bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic Level Investigations of W-Si Multilayers by High Resolution Tem and X Ray Scattering
Authors: Nutt S. R , Keem J. E. 
Published: March 2011

ABSTRACTWe have prepared multilayer films of W-Si with bilayer repeat spacing from approximately 1.5 nm to 9 nm and performed high resolution electron microscopy and low angle x-ray scattering on them. Average composition estimates as inferred from deposition conditions, x ray scattering and electron microscopy are compared. Determinations of the individual layer thickness ratios by electron microscopy and x ray scattering vary significantly from expectations as the bilayer thickness approaches 1.5 nm. Layer intermixing to increase as the bilayer thickness decreases. Composition profiles as inferred from the Cuk x ray profile are compared to those inferred from the high resolution electron micrographs. Visual observations from melectron microscopy are presented indicating that the interface roughness is rapidly damped in the W-Si multilayer system. Estimates of the layer uniformity are made from the high resolution images.
Vacancy-Type Defects in Ion-Implanted Si Studied By Slow Positron Beam
Authors: Hautojdärvi P. , Huttunen P. , Mäkinen J. , Punkka E. , Vehanen A. 
Published: March 2011

ABSTRACTVariable-energy positron beam studies have been made on ion implanted silicon. After 35, 60 and 100 keV H+ implantation a clear separation between vacancy and H atom distributions was found. In 100 keV As+ and P+ implanted Si the damaged layer extends to 300 and 400 nm, respectively, far beyond the the range of implanted atoms and the amorphous layer. Effect of thermal and laser annealing is also discussed.
Electrical Characterization of Silicon With Buried Defects
Authors: Honeycutt J. , Radzimski Z. , Kola R. R. , Salih A. S. M. , Rozgonyi G. A. 
Published: March 2011

ABSTRACTDepth-dependent electrical characterization of epitaxial silicon extrinsically gettered with intentionally introduced misfit dislocations is described. To study the effect of buried defects on minority carrier lifetime, a modified Zerbst analysis of the MOS capacitance vs. time response was used to determine generation lifetime as a function of space charge region width. In addition, SEMEBIC imaging at different electron beam energies and EBIC imaging of cross-sections were used to investigate the depth-dependent electrical behavior of these materials.
Depth-Dependent Character of Extended Defects in Ion-Implanted and RTA'd Si
Authors: Herring Rodney A. 
Published: March 2011

ABSTRACTThe character of extended defects formed in high-energy S-ion implanted and rapid thermal annealed (RTA'd) Si has been found by transmission electron microscopy (TEM) to be dependent on the depth at which the defects have formed in the ion-implanted regions. Si implanted with 6 MeV S-ions and RTA'd at 1000°C for 10 s showed a buried layer of extended defects with unfaulted loops towards the top and faulted loops towards the bottom. At higher S fluences, all the loops were unfaulted, some loops coalesced to form a dislocation network, and SiS precipitates were formed. At higher RTA temperatures, all the loops were unfaulted. A few possibilities that could explain the difference in defect character will be discussed.
Gold-Silicon Interfaces: High Resolution Electron Microscopy Reactions. Precipitation and Subsurface Gettering
Authors: Carpenter R. W. , Kim M. J. 
Published: March 2011

ABSTRACTDeposition of Au on exsitu cleaned (100) Si wafers resulted in the formation of a discontinuous polvcrvstalline Au layer containing lattice defects. On parts of the interface Au and Si were separated by a thin oxide layer, but elsewhere were in direct contact, with no evidence of metastable phase formation. Post deposition heating to 1000°C. well above the 370°C eutectic temperature of the system, caused formation of a reaction zone at the interface, and disappearance of the thin oxide layer. No amorphous phases formed during cooling. Quenching produced small Au precipitates in Si-rich regions. If the wafer contained dislocations. Au precipitation was observed on subboundaries directly connected to the Au/Si interface, but not on dislocations remote from the interface.
On the Diffusion of Oxygen Dimer in a Silicon Crystal
Authors: Snyder Lawrence C. , Corbett James W. , Deák Peter , Wu Rongzhi 
Published: March 2011

