bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence Of Substrate Off-Cut On The Defect Structure In Relaxed Graded Si-Ge/Si Layers
Authors: Samavedam Srikanth B. , Romanato F. , Goorsky M. S. , Fitzgerald E. A. 
Published: April 2011

AbstractRelaxed graded Si-Ge/Si layers can be used in a variety of micro-electronics applications such as templates for III-V/Si integration, in high speed field effect transistor (FET) structures and as detectors in optical communication. Each of these applications requires a different final Ge concentration in the graded Si-Ge layer. With increasing Ge content in the graded layer, some of the materials concerns that need to be addressed are- (i) a high surface roughness, (ii) the formation of dislocation pile-ups, and (iii) an increase in the threading dislocation density. We have shown that there is a substantial improvement in the surface roughness and the dislocation pile-up density of the graded Si-Ge layers by depositing on (001) 6° off-cut substrates. The substrate miscut also facilitates favorable intersections of {111} planes that aid reactions between the 60° dislocations to form edge dislocations with Burgers vectors of the type 1/2<110> and <100> resulting in a novel hexagonal dislocation structure. Such reactions occurred more readily in the Ge-rich regions of the graded layers where the growth temperature was high enough to aid dislocation climb. The edge dislocations with in-plane Burgers vectors lack a tilt component and the decreased rate of tilting in the Ge-rich regions is confirmed by triple crystal X-ray reciprocal space maps. This novel dislocation structure offers opportunities to explore new processes which may eliminate spatially variant strain fields in relaxed epitaxial layers.
Defects In Low Temperature Mbe-Grown Si And Sige/Si Structures
Authors: Chen W. M. , Buyanova I. A. , Monemar B. 
Published: April 2011

AbstractWe review our recent experimental results on important grown-in non-radiative defects in Si and SiGe/Si heterostructures grown by molecular beam epitaxy (MBE) at low temperature. Several types of such defects have been revealed by the optically detected magnetic resonance technique and were shown to play an important role in carrier recombination. Among them a dominant defect is identified to be the vacancy-oxygen (V-O) complex. Experimental evidence on the formation mechanisms of these non-radiative defects points at a low surface adatom mobility during low temperature growth as a major cause, and also ion bombardment as occurs e.g. during potential enhanced doping. Based on the gained knowledge, educated attempts by post-growth hydrogen and thermal treatments have been made to remove these harmful defects and to improve the radiative efficiency of the material.
EL2-Induced Upconversion Luminescence In GaAs
Authors: Alex V. , Iino T. 
Published: April 2011

AbstractNear band gap luminescence in bulk-grown semi-insulating GaAs is excited in a two step process via the EL2 defect. While the conventionally excited photoluminescence of our samples is dominated by conduction band to acceptor transitions, the upconversion process selectively excites donor acceptor pair transitions. Illumination near the maximum of the EL2- photoquenching band at 1064 nm leads to a complete disappearance of the so called upconversion photoluminescence (UPL). Excitation with light of shorter wavelengths however only partially quenches the UPL. Excitation between 850nm and 900nm completely regenerates the UPL. The characteristic photorecovery transients of the UPL are described by the EL2 regeneration mechanism via the population of the acceptor level of the metastable EL2 by hot electrons. The recovery of the EL2 by simultaneous illumination with above and below band gap light enables the observation of UPL at wavelengths, where the EL2-defect would otherwise be rapidly quenched. Under these conditions we observe a remarkable increase of the UPL-efficiency.
Relationship Between Hydrogen-Related Metastable Defect And EL2-Level In GaAs Crystals
Authors: Shinagawa Tatsuyuki , Okumura Tsugunori 
Published: April 2011

AbstractThe relationship between the hydrogen-related metastable defect (M3/M4) and the EL2 level in n-GaAs crystals has been investigated. We found with various kinds of GaAs crystals that the hydrogen-related metastable couple (M3/M4), first reported by Buchwald et al., has been observed only in the crystals containing the EL2 defect. This fact was further confirmed by using LT-MBE GaAs crystals before and after rapid thermal annealing (RTA). Only in the n-LT-n sample annealed at 900°C, in which the EL2 defect was formed, the metastable couple (M3/M4) appeared upon hydrogenation. As hydrogenated, the EL2 level was passivated or dissociated. From bias-annealing experiments, the M4 level was completely annihilated by annealing at 573K, where the EL2 level was restored to its original concentration. We speculated from these results that both diffused hydrogen and preexisting arsenic antisite defect (AsGa) are responsible for the formation of the metastable defect(M3/M4).
Inspection Of Recombination Active Defects For Sige And Solar Cells
Authors: Astafiev O.V. , Kalinushkin V.P. , Abrosimov N.V. 
Published: April 2011

