bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Interfacial Roughness in Semiconductor Heterostructures by X-Ray Reflectivity
Authors: Krol A. , Sher C. J. , Resat H. , Woronick S. C. , Ng W. , Kao Y. H. , Chang L. L. , Hong J. M. 
Published: March 2011

ABSTRACTThe reflection of monochromatic x-rays by a layered heterostructure can be utilized as a nondestructive probe to obtain information on the interfacial roughness in the material. Interference between x-rays reflected from the top surface and the interfaces can give rise to pronounced oscillations in the reflectivity as a function of the grazing incidence angle. We have made use of this technique to investigate the interfacial roughness in semiconductor heterostructures grown by molecular beam epitaxy.
Forces on Dislocations in Multilayer Structures
Authors: Kamat Somir V. , Hirth J. P. , Carnahan B. 
Published: March 2011

ABSTRACTIn multilayer structures, dislocation forces that arise from coherency strains are well understood in both the isotropic and anisotropic elastic cases. Image forces produced by elastic inhomogeneity have also been developed for single layers surrounded by extended phases. Image forces for the multilayers are shown to reduce to the simpler single embedded layer case to a good approximation. Image forces are shown to lead to a “stand-off” position of interface dislocations from the interface, with several implications for the properties of multilayer structures.
Structural Perfection of in GaAs/InP Superlattices Grown by Gas Source Molecular Beam Epitaxy: A High-Resolution X-Ray Diffraction Study
Authors: Vandenberg J. M. , Panish M. B. , Hamm R. A. 
Published: March 2011

ABSTRACTHigh-resolution X-ray diffraction (HRXRD) studies have been cardied out to determine the structural perfection and periodicity for a number of high-quality InGaAsfInP superlattices grown by gas source molecular beam epitaxy. X-ray scans were carried out with a compact four-crystal monochromator resulting in a resolution of one molecular layer (∼3,Å), which enables one to observe very small variations in the periodic structure. Sharp and strong higher-order satellite reflections in the XRD profiles were observed indicating smooth interfaces with well-defined modulated structures. Excellent computer simulated fits of the X-ray satellite pattern could be generated based on a kinematical XRD step model which assumes ideally sharp interfaces, and periodic structural parameters such as the strain in the well could be extracted. Our results3 demonstrate that HRXRD in conjunction with the kinematical step model is a very sensitive method to assess periodic structural modifications in superlattices as a result of the precise growth conditions in the gas source MBE system.
From Electronic Structure To Thermodynamics
Authors: Bachelet Giovanni B. 
Published: March 2011

ABSTRACTA simple way to extend the remarkable results of Density Functional calculations to finite-temperature properties of materials is the quasi-harmonic theory of Lattice Dynamics. In this framework a thermodynamically consistent theory needs the complete phonon spectrum for a large periodic system (30–100 atoms/cell) at many different volumes, which poses severe practical limitations. In this paper I present the application to a semiconducting system of a method recently proposed by Bachelet and De Lorenzi to overcome these limitations. Based on low-temperature Molecular-Dynamics trajectories (now possible from first principles for semiconducting systems according to the method of Car and Parrinello), the method is shown to provide accurate dynamical matrices for an 8-atom silicon supercell. Such a successful, preliminary test, together with the fact that for larger and/or lower-symmetry systems the computational effort required by the “trajectory approach” is lower than traditional frozen-phonon or force-constant techniques, suggests its use in the determination of dynamical matrices of larger defect or amorphous systems, and thus in the study of their thermodynamics from first principles.
Electrical Characterisation of Shallow Pre-Amorphised +n junctions in silicon
Authors: Brotherton S. D. , Ayres J. R. , Clegg J. B. , Goldsmith B. J. 
Published: March 2011

ABSTRACTAn examination of Si+ pre-amorphised p+n structures as a function of Si+ implantation energy and solid phase epitaxial regrowth temperature has revealed three different classes of defect all of which may influence the characteristics of the junction. They are point defects responsible for high concentrations of deep level donors, and interstitial dislocation loops both causing leakage current degradation, and excess silicon interstitials leading to enhanced junction movement.
Effects of Carbon Concentration Upon Oxygen Precipitation in Cz Si
Authors: Hahn S. , Arst M. , Ritz K. N. , Shatas S. , Stein H. J. , Rek Z. U. , Tiller W. A. 
Published: March 2011