ABSTRACTWe have made MINDO/3 calculations on a 47 silicon atom molecular cluster to model the diffusion of oxygen in silicon crystal. For interstitial oxygen (O1), we compute an activation energy for diffusion of 2.49 ev. We compute a binding energy of 0.1 ev. when two isolated interstitial oxygen atoms bond to a common silicon atom of the lattice. This complex (O2) is computed to move through the lattice with an activation energy of 1.36 ev. The diffusion path is through a four-member ring intermediate structure. We conclude that the diffusion constant for (O2) is eight orders of magnitude greater than that of (O1).
Nitrogen-Oxygen Complexes in Silicon
Authors: Suezawa Masashi , Sumino Koji 
Published: March 2011

ABSTRACTSeveral series of optical absorption lines are found in the wavenumber range 190–270 1/cm in as-grown crytals of n-type Si involving oxygen and nitrogen simultaneously. They are related to the electronic transitions associated with five kinds of shallow donors each consisting of nitrogen and oxygen atoms (N-O complex). The analysis of the generation kinetics shows that the complex of the main type consists of one oxygen atom and two or three pairs of nitrogen atoms.
Effect of Rapid Thermal Processing on Oxygen Precipitation in Silicon
Authors: Hawkins G. A. , Lavine J. P. 
Published: March 2011

ABSTRACTThe precipitation of oxygen in silicon can be initiated by both homogeneous and heterogeneous nucleation mechanisms. Homogeneous nucleation has been studied in much greater detail; however, in some cases, superior contaminant gettering has been reported for precipitation processes believed to be based on heterogeneous nucleation. In this study, we use rapid thermal annealing (RTA) to demonstrate conclusively that the nucleation mechanism for one such process is, in fact, heterogeneous. We also investigate the sensitivity of precipitation to slight alterations in thermal process steps. We interpret our results in terms of point-defect-induced changes in the critical radius (Rc) for precipitate growth.
Theory of Hydrogen Reactions in Silicon
Authors: Walle Chris G. Van De , Bar-Yam Y. , Pantelides S. T. 
Published: March 2011

ABSTRACTWe report first-principles total-energy calculations for H atoms in a Si lattice. Our results for single H atoms are presented in the form of total-energy surfaces, providing immediate insight in stable positions and migration paths. We examine the stability of different charge states (H+, H0, H−) as a function of Fermi-level position, and its impli-cations for H diffusion in p-type vs. n-type material. The results are used to scrutinize and supplement existing understanding of experimental observations. We also study the co-operative interactions of several H atoms, and propose a novel mechanism for H-induced damage.
The Structure of the Boron-Hydrogen Complex in Silicon
Authors: Marwick A. D. , Oehrlein G. S. , Barrett J. H. , Johnson N. M 
Published: March 2011

ABSTRACTChanneling and lattice location has been used to investigate the structure of the boron-hydrogen complex in crystalline silicon. The positions of both the boron and hydrogen atoms have been determined. The results are compared with Monte-Carlo simulations. The boron atom in the B-H pair is found to be displaced from a substitutional site by 0.28±0.03Å, while the hydrogen atom is predominantly at a bond-center site, with a small proportion in a back-bonded position.
Hydrogen Neutralization of Shallow-Donor Impurities in Single-Crystal Silicon
Authors: Johnson N. M. , Herring C. 
Published: March 2011

ABSTRACTNew data are presented that considerably strengthen the conclusion, reported previously, that hydrogen can passivate shallow donors in silicon by associating with them to form neutral complexes. Effects of inhomogeneity of doping with depth have been eliminated in the new experiments; the observed increase of the effective Hall mobility after hydrogenation requires neutralization of ionizeddonor scattering centers.
Passivation of N-Type Silicon by Hydrogen
Authors: Bergman K. , Stavola Michael , Pearton S. J. , Lopata J. 
Published: March 2011

ABSTRACTInfrared spectroscopy has been used to study hydrogen passivation of P, As, and Sb donors in Si. The spectra show several new absorption bands due to donor-H complexes. By comparing spectra after different heat treatments it is shown directly that the passivation is due to complex formation.
Interactions Between Hydrogen and Silicon Acceptors in p-Type GaAs:Si
Authors: Chevallier J. , Pajot B. , Jalil A. , Mostefaoui R. , Rahbi R. , Bolssy M. C. 
Published: March 2011