AbstractMapping Low Angle Light Scattering method (MLALS) is proposed to study defect structure in materials used for solar cell production. Several types of defects are observed in Czochralski Si1−xGex (0.022<x<0.047) single crystals. Recombination activity of these defects is investigated. The possibility of contactless visualisation of grain boundary recombination in polysilicon is also demonstrated.
Structural And Optical Characterization Of AlxGa1−xAs Grown At Low Temperatures By Organometallic Vapor Phase Epitaxy
Authors: Wankerl A. , Emerson D. T. , Cook M. J. , Shealy J. R. 
Published: April 2011

AbstractWe report on the low temperature growth of AlxGa1−xAs by conventional Organometallic Vapor Phase Epitaxy OMVPE for a substrate temperature of 500°C and V/III ratios extending to subunity. Optical, structural and electrical qualities are assessed with double crystal X-ray diffraction, Nomarski and atomic force microscopy, 1.6K and 300K photoluminescence, Rutherford backscattering and Hall measurements. Although our low temperature grown films are of good structural and optical quality, they exhibit high background p-doping (carbon) and high levels of hydrogen passivation. A method for extracting the carbon doping levels from lattice contraction measurements is suggested. The dependence of layer composition, free carrier concentration and hydrogen passivation on growth parameters are investigated. Moreover, the effects of post-growth annealing on free carrier concentration, lattice parameter and optical qualities are studied. The influence on the bandgap of bandtail states and compressive strain due to carbon are compared.
Electrically Detected Magnetic Resonance On GaAs/AIGaAs Heterostructures
Authors: Wimbauer T. , Hofmann D. M. , Meyer B. K. , Brandt M. S. , Brandl T. , Bayerl M. W. , Reinacher N. M. , Stutzmann M. , Mochizuki Y. , Mizuta M. 
Published: April 2011

AbstractElectrically detected magnetic resonance (EDMR) has been used to study carrier recombination in GaAs/AlGaAs quantum well structures grown by molecular beam epitaxy. The spin dependent photoconductivity signals depend strongly on the electrical contact properties. Using silver paste contacts a narrow (18 G) resonance located at g = 2.001 is observed. It has been previously attributed to surface defects on GaAs. Using alloyed In-contacts other signals are detected. The dominant resonance observed at 9 GHz has an isotropic g-value of g = 1.99 with a halfwidth of 200 G and is therefore assigned to Cr4+. Other signals of considerably lower intensity are explained by the well known electron paramagnetic resonance (EPR) properties of the Gai-interstitial and the AsGa-antisite defects. EDMR performed at 34 GHz allows the experimental separation of the two sets of hyperfine lines.
Defects In 4H Silicon Carbide CVD Epilayers
Authors: Zhou L. , Pirouz P. , Powell J. A. 
Published: April 2011

AbstractThe characteristic defects of 4H-SiC homoepitaxial thin films grown on bulk substrates using chemical vapor deposition (CVD) are described based on transmission electron microscopy (TEM), atomic force microscopy (AFM) and surface decoration studies. Emphasis is placed on understanding the formation mechanism of surface triangular defects. Cross-sectional TEM observations revealed the existence of two variants of 3C-SiC inclusions in 4H epitaxial films. In the plan-view orientation, g4H = 3304 type reflections were found useful for distinguishing the two variants of 3C-SiC platelets that are present in the 4H epilayer. A decoration technique was employed to reveal the relationship between the 3C platelets and surface features, e.g., surface steps. A formation mechanism for surface triangular defects is proposed, which is partially confirmed by the etch pit patterns obtained on the epilayer surfaces after a molten KOH etch.
Charge Transient Spectroscopy Study Of Deep Centers In Cvd Diamond And Diamond-Like Films
Authors: Polyakov V.I. , Rukovishnikov A.I. , Rossukanyi N.M. , Varnin V.P. , Teremetskaya I.G. , Druz B.L. , Ostan E. , Hayes A. 
Published: April 2011