ABSTRACTEffects of high carbon concentration upon oxygen precipitate formation in Cz silicon have been investigated by combining various furnace and rapid thermal annneals. Even though oxide precipitate density increases with increasing carbon levels, Cs, synchrotron radiation section topographs of processed high carbon content wafers (Cs ∼ 4ppma) exhibit Pendellosung fringes, indicating a strain free bulk state. Our optical microscopic data have also shown very few defect etch features inside the bulk. A model based upon a direct coupling of both SiO2 and Si-C complex formation reactions is used to explain rather unique oxygen precipitation characteristics in the high carbon content Cz Si materials.
Microscopic Analysis of the Behavior of Interstitial and Precipitated Oxygen During Intrinsic Gettering in Si
Authors: Sun Qing , Lagowski J. , Gatos H. C. 
Published: March 2011

ABSTRACTWe have used FTIR spectrum processing to analyze the behavior of interstitial and precipitated oxygen during the intrinsic gettering process. The kinetics of precipitation and the microscopic growth characteristics of precipitates were compared with a theoretical model based on diffusion controlled precipitation process. The annealing time dependence of precipitate size has been found to follow the relation of r = tn with n = 0.7.
Oxygen Aggregation Phenomena in Silicon
Authors: Newman Ronald C. 
Published: March 2011

ABSTRACTOxygen precipitation in Czochralski silicon heated in the range 400–1050°C is reviewed. For T≥525° C, Si02 particles form at the normal diffusion rate and there is generation of self-interstitials. At the lower temperatures, the existence of the interfacial energy causes an apparent increase in the solid solubility as the agglomerates become very small: at 525° C they contain only an estimated 20–50 atoms. A critical analysis s then presented of possible oxygen aggregation reactions at even lower temperatures when thermal donors are generated. It is not yet possible to reconcile the kinetics of these two processes, even if self-interstitials and/or vacancy reactions are included. There is no evidence for enhanced diffusion of isolated oxygen atoms except as a transient process occurring during the relaxation of stress-induced dichroism. Oxygen aggregation at 450 ° C appears to be limited by the formation of dimers with an activation energy of 2.5eV, while thermal donors form with an activation energy of 1.7eV.
Effects in Silicon Explained by Atomic Hydrogen
Authors: Schnegg A. , Prigge H. , Grundner M. , Hahn P. O. , Jacob H. 
Published: March 2011

ABSTRACTThe chemomechanical polishing mechanism is described as a corrosive attack of water forming Si-H and Si-OH groups. By adding ammonia or amines to the slurry we observe an irlfease of the resistivity corresponding to a neutralization of up to 1 × 1017 acceptor atoms cm−3 in the case of p-type silicon, whereas n-type silicon can show a slight reduction in resistivity due to the neutralization of the residual acceptor concentration.SIMS measurements show the presence of hydrogen in the bulk. Using deuterium instead of hydrogen, a correlation could be established between the deuterium content of the wafer, measured by the effusion technique, and the degree of the acceptor compensation.As can be shown by resistivity and C/V-measurements, under the conditions of polishing the supposed inactivator hydrogen migrates to a distance finally corresponding to the thickness of a wafer. This is contrary to the comm on method of plasma treatment, where a damaged silicon layer is supposed to act as a barrier to the hydrogen diffusion. Differences in the IR spectra can be explained this way.Crystal imperfections in the bulk and on the surface influences the migration of hydrogen essentially.
Carrier Removal in n+ GaAs:Si by Proton Implantation. a Spectroscopic Study
Authors: Pajot B. , Chevallier J. , Chaumont A. , Azoulay R. 
Published: March 2011

ABSTRACTProtons and deuterons have been implanted in n+ GaAs:Si epilayers. Localized vibrational modes (LVM's) associated to H- and D-related defects are observed in the as-implanted samples and they account presumably for the carrier removal in the compensated region, but a small concentration of Si-H passivating centers is already present. LVM spectroscopy shows that after a 200° C annealing, passivation predominates over compensation while a 400° C annealing extends partial passivation throughout the layer.
Endor Spectroscopy on Deep Level Defects in Gaas
Authors: Spaeth J.-M. , Gorger A. , Hofmann D. M. , Meyer B. K. 
Published: March 2011

