayers of Ge which subsequently catalyze the pyrolysis of GeH4. The activation energy (Ea) in this region is the same as that for the normal CVD growth of Ge from GeH4 (Ea = 0.9 eV). If, however, the laser is pulsed throughout the film growth run, Ea falls by a factor of at least 2 and growth is observed for TS as low as 300 K. In this laser sustained region, film growth ceases in the absence of UV laser radiation. These results clearly demonstrate the ability of a UV laser to alter the reactor chemistry and dictate the species responsible for film growth.
Comparison of the Processes Induced by Mercury Lamp and ArF Excimer Laser Photoassisted CVD of a-Si:H Films
Authors: Fuchs C. , Fogarassy E. 
Published: March 2011

AbstractWe compare, in this study, the photoassisted processes for silicon deposition using both a low pressure mercury lamp and an ArF excimer laser for the specific case where the SiH4 gas is sealed in the reaction chamber.
Modelling of Hg(3P1) Photosensitization of SiH4 and Surface Reactions of the SiH3 Radical
Authors: Perrin Jérome , Biroekhuizen Ton 
Published: March 2011

AbstractWe present an experimental study and modelling of gas phase and surface processes involved in mercury-sensitized decomposition of SiH4, leading to hydrogenated amorphous silicon (a-Si:H) film deposition in a parallel plate reactor. The total surface reaction proabability β and the sticking probability s of SiH3 on a growing a-Si:H film are determined in the 40° – 350°C temperature domain. At 100°C β ≈ 0.1 ± 0.01 whereas s ≈ β/4 which reveals an intense radical recombination on the surface. Both β and s increase as a function of temperature. At 350°C β reaches 0.21±0.01. These results are interpreted by a precursor state model for SiH3 adsorption.
Stepwise Monolayer Growth of GaAs by Pulsed Laser Metal Organic Vapor Phase Epitaxy
Authors: Doi Atsutoshi , Aoyagi Yoshinobu , Namba Susumu 
Published: March 2011

AbstractAtomic layer epitaxy (ALE) of GaAs by pulsed laser metal organic vapor phase epitaxy is reported. Suspension of Ga deposition at 100% coverage is an essential part of the growth mechanism for ideal ALE. This is achieved by a photo-catalytic decomposition of adsorbed trimethylgallium (TMG). Selective enhancement of the decomposition rate for adsorbed TMG on As, with no enhancement for that on Ga is the main reason for suspension of Ga deposition at 100% coverage. A decomposition rate for TMG on As which is about 100 times faster than that on Ga is estimated from a comparison between theory and experiment.
Alternative Reactants for the Laser-Assisted Deposition of Silicon Nitride on Metals.
Authors: Partridge Julian P. , Strutt Peter R. 
Published: March 2011

AbstractAn alternative approach is described for the laser synthesis of silicon nitride layers using relatively innoccuous, non-pyrophoric reactants such as hexamethyltrisilazane. The pyrolysis process produces 2000 A particles of silicon nitride and the reaction mechanisms are invesigated using infrared spectroscopic analyses. The morphology of the deposited layer is critically dependent on process conditions due to considerable differences in the coupling efficiencies of the nitride deposit and the underlying metallic substrate. The existence of a laser-generated plasma above the metal is discussed in the light of microstructural features observed.
The Role of Low-Energy Ion/Surface Interactions During Crystal Growth From the Vapor Phase
Authors: Greene J. E. , Rocketr A. , Sundgren J.-E. 
Published: March 2011

AbstractLow-energy (often < 100 eV) ion bombardment during thin film deposition is commonly used in such diverse application areas as microelectronics, optical coatings, magnetic recording layers, and hard wear resistant coatings to modify the microstructure and microchemistry of films deposited by a variety of techniques (e.g. sputtering, primary ion deposition, plasma-assisted CVD. and accelerated-beam MBE). Ion irradiation has been shown to affect every phase of deposition including nucleation and growth kinetics, crystal structure and phase stability, the average grain size and degree of preferred orientation of polycrystalline films, the epitaxial temperature of single-crystal films, defect concentrations, elemental incorporation probabilities, surface segregation, and, hence, film properties. As discussed in this brief review, a detailed understanding of many of these processes is beginning to emerge. Effects such as trapping, preferential sputtering, enhanced diffusion, and collisional mixing have been used to interpret and, in some cases, model experimental results. Nevertheless, there are still large gaps in our knowledge of the role of ion bombardment on fundamental processes such as nucleation kinetics.
Reactions of Bare Silicon Cluster Ions: Prototypical Deposition and Etching Versus Cluster Size
Authors: Mandich M. L. , Reents W. D. , Bondybey V. E. 
Published: March 2011