ABSTRACTWe show that silicon acceptors can be neutralized in p-type GaAs: Si. SIMS analysis shows that the deuterium concentration closely follows the net acceptor concentration. Infrared absorption spectroscopy reveals lines at 2094.7cm-1 and 1514.5cm-1 in hydrogenated and deuterated samples respectively. The ratio r of the two frequencies is 1.383 indicating that the lines are related to hydrogen isotopes. The reduction of the intensity of the local vibrational mode (LVM) of SiAs after neutralization is consistent with the formation of SiAs-H bonds. From SIMS data, it is concluded that most of the hydrogen present in the passivated material is complexed with silicon. A microscopic model of the Si-H complex is proposed.
Evidence for Complexes of Hydrogen with Impurities or Defects in Bulk III-V Materials
Authors: Clerjaud B. , Côte D. , Krause M. , Naud C. 
Published: March 2011

ABSTRACTSeries of sharp optical absorption lines around 2200 cm-1 in GaP, 2000 cm-1 in GaAs, and 2300 cm-1 in InP are observed in bulk materials. They are shown to be due to stretching local modes of vibration of P-H or As-H bonds, the hydrogen sitting nearby an impurity or defect. The origin of the hydrogen contamination of the bulk materials is discussed.
A Determination of the Symmetry of EL2 Using Ballistic Phonon Transmission
Authors: Culbertson J. C. , Strom U. , Wolf S. A. 
Published: March 2011

ABSTRACTWe have measured the time resolved transmission of short pulses of ballistic phonons in a GaAs crystal known to contain the intrinsic defect EL2. These measurements were performed for phonons propagating along several high symmetry directions at 2K. Measurements were made both before and after the crystal was irradiated with 1.06 μm light to convert EL2 from its ground state to its metastable state. The changes in phonon transmission measured for the different phonon polarizations and propagation directions lead us to associate a trigonal symmetry with the defect whose phonon scattering has changed. The identification of this defect as EL2 is discussed below.
On the Origin of EL2 Intracenter Absorption Band in GaAs
Authors: Skowronski M. 
Published: March 2011

ABSTRACTAn alternative interpretation of optical absorption spectra due to intracenter transition within EL2 defect in GaAs is provided. The arguments are presented that states originating from the L-valley of the conduction band can account for the presence of the wide absorption band, the no-phonon line and the observed uniaxial stress splittings. Using the analogy to the DX center, this model presents an explanation for the existence of the metastable state of EL2.
Point Defects, Dislocations in GaAs and Material Homogeneity
Authors: Bourgoin J. C. , Bardeleben H. J. von , Lin H. , Stievenard D. 
Published: March 2011

ABSTRACTCombined positron annihilation and differential thermal analysis have shown that, in bulk GaAs materials, dislocations are decorated with vacancy related defects which recombine with As interstitials originating from As clusters. The role of these dislocations, the role of As source of these clusters are described and the consequences on the material homogeneity discussed.
Positron Annihilation Spectroscopy of As Vacancies in As-Grown GaAs
Authors: Corbel C. , Stucky M. , Hautojärvi P. , Saarinen K. , Moser P. 
Published: March 2011

ABSTRACTPositron lifetime measurements give direct evidence on positron trapping in monovacancy defects in n-type, but not in p-type nor in semi-insulating LEC-grown GaAs. The defects are identified as As vacancies. Two Fermi level controlled transitions have been found in positron lifetime spectra at 0.03±0.01 eV and at 0.10±0.01 eV below the conduction band. We attribute them to the 2-/- and - / 0 ionisation levels of the As vacancy.
Fermi Level Stabilization in Semiconductors: Implications for Implant Activation Efficiency
Authors: Walukiewicz W. 
Published: March 2011