AbstractThe parameters of trapping centers in CVD diamond and Diamond-Like Carbon (DLC) films were studied by Charge Deep Level Transient Spectroscopy (Q-DLTS). The concentrations, activation energies, captures cross-section and location of the trapping centers were determined. The influence of post deposition heat treatment on the defect center parameters was studied. The Q-DLTS measurements showed that micro defects are acting as point trapping centers and have the continuous energy spectrum with one or two maximums at different energies. The nature of the trapping centers is discussed.
Field Drift Of Plasma-Induced Defects In Phosphorus Doped Si By Reverse Bias Annealing (RBA)
Authors: Takeuchi J. , Zaitsu Y. , Shimizu T. , Matsumoto S. , Wada K. 
Published: April 2011

AbstractThe property of plasma induced defects in phosphorus doped CZ silicon has been investigated by reverse bias annealing (RBA). After CF4 plasma exposure, charge density at the surface decreased since plasma induced negatively charged defects inactivated phosphorus. With the increase of annealing time, inactivated phosphorus area moved into the bulk with reverse bias of −3V. Thus it is clearly observed that negatively charged defects drifted from the surface into the bulk. The thermal dissociation energy for phosphorus-defect complexes is estimated to be 1.22eV from the Arrhenius plot of dissociation rate. These defects are likely to be Si self interstitials or vacancies.
Chemical Bonding of Fluorine Atoms in Siof Alloys: Microscopic Mechanisms for Reductions in the Dielectric Constant Relative to SiO2
Authors: Lucovsky G. , Yang H. 
Published: April 2011

AbstractSi-O-F alloys have static dielectric constants (εs) significantly lower than SiO2. Infrared absorption spectra provide the basis modeling the molecular structure of these alloys. Contributions of electronic and vibrational transitions to εs are discussed in terms of an empirical chemical bonding model. Ab initio calculations are then used to identify inductive effects of Si- F bonds on the properties of Si-O-Si groups that are back-bonded to the Si atom of the Si-F group. These calculations provide a theoretical framework for understanding how relatively low concentrations of F atoms produce the significant decreases in εs reported for Si-O-F alloys.
The Thermal Stability of Fluorine Doped Silicon Oxide Films Formed by Ecrcvd With SiF4 and O2 Gases
Authors: Lee Seoghyeong , Yoo Jae-Yoon , Park Jong-Wan 
Published: April 2011

AbstractThe reliability of SiOF films for intermetal dielectrics in multilevel interconnections of ULSIs is investigated. SiOF films were deposited by ECRCVD using H-free source gases, i.e., SiF4 and O2. The effect of post plasma treatment on the moisture absorption and dielectric properties of SiOF films were carried out in terms of air exposure time. The reliability test of Cu / TiN / SiOF / Si specimen was carried out in terms of temperatures by RTA in N2 ambient. After O2 plasma treatment, no appreciable peak directly related to moisture absorption was detected. The C-V characteristics of the O2 plasma treated SiOF film showed that the film remained to hold the sound dielectric properties even after boiling treatment. The Cu / TiN / SiOF / Si system was found to be reliable up to 600 °C.
Thermal Stability of Fluorinated SiO2 Films: Effects of Hydration and Film-Substrate Interaction
Authors: Sullivan J. P. , Denison D. R. , Barbour J. C. , Newcomer P. P. , Apblett C. A. , Seager C. H. , Baca A. G. 
Published: April 2011

AbstractThe thermal stability of fluorinated SiO2 films (SiOF) was found to be dependent on F content and the type of substrate upon which the film was deposited. SiOF films with a range of F concentrations were deposited using an electron cyclotron resonance (ECR) plasma upon Si, Al/Si, TiN/Al/Si, and Al/SiO2/Si substrates. Following deposition, the films were deliberately hydrated and/or annealed and their stability assessed. Hydration was found to only affect the high F content films. Capacitance changes with annealing in the high F content films were found to occur beginning at 200°C. These changes, which were independent of substrate type, likely occurred due to desorption of H2O in the films. After annealing of the high F content films up to 400°C, a reduction in F content was found for SiOF films on some substrates. Significant reductions were found for SiOF films on Al/Si substrates, while little or no change was found for films on TiN/Al/Si, Al/SiO2/Si, or Si substrates. Local chemical analysis of those films which showed F reduction indicated that the F profile was approximately uniform throughout the layer and did not pile-up at the interface. The substrate-dependent thermal instability exhibited by these films suggests the chemical nature or qualities of the substrate may play a role in the F reduction reaction.
Fluorinated Heteroaromatic Polyethers for Low Dielectric Constant/High Temperature Applications
Authors: Maier G. , Schneider J. M. , Hecht R. 
Published: April 2011