AbstractPrototypical silicon deposition and etching reactions have been observed in gas phase reactions of size selected bare silicon cluster ions at room temperature. Laser evaporation of bulk silicon just outside the ion cell of a Fourier transform mass spectrometer produces abundant positive and negative silicon cluster ions. These cluster ions are trapped inside the cell for subsequent study of their bimolecular reactivity with various neutral reagents. Deposition type reactions occur with silanes, e.g. CH3SiH3, and increase the number of silicon atoms in the cluster. Etching reactions occur in reactions with certain halogen or oxygen containing reagents. For example, NO2 and XeF2 react to destroy the silicon clusters by sequential loss of a silicon atom. Overall the reactivity of small silicon cluster ions correlates with chemistry which occurs at two distinct types of dangling bonds in the clusters: either a lone pair of electrons or a single unpaired electron.
The Kinetic Energy and Angular Distribution of Sputtered Polyatomic Molecules: Outline and Applications
Authors: Haring R. A. 
Published: March 2011

AbstractKinetic energy and angular distribution measurements give information about the emission mechanism of desorbed particles. For a sputtering mechanism, the energy and angular distribution is usually assumed to be of the form: Φ(E,θ)∝ E cosθ/(E+U)3 . This expression is valid for sputtered atoms and cannot be immediately applied to the sputtering of molecules, where the energy is shared between internal and external degrees of freedom. A model is presented for the kinetic energy and angular distribution of sputtered polyatomic molecules. The formalism is related to an earlier model for sputtered clusters by Können, Tip and De Vries [1]. It is assumed that the individual atoms of a molecule are given an initial momentum according to linear collision cascade properties. If the molecule does not dissociate, it is treated as an entity and carried as such through a planar surface potential barrier. The model shows a continuous transition from a fragmentation dominated behaviour at high kinetic energies to a collision-cascade-like behaviour at low kinetic energies of the sputtered molecules. The model is compared with experimental data on sputtering of Kr2, SiCl and SiF.
The Role of Single and Multi-Electron Excitations in Electron Stimulated Desorption
Authors: Avouris P H. , Bozso F. , Rossi A. R. 
Published: March 2011

AbstractWe investigate the nature of the electronic transitions which lead to the desorption of ions from adsorbate-covered metal and semiconductor surfaces. F+ desorption from F/Si occurs via a Knotek-Feibelman mechanism, while H+ desorption from H/Si and O+ from CO/metals involve multi-electron transitions. The desorption of CO+ from CO/metals and NO+ from NO/Si apparently occurs via a simple Menzel-Gomer-Redhead mechanism.
Laser-Chemical Deposition and Etching on the Metallization Level of Integrated Circuits
Authors: Johnson A. Wayne , Greenberg K. E. 
Published: March 2011

AbstractLaser-controlled chemical deposition and etching techniques were used to modify integrated circuits. This work used a pulsed laser to initiate and control the etching, by chlorine gas, of aluminum conductors. New conducting paths were then formed by laser-chemical vapor deposition of highly-doped silicon from silane and diborane. Improved conductivity of laser-deposited connectors was achieved by the selective deposition of tungsten on the silicon. These techniques were used to “rewire” an integrated circuit allowing the full evaluation of the corrected circuit design.
A High Resolution TEM Study of In-Situ Surface Oxidation of Indium III–V Semiconductors
Authors: Smith David J. , Petford-Long Amanda K. 
Published: March 2011

AbstractElectron irradiation of InP, InAs and InSb crystals within the electron microscope causes the crystallization of nearsurface amorphous material and the oxidation of bulk crystalline material. The material most commonly found in both regions is cubic In2O3, although small regions (< 5 nm) of the corresponding In-c 6mpound semiconductors are sometimes recrystallized. The observations are consistent with desorption of the anion species due to electron-beam-stimulated processes, with subsequent oxidation of residual In metal.
A Model for Silicon Dendrite Growth During Laser/Plasma Deposition from a Silane Discharge
Authors: Anderson Harold M. , Hargis Philip J. 
Published: March 2011