ABSTRACTWe propose the existence of a Fermi level stabilization energy in III-V semiconductors which provides a reference level for the electronic part of defect annihilation energies. It is shown that the position of the stabilization energy with respect to the band edges determines the maximum free carrier concentration which can be obtained through doping. The proposed model accounts for previously unexplained trends in implant activation efficiency in III-V semiconductors.
DX Center Analysis in Sn DOPED AlGaAs Layer of Double Heterostructures
Authors: Kaniewska M. , Kaniewski J. 
Published: March 2011

ABSTRACTCapacitance as well as photovoltage response methods have been used to analyse DX centers in the N–type AlGaAs:Sn layer of double heterostructures. DLTS spectra have revealed two deep traps. The first center (ΔE1 = 0.20eV) has been interpreted as the DX center related to Sn. In this paper, it is suggested that the second trap, with thermal activation energy equal to ΔE2 = 0.33eV, is also a DX center due to Sn, connected with another final state (the L minimum) of thermal processes. C-T characteristics and DLTS spectra have been compared with photovoltage spectra to find a correlation between the trap populations and Al content. The binding energy of the trap 2, as well as the temperature dependence of the electron capture cross-section, have been determined from measurements of the transition region width. Photoionization measurements confirm that there is large lattice relaxation when an electron is captured at the trap.
Enhanced Interdiffusion Effects in Compound Semiconductors
Authors: Petroff P. M. 
Published: March 2011

ABSTRACTThis paper reviews the principal processes involved in the enhanced interdiffusion of elements across interfaces between two III-V compound semiconductors. Implantation enhanced interdiffusion effects in GaAs-Gal−xAlxAs are compared for single Quantum Well structures and Superlattice structures. Measurements indicate a marked difference in the annealing and enhanced interdiffusion kinetics between these 2 types of structures.
Metastable Phases and the Molecular Beam Epitaxy of Metal Silicides
Authors: Gibson J. M. 
Published: March 2011

ABSTRACTThe growth of the epitaxial silicides NiSi2 and CoSi2 on Si is discussed from observations made by in-situ transmission electron microscopy. In particular, we observe the occurrence of epitaxial metastable phases which arise from the dominance of interface energy in extremely thin films. Such phases relate to the thickness dependence of the microstructure in these silicides and may be expected to occur in many binary and more complex thin film systems.
Kinetics of Silicon Oxide Thin Film Deposition From Silane and Disilane with Nitrous Oxide.
Authors: Chapple-Sokol Jonathan D. , Giunta Carmen J. , Gordon Roy G. 
Published: March 2011

AbstractA mechanistic study of the deposition of silicon oxide films (SiOx, 0 < x ≤2) from silanes with nitrous oxide was performed. The depositions of non-stoichiometric films from silane and stoichiometric silicon dioxide from disilane were dominated by SiH2 generation from the decomposition of the silicon-containing reactant. The depositions of stoichiometric films from silane were found to follow chain reaction kinetics initiated by the homogeneous decomposition of N2O.
Radiation Response of Thin Oxides Grown By Rapid Thermal Oxidation and Rapid Thermal Annealing Techniques
Authors: Schubert W. K. , Seager C. H. 
Published: March 2011

AbstractHigh quality, 20 to 30 nm thick SiO2 films were grown using rapid thermal oxidation techniques. Metal-oxide-semiconductor (MOS) capacitors formed with these oxides were characterized electrically using low and high frequency capacitance measurements. The effects of post oxidation annealing (POA) ambient, temperature and duration on the initial oxide properties and the radiation response of the MOS capacitors were determined. The addition of a small amount of O2 to the POA ambient significantly reduced the radiation induced hole trapping and interface state creation, particularly for the higher POA temperatures. In addition, annealing and reirradiation experiments were carried out and showed that both the trapped charge and interface state buildup were completely reversible after anneals at 400°C. This repeatability argues against interface state creation models which involve irreversible changes in the atomic arrangements near the interface.
Photo-Oxidation of Silicon: Reaction Mechanisms and Film Structure
Authors: Boyd Ian W. 
Published: March 2011

AbstractThe use of intense photon beams to initiate silicon oxidation is reviewed. In particular, recent experiments involving visible photons are discussed, which confirm a thermal domination and a clear photon enhancement. With equal powers of 488 and 514 nm radiation, the latter initiates faster reaction rates. Structural studies of the films are also reported using IR spectrometry, where we find broad similarities and intriguing differences the between laser and furnace grown films.
Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.
Authors: Massoud Hisham Z. 
Published: March 2011