AbstractSynthesis and characterization of three classes of poly(arylene ether oxazole)s and poly(arylene ether thiazole)s with trifluoromethyl substituents in various positions is described. Based on these examples, the influence of the chemical structure of the polymers on properties such as glass transition temperature, solubility, and thermal stability will be discussed. Structural parameters studied are the number and nature of the heteroaromatic rings, the number and position of the trifluoromethyl groups, and the structure (flexibility, polarity) of various linking groups.
Properties of CAT-CVD Silicon Nitride Films and Their Application as Passivation Films
Authors: Okada Shinya , Matsumura Hideki 
Published: April 2011

AbstractSilicon nitride (SiNx) films have been successfully synthesized by the catalytic chemical vapor deposition (cat-CVD) method using a gaseous mixture of silane (SiH4) and ammonia (NH3). In the method, the deposition gases are decomposed by catalytic cracking reactions with a high temperature (1700°C) catalyzer near the substrates, and SiNx films can be deposited at substrate temperatures lower than 400°C without using plasma or photochemical excitation. Nearly stoichiometric Si3N4 films are formed when the flow ratio of NH3 exceeds over 100 times of that of SiH4. These cat-CVD SiNx films show excellent properties. That is, the resistivity, the breakdown voltage, the chemical etch resistance and hydrogen content in the films are almost equivalent to those of high-temperature thermal CVD films. In addition, the surface diffusion length of depositing species is about several-tens μπι and step-coverage itself is conformai. Thus, the cat-CVD SiNx films are regarded not only as a new device passivation films superior to the conventional plasma-CVD films but as a gate insulator for electon devices due to their high quality.
The Applicability of Fluorinated Silicon Nitride Film As Bottom Antireflective Layer In Deep Ultraviolet Lithography
Authors: Byung-Hyuk Jun , Sang-Soo Han , Dong-Wan Kim , Ho-Young Kang , Young-Bum Koh , Byeong-Soo Bae , Kwangsoo No 
Published: April 2011

AbstractThis study describes the use of fluorinated silicon nitride film as a bottom antireflective layer (BARL) material suitable for line-patterning in quarter-micron KrF excimer laser lithography. For the structures of photoresist/BARL (300Å)/c-Si and photoresist/BARL (300 Å )/W-Si at a wavelength of 248nm, 0% reflectance could be achieved when the refractive index (n) and extinction coefficient (k) values of the film are 2.11 and 0.68 or 2.05 and 0.59, respectively. The fluorinated silicon nitride thin films on p-type (100) Si substrates obtained by inductively coupled plasma enhanced CVD have been evaluated with the variations of NF3 flow rates under the two conditions of SiH4:N2=2:15 and 3:20 (seem). The films optical constants and reflectance were investigated by spectroscopic ellipsometry combined with a reflectance simulation program. The film n and k values at 248nm vary in the ranges of 1.67~2.35 and 0.01~0.69, respectively, depending on gas flow ratio of SiH4:N2:NF3. Low reflectance of below 5% can be obtained from reflectance simulation for two deposition conditions with a BARL thickness of 300Å. In addition, the reflectance could be reduced to almost 0% by controlling film thickness. Finally, the antireflective layer performance was investigated using KrF excimer laser lithography.
Oxidation Kinetics Of Crystalline Silicon Oxynitride
Authors: Manessis D. , Du H. 
Published: April 2011

AbstractOxidation stability of silicon oxynitride is a property of great technological significance. In this study, the oxidation behavior of stoichiometric polycrystalline Si2N2O was investigated in 1 and 0.5 atm flowing dry oxygen at 1000°‐1300°C. The oxidized Si2N2O samples were characterized using transmission and scanning electron microscopy. The oxidation kinetics were determined using profilometry in conjunction with patterned etching. Oxidation of Si2N2O resulted in the formation of amorphous SiO2. The SiO2‐Si2N2O interface was chemically and structurally abrupt. A parabolic rate law was followed during oxidation with apparent activation energies ranging from 43 to 52 kcal/mol. The relatively high activation energy values compared to that for silicon oxidation suggest that oxidation of Si2N2O is rate‐controlled by a more complex process than molecular oxygen diffusion in amorphous SiO2.
Molecular Dynamics Study Of Si/Si3N4 Interface
Authors: Bachlechner Martina E. , Ebbsjö Ingvar , Kalia Rajiv K. , Vashishta Priya 
Published: April 2011