ABSTRACTWith optically detected electron spin resonance (ODESR) and electron nuclear double resonance (ODENDOR) the following deep level defects in s.i. LEC-grown GaAs were investigated: EL2 defects in undoped GaAs and VGa2+ and VGa3+ defects in V-doped GaAs. This paper summarizes the major results: (i) the double donor defect EL2 in an (AsGa-Asi+) pair defect, which is distributed rather homogeneously across an as-grown wafer. After inverted thermal conversion treatment it is destroyed, and 3 new paramagnetic defects appear. EL2 is recovered after annealing at ca. 800 °C, while the 3 new defects disappear. (ii) A new ESR spectrum due to VGa2+ was measured. It is shown for the first time for a 3dn impurity in semiconductors that VGa3+(3d3)is in a low spin state (S = 1/2) in accordance with recent theoretical predictions. A deep level defect at Ev + (0.2–0.4) eV is discovered, which is probably the defect needed for explaining the s.i. properties of V-doped GaAs.
Space and Time Resolved Photoluminescence of Defects at Dislocations in In-Alloyed GaAs Substrate Material
Authors: Johnson Matthew B. , Hunter A. T. , McGill T. C. 
Published: March 2011

ABSTRACTWe report a study of dislocations in In-alloyed GaAs substrate material using space and time resolved photoluminescence (PL). PL intensity maps show that an isolated dislocation cluster is in the center of a dark region with a 50μm radius surrounded by a bright region with an outer radius of 150μm. Lifetime measurements were made in the bright and dark regions. Values as long as 3.5 ns and as short as 250 psec were observed in adjacent bright and dark regions. These measurements indicate that the PL intensity contrast is explained by lifetime variations in these features. This supports the view that the dislocation cluster acts as a source and sink for defects which govern the lifetime in the surrounding material. Temperature dependence of the lifetime indicates two different defects may be involved. Both of these produce deep levels, neither one of which is EL2. A surface passivation technique is used to show that surface recombination is not important to the PL intensity contrast.
Vacancy Diffusion at Polysilicon Encapsulated GaAs Surfaces
Authors: Kavanagh K. L. , Magee C. W. , Sheets J. 
Published: March 2011

ABSTRACTThe diffusivity of Si and P in GaAs encapsulated with heavily-doped polysilicon (poly-Si) is correlated to the flux of Ga and As diffusing from the substrate into the encapsulant. A model based on the diffusion of vacancies into the GaAs is proposed and used to simulate the data.
Site Occupation of Implanted Te in Gaas As a Function of Implantation Dose
Authors: Langouche G. , Schroyen D. , Bemelmans H. , Van Rossum M. , Deraedt W. , de Potter M. 
Published: March 2011

ABSTRACTTe atoms were implanted in GaAs with doses ranging from 1013 to 1016 atoms/cm2, and annealed with the rapid thermal annealing technique. The samples were studied by Mössbauer Spectroscopy, Rutherford Backscattering Spectroscopy – Channeling, and the Van der Pauw-method. While at the lowest implantation dose an unperturbed substitutional site is observed at all annealing temperatures, at the highest implantation dose a strong deviation from a central position in an unperturbed configuration is observed at all temperatures. At the intermediate doses a high degree of substitutionality is observed between annealing temperatures of 200°C and 500°C only.
Pressure-dependent DLTS Experiments on Si-DOPED AlGaAs
Authors: Farmer John W. , Hjalmarson Harold P. , Samara G. A. 
Published: March 2011

ABSTRACTPressure dependent Deep Level Transient Spectroscopy (DLTS) experiments are used to measure the properties of the deep donors (DX-centers) responsible for the persistent photoconductivity effect in Si-doped AlGaAs. The sample dependence of the DLTS spectra shows evidence for a defect complex involved in the DX-center.
Identification of Interstitial Carbon Related Defects in Silicon
Authors: Benton J. L. , Asom M. T. , Sauer R. , Kimerling L. C. 
Published: March 2011

ABSTRACTDLTS measurements are used to detect and identify the interstitial related defects in n-type silicon. The materials dependences of the reactions of the [E(0.12), H(O.27)], [ME(0.30), ME(0.29), ME(0.23), ME(0.21)], ]ME(0.10), ME(0.17)] and [H(0.36)] spectral features lead to their identification as representing the two charge states of Ci, the multistable configurations of Ps-Ci, the bistable Cs-Sii-Cs, and the Ci-Oi defects, respectively. The branching ratios for the reactions of interstitial carbon with the impurities are given.
Photoassisted Deposition of Silicon Dioxide from Silane and Nitrogen Dioxide
Authors: Marks Jeffrey , Bowman Robert C. , Robertson Ruby E. 
Published: March 2011