AbstractA model for dendrite growths in polycrystalline Si films formed during laser/plasma deposition with a silane discharge and a pulsed KrF laser has been developed. The model assumes a thin (less than 10 nm) amorphous silicon (a-Si) film is deposited on a substrate prior to phase transformation due to laser heating. The observed dendritic structure of the overall polycrystalline Si films is attributed to Si crystals shooting from an excessively supercooled Si liquid bath. Supercooled liquid forms since the melting point for a-Si can be reached at relatively low KrF laser fluences. Latent heat evolved at the solid-liquid interface induces an interface temperature higher than that of the melt and the requisite negative temperature gradient for absolute bath supercooling. Since the formation of an undercooled liquid by fast melting a-Si is also an important first step in explosive crystal regrowth studies, these results may have important implications for crystal growth and transient annealing. A conical approximation model is used in this study to characterize the stability of the dendrite tip in terms of local temperature gradients, i.e., the degree of undercooling at the tip of the parabolic dendrite. The degree of undercooling and hence the tip radius appears to be significantly affected by small changes in the laser fluence. Stability criteria lead to a relationship between regrowth velocity, V, and the tip radius, R, of the form VR2= constant. The size and stability of the dendrite tip is determined from a balance between the destabilizing force due to thermal diffusion and the stabilizing capillary force. Based on the observed tip radii formed at laser fluences from 0.13 to 0.25 J/cm2, the model predicts regrowth velocities in a range between 2.0 and 20 m/s – values consistent with transient annealing studies of a-Si
Oxygen Exchange Phenomena in SIO2 During Microwave-Discharge Plasma Oxidation
Authors: Kimura Shin-Ichiro , Murakami Eiichi , Warabisako Terunori , Mitani Eisuke , sunami Hidho 
Published: March 2011

AbstractThe oxygen migration process during microwave-discharge plasma oxidation of Si is investigated using 18O as a tracer. The exchange phenomena between migrating oxygen and its counterpart in SiO2 are observed. When plasma grown oxide (Si 18O2) is further oxidized in 18O-enriched plasma. 18O is observed both at the SiO2 /Si interface and in the bulk of Si16O2. For the reversed case. i.e. Si18 O2 is oxidized in 18O plasma, the total amount of pre-existing 18O decreases. The suppression of 18O is more drastic in the surface region. These oxygen distributions indicate that oxygen migrates toward the interface accompanied by oxygen exchange.
Fine Line Patterning By Focused Ion Beam Induced Decomposition of Palladium Acetate Films
Authors: Harriott L. R. , Cummings K. D. , Gross M. E. , Brown W. L. , Linnros J. , Funsten H. O. 
Published: March 2011

AbstractFine conducting features have been produced on Si and SiO2 substrates by irradiation of spin-on palladium acetate, [Pd(O2CCH3)2]3 films with a submicron focused ion beam. The exposures were made with a 20 keV Ga+, focused to a 0.2 micrometer spot. Electrical conductivity measuremnents were made on the resultant features as a function of ion dose for linewidths of one and ten micrometers. The sheet conductivity in the two cases was comparable and increased dramatically in the dose range between 2×1014 and 5×1014 ions/cm2. The conductivity of the exposed lines was further increased after heating in a hydrogen atmosphere. Measurements of carbon and oxygen content indicate that even at the highest ion doses a significant amount of organic material remains. Results are compared to those for 2 MeV He+ and Ne+ broad beam exposures. Potential applications are also discussed.
Materials Surface Processing with Excimer Lasers
Authors: Elliott David J. , Piwczyk Bernhard P. 
Published: March 2011

ABSTRACTThe continued reduction of VLSI circuit geometries together with increasingly higher levels of circuit integration create the demand for new circuit fabrication technologies. One of the limitations of current IC fabrication technology is the use of high temperature processing. High temperatures severely distort silicon wafers, causing loss of geometry control and a subsequent reduction of device yield. Excimer laser technology, at very short ultra-violet wavelengths offers the possibility of extremely low temperature processing, including the following major applications: Photoresist exposure, photoresist ablation over alignment marks, annealing and etching. In addition, applications in circuit personalization and fiber optics appear as very promising new applications for excimer laser technology in the electronics industry.
Electrical Characterization of Some Native Insulators on Germanium
Authors: Gregory O. J. , Crisman E. E. , Pruitt Lisa , Hymes D. J. , Rosenberg James J. 
Published: March 2011

ABSTRACTPreliminary characterization of two native insulators on germanium is reported. A technique for preparing oxide by a room temperature chemical technique (wet chemical oxidation) is described. Compositional data based on IR transmission and ellipsometry, as well as characteristics of MOS capacitors based on this film are given. Also, compositional and electrical characterization of nitrided atmospheric pressure oxides are reported here. These films have very low fixed charge and interface state densities, and show excellent potential for use as gate insulators in a germanium MOS technology.