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.
Structure of Sol-Gel Silic
Authors: Brinker C. J. , Brow R. K. , Tallant D. R. , Kirkpatrick R. J. 
Published: March 2011

AbstractCombined Raman, 29Si NMR and reactivity studies of silica gels indicate that dehydroxylation of the silica surface results in cyclotrisiloxane species with reduced Si-O-Si bond angles and altered acid/base characteristics. XPS experiments indicate that the expected 0.35 eV shifts in Si2p and O1s binding energies due to the reduced bond angles are hidden within broad peaks due to the remaining hydroxyls. Additional Si2P, OlS, and ClS peaks are also observed and are postulated to result from preferential adsorption of extrinsic C-containing species on sites with enhanced acid/base properties.
Process Dependent Morphology of the Si/SiO2 Interface Measured with Scanning Tunneling Microscopy
Authors: Hecht Michael H. , Bell L. D. , Grunthaner F. J. , Kaiser W. J. 
Published: March 2011

AbstractA new experimental technique to determine Si/SiO2 interface morphology is described. Thermal oxides of silicon are chemically removed, and the resulting surface topography is measured with scanning tunneling microscopy. Interfaces prepared by oxidation of Si (100) and (111) surfaces, followed by post oxidation anneal (POA) at different temperatures, have been characterized. Correlations between interface structure, chemistry, and electrical characteristics are described.
The Mechanism of Oxidation of SiGe.
Authors: LeGoues F. K. , Rosenberg R. , Nguyen T. , Meyerson B. S. 
Published: March 2011

AbstractWe have studied the oxidation mechanism of SiGe alloys, prepared by UHV/CVD. Ge is found to be completely rejected from the oxide and to pile up at the oxide/substrate interface. In the case of thick SiGe layers, this can give rise to very heavily concentrated layers of SiGe (up to 80% Ge) several hundreds of angstroms thick between the oxide and the substrate. The oxidation of Si then proceeds by Si diffusing though the Ge-rich layer. When only a thin layer of Ge is present on top of Si at the start, it acts as a marker, moving, unchanged, with the SiO2/Si interface. The rate of oxidation is enhanced in this case. The atomic motion and chemical reactions involved in the process are discussed and possible mechanisms are described to explain the data. Oxidation of a SiGeB sample is also discussed and compared with the previous case.
Low Temperature Plasma Enhanced CVD of ‘Device Quality’ Silicon Dioxide.
Authors: Batey J. , Tierney E. , Nguyen T. N. , Stasiak J. W. , Li J. 
Published: March 2011

AbstractAs silicon-based technologies move towards submicron dimensions, vertical and three dimensional structures, the need for reduced thermal processing becomes more evident than ever. Currently, insulator (usually SiO2) growth and deposition contribute significantly to the total thermal budget, and it is clear that this will have to be reduced in future processes. In addition, many other applications require the deposition of high quality dielectrics at very low substrate temperatures, typically ≳ 350°C. Plasma-enhanced chemical vapor deposition (PECVD) is a technique which can be used to deposit insulators at suitably low temperatures, although it tends to produce SiO2 which exhibits poor electrical and physical properties and which forms poor interfaces with semiconductor substrates. Direct exposure to the high energy environment of the plasma is generally thought to be the main reason for this.
Conduction and Injection in Off-Stoichiometry Oxides
Authors: Chang K.-T. , Lam C. , Rose K. 
Published: March 2011

ABSTRACTSlightly silicon rich oxides or off-stoichiometry oxides (OSO) have been prepared by LPCVD. When R, the nitrous oxide/silane ratio, equals or exceeds 30 these films have the refractive index and CV characteristics of stoichiometric CVD oxide. Injection into these oxides by oxides richer in silicon has been compared with injection into thermal oxides. We find that silicon rich oxides with higher silicon content having the same Research-article values provide the same enhancement of electron injection into thermal oxides and off-stoichiometry oxides. Conduction in off-stoichiometry oxides depends on preparation, but can be accounted for by tunneling between islands.