AbstractThree new reactions for depositing silicon dioxide at low temperatures using vacuum ultraviolet and ultraviolet radiation to initiate a reaction between silane and nitrogen dioxide have been developed. The optical and electrical properties of these films are reported. The effect of ion implantation on the infrared spectra of oxides grown by vacuum ultraviolet irradiation is also presented.
The Electrical Properties of Silicon Oxide Deposited By Remote Plasma Enhanced Chemical Vapor Deposition (Rpecvd).
Authors: Kim Sang S. , Tsu D. V. , Lucovsky G. 
Published: March 2011

AbstractWe have constructed an Ultra High Vacuum (UHV) multichamber system and have deposited ‘gate quality’ silicon dioxide by the remote plasma enhanced chemical vapor deposition (Remote PECVD) process at low substrate temperatures (Ts ≤400 °C). Native oxides and other surface contaminants are removed under ultra high vacuum (UHV) conditions and the character of the semiconductor surface is determined prior to film deposition using in-situ Reflection High Energy Electron Defraction (RHEED). Measurents made on MOS structures of capacitance-voltage, current-voltage, field break-down, hysteresis, and mobile ion drift indicate that these films are ‘comparable’ to thermally (Ts >1100 °C) grown oxides. The structural properties of the films arg studied by ir spectroscopy and ellipsometry.
The Chemical Interface of Microwave Plasma Deposited SiO2 Films
Authors: Parks C. C. , Robinson B. , Leary H. J. , Childs K. D. , Coyle G. J. 
Published: March 2011

AbstractThe bulk and interfacial chemistry of a microwave plasma deposited SiO2 film has been studied. The SiO2 was deposited on single crystal Si<100> using a plasma enhanced chemical vapor deposition (PECVD) technique. The deposition was accomplished by injecting 2% SiH4 in helium downstream of a N20 microwave-generated discharge. Materials properties of these films were characterized using a combination of surface analytical techniques: Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectroscopy (SIMS). The width of the interface was determined by AES-depth profiling to be less than 5.0 nm. Normal and grazing-angle XPS measurements indicated the presence of unique N and Si chemical species at the SiO2/Si interface. The SIMS data confirmed the presence of interfacial and bulk nitrogen, as well as detecting the presence of hydrogen and fluorine in the bulk oxide. The relationship between the analytical results and electrical data, obtained using MOS structures fabricated from the deposited oxide, will be discussed.
Thermal xidation of silicon in dry oxygen: - the role of crystallographic orientation -
Authors: Taniguchi K. , Hamaguchi C. , Kobayashit K. , Hirayamat M. 
Published: March 2011

AbstractBased upon the linear-parabolic growth model of silicon oxidation, accurate kinetic rate constants are determined for various crystallographic orientation wafers in the 900 −1100°C range. The parabolic rate constant is independent of substrate orientation above 1000 °C, while, at 900°C, it depends on the orientation of the underlying substrate. The behavior of the parabolic rate constant at low temperature can be explained by accounting for Si-O bond-breaking due to stress during the oxide growth. The linear rate constant is observed to depend on the crystallographic orientation of the silicon surface in all temperature range. The orientation dependence of the linear rate constant is explained by both strain relaxation of the oxide film and areal atomic density of silicon at the silicon/oxide interface.
Structural Inhomogeneities Of SiO2 Quartz Gláss
Authors: Bochyński Zenon 
Published: March 2011

AbstractTill now the only effective method of direct determination of structural parameters has been X-ray diffraction structural analysis. This method applied to crystalline materials has proved a great success and applied to noncrystalline substances like for example inorganic glasses, is becoming more and more successful.Beginning with the W. Ostwald proposition /1913/ carried out by W. Friedrich /1913/ and P. Debye /1915/ through the papers by B.E. Warren et al. /1934–1942/ or by E.A. Poray-Koshits et al. /1934–1942/ till the most recently published papers devoted to structural studies of noncrystalline /amorphous/ materials we follow a significant progress in technology and methodology of these studies.The resulting significant improvement to the accuracy of results yields much more accurate structural models of non-crystalline materials.
Formation and Passivation of New Paramagnetic Defects Associated With Thermal Oxides On Silicon
Authors: Brower Keith L. 
Published: March 2011