AbstractStructural correlations at the Si(111)/Si3N4(0001) interface are studied using the molecular dynamics (MD) method. In the bulk, Si is described by the Stillinger-Weber potential and Si3N4 by an interaction potential which contains two-body (steric, Coulomb, electronic polarizabilities) and three-body (bond bending and stretching) terms. At the interface, the charge transfer from silicon to nitrogen is taken from LCAO electronic structure calculations. Using these Si, Si3N4 and interface interactions in MD simulations, the interface structure (atomic positions, bond lengths, and bond angles) is determined. Results for fracture in silicon are also presented.
Fracture in Silicon Nitride and Alumina thin Films: a Molecular Dynamics Study
Authors: Campbell Timothy J. , Nakano Aiichiro , Omeltchenko Andrey , Kalia Rajiv K. , Vashishta Priya 
Published: April 2011

AbstractFracture in thin films of silicon nitride and alumina is investigated with large-scale multiresolution molecular-dynamics (MD) simulations on parallel computers. The simulations for alumina include dynamic charge transfer effects based on electronegativity equalization. Results for structural and dynamic correlations and the effects of temperature and orientation of film on fracture dynamics and morphology of fracture surfaces are presented.
Smart‐Cut® : The Basic Fabrication Process for Unibond® Soi Wafers
Authors: Auberton‐Hervé A.J. , Barge T. , Metral F. , Bruel M. , Aspar B. , Maleville C. , Moriceau H. , Poumeyrol T. 
Published: April 2011

AbstractThe advantage of SOI wafers for device manufacture has been widely studied. To be a real challenger to bulk silicon, SOI producers have to offer SOI wafers in large volume and at low cost. The new Smart‐Cut® SOI process used for the manufacture of the Unibond® SOI wafers answers most of the SOI wafer manufacturability issues. The use of Hydrogen implantation and wafer bonding technology is the best combination to get good uniformity and high quality for both the SOI and buried oxide layer. In this paper, the Smart‐Cut® process is described in detail and material characteristics of Unibond® wafers such as crystalline quality, surface roughness, thin film thickness homogeneity, and electric behavior.
Optical Characterization of Silicon-On-Insulator
Authors: Li G. G. , Forouhi A. R. , Bloomer I. , Auberton-Herve A. , Wittkower A. 
Published: April 2011

AbstractA new technique, referred to as the “n&k Method”, is used to characterize the thin films comprising Silicon-on-Insulator (SOI). With the “n&k Method”, a non-destructive robust measurement of the thickness of both the crystalline silicon top-layer and the buried oxide under-layer, the spectra of refractive index (n), and extinction coefficient (k), and the smoothness of the interfaces is established. The “n&k Method” determines these quantities simultaneously and without multiple solutions for thickness. The non-destructive measurement of interface roughness between the buried oxide under-layer and the silicon substrate is associated with the presence of silicon islands. The native oxide that forms on SOI is also detected and measured. No initial user's input for thickness and optical constants are required in order to obtain these results. The spectra of optical constants are measured accurately and reliably.
Electron Induced Depassivation Of H And D Terminated Si/Si02 Interfaces
Authors: Devine R. A. B. , Warren W. L. , Vanheusden K. , Mourrain C. , Bouzid M‐J. 
Published: April 2011

AbstractWe have performed electron spin resonance and electrical measurements on SiO2/Si structures subjected to anneals in 5% H2/N2 or 5% D2/N2 gases and subsequently injected with electrons using corona ions and ultra‐violet radiation. Threshold voltage and transconductance measurements have also been made on 0.25 μm metal‐oxide‐semiconductor transistors subjected to 400 °C anneals in the same gases and subsequently aged by hot electron injection. The electrical data on SiO2/Si structures indicates that the density of interface states increases as a result of electron injection but that there are only minor differences between H and D passivated interfaces. The data on Pb, trivalent Si dangling bond, centers at the same interfaces observed by electron spin resonance is insufficiently accurate to enable us to observe any significant differences. The hot electron injection experiments on transistors, consistent with other authors, indicate that, for the limited number of measurements we have made, the transistor ageing resulting from the generation of interface states is significantly reduced for devices annealed in the D containing gas as compared to those annealed in the H containing gas. The origins of some potential differences in annealing behaviour between the SiO2/Si structures and the 0.25 μm transistors are suggested.