AbstractA new spin resonance spectrum has been observed with electron paramagnetic resonance in thermal oxides grown on (111) silicon. Our analysis indicates that this new spectrum consists of two isotropic resonances. One resonance has a g-value of 2.0026 and a linewidth (FWHM) of 1.2 G (labeled SL8); the other resonance has a g-value of 2.0029 and a linewidth (FWHM) of 5 G (labeled SL9). These spectra might be due to impurity contamination resulting from the oxidation process and associated with defects at interior surfaces. The SL8 resonance in particular appears to be located within the as-grown thermal oxide. The effects of 60Co gamma irradiation and annealing in either hydrogen or ammonia on these spectra are also presented in this paper.
Submicron Roughness Determination at the Si-SiO2 Interface and Correlations to Prccessing Steps and Electronic Properties
Authors: Hahn Peter O. , Lampert I. , Schnegg A. 
Published: March 2011

AbstractA newly developed optical surface characterization technique using the diffuse scattered light of two laser beams will be presented. The method determines root-mean-square roughness values (RMS) of surfaces down to 1 Å and corresponding correlation lengths in the submicron area.
Oxidation Kinetics of Ge+-Ion Implanted Si
Authors: Holland O. W. , White C. W. , Fathy D. 
Published: March 2011

AbstractKinetic data are provided for oxidation of Ge+-ion implanted Si over a range of temperature and oxidation ambient. Oxidation rates were enhanced in implanted Si and, over most of the range studied, found to be consistent with a modified reaction at the oxide/Si interface. However, this reaction is shown to be more complex than in virgin Si and could not be represented by a single activation energy. An anomalous behavior is exhibited at low-temperature for steam oxidation. This behavior is characterized and the mechanisms which are responsible are discussed.
Scanning Tunneling Microscopy Studies of the Initial Stages of Thin Film Growth: the Role of the Surface Dangling Bonds
Authors: Avouris Ph. , Wolkow R. , Bozso F. , Hamers R. J. 
Published: March 2011

AbstractWe present STM and photoemission studies of the reactions of Si(100)-(2×1) and Si(111)–(7×7) with NH3. STM allows us to image the occupied and unoccupied states of the reacting systems and to obtain electronic spectra with atomic lateral resolution. Thus, for the first time, a surface chemical reaction can be probed at the atomic level. We find that both surfaces are reactive even at 100K. However, both the extent of the reaction and the reaction products at 300K are different on the two surfaces. STM also shows that while surface dangling bonds are essential for low-temperature reactivity, not all triplycoordinated Si sites are chemically equivalent. On the 7×7 surface the rest-atoms are more reactive than center-adatoms which, in turn, are more reactive than corner-adatoms.
Coupled Diffusion of Ion-Implanted Arsenic in Silicon Dioxide
Authors: Lee S.- Tong , Lavine J. P. , Fellinger P. R. 
Published: March 2011

AbstractA fast diffusing As species in ion-implanted SiO2 in N2 annealing ambient has been observed for the first time. This As diffuses 20X faster at 1100°C than the slow As found in oxidizing ambients. The activation energy of diffusion of this fast As is 0.71 eV, in sharp contrast to 4.3 and 4.0 eV for the slow As in O2 and O2 /H2O, respectively. The fast species is believed to be As occupying either the O-site or interstitial site in the SiO2 network. By assuming a fast and a slow species coupled together by transitions, we were able to obtain reasonable fits to the SINS diffusion profiles.
Grain Growth in Polycrystalline Silicon Films
Authors: Thompson C. V. 
Published: March 2011

ABSTRACTExperimental observations of recrystallization, normal grain growth and secondary grain growth in silicon films are reviewed. Normal grain growth leads to grain sizes which are approximately equal to the film thickness. Secondary grain growth can lead to larger grains with restricted crystallographic textures. These procesess are affected by the as-deposited or as-crystallized grain structures and orientations. The rate of grain growth has been shown to be higher in phosphorous or arsenic doped films. Ion bombardment, oxidation, and interactions with silicides also lead to increased grain growth rates. Grain growth enhancement has been related to increased point defect concentrations or dopant redistribution.