The Experts below are selected from a list of 21330 Experts worldwide ranked by ideXlab platform
W Wijaranakula - One of the best experts on this subject based on the ideXlab platform.
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a real time simulation of point defect reactions near the solid and melt interface of a 200 mm diameter czochralski silicon Crystal
Journal of The Electrochemical Society, 1993Co-Authors: W WijaranakulaAbstract:A real-time simulation of the point-defect reactions near the solid and melt interface of a 200 mm diam Czochralski silicon Crystal was performed. The results from the thermal stress calculation accounting for the temperature dependence of the elastic modulus of silicon indicate that the thermal stresses in the vicinity near the solid and melt interface are far above the silicon yield strength. Therefore, it is suggested that the effect of thermal stresses on the point defect reactions in a Growing Crystal is negligible. In this work, the Crystal cooling conditions are found to have a significant impact on the point defect reactions
Jan Vanhellemont - One of the best experts on this subject based on the ideXlab platform.
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intrinsic point defect incorporation in silicon single Crystals grown from a melt revisited
Journal of Applied Physics, 2011Co-Authors: Jan VanhellemontAbstract:The so-called Voronkov criterion states that the dominant intrinsic point defect in a silicon single Crystal grown from a melt is determined by the ratio of pulling speed over temperature gradient near the melt/solid interface. Above a critical value of this ratio, the Crystal is vacancy-rich, while for a ratio below this value, the Crystal is interstitial-rich. Applying the Voronkov criterion implies, however, intrinsic point defect diffusivities and/or thermal equilibrium concentrations that can differ strongly from those experimentally determined using self- and metal-diffusion experiments. Furthermore, for a given hot zone, Crystal diameter, and length, the thermal gradient itself at the melt/solid interface is a function of the pulling speed, so that the criterion in principle can be replaced by one for the thermal gradient only. There is also experimental evidence, based on Crystal detaching experiments, that the Growing Crystal is always vacancy-rich at the solid/melt interface. In the present pape...
Brian Skromme - One of the best experts on this subject based on the ideXlab platform.
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intersecting basal plane and prismatic stacking fault structures and their formation mechanisms in gan
Journal of Applied Physics, 2005Co-Authors: X Huang, Michael Dudley, B Wagner, R F Davis, Lijun Wu, Eli Sutter, Brian SkrommeAbstract:A systematic study of intersecting planar boundary structures observed in a GaN epifilm grown on a vicinal 6H-SiC substrate (offcut towards [12¯10]) with an AlN buffer is presented. These structures are shown to comprise stacking faults that fold back and forth from the basal plane [I1 basal plane stacking faults (BSFs)] to the prismatic plane [prismatic stacking faults (PSFs)]. The PSFs, with fault vector 12⟨101¯1⟩ nucleate at steps on the substrate surface as a consequence of the different stacking sequences exposed on either side of the step. Once nucleated, PSFs intersecting the vertical step risers in the AlN buffer and eventually in the GaN film are replicated during the predominantly step-flow growth and propagate into the Growing Crystal. As a consequence of the different growth rates experienced on either side of the intersection of a PSF with a vertical step riser, the PSF may be redirected onto an equivalent {112¯0} plane, leaving an I1 BSF between the bottom of the redirected section of PSF an...
Michael Dudley - One of the best experts on this subject based on the ideXlab platform.
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volume production of high quality sic substrates and epitaxial layers defect trends and device applications
Journal of Crystal Growth, 2012Co-Authors: St G Muller, Michael Dudley, Edward K Sanchez, Darren Hansen, R D Drachev, G Y Chung, Bernd Thomas, Jie Zhang, Mark J Loboda, Huanhuan WangAbstract:Abstract We review the progress of silicon carbide (SiC) bulk growth by the sublimation method, highlighting recent advances at Dow Corning, which resulted in the commercial release of 100 mm n-type 4H-SiC wafers with median micropipe densities (MPD) in production wafers 0.1 cm − 2 and the demonstration of micropipe free material over a full 100 mm diameter. Investigations by Synchrotron White Beam X-ray Topography (SWBXRT) and molten KOH etch pit analysis of 100 mm wafers demonstrate threading screw dislocation densities 500 cm − 2 . Additional results indicate the positive impact of maintaining thermo-mechanical stress levels in the Growing Crystal below the critical resolved shear stress on reducing basal plane dislocation densities to values as low as ∼ 300 – 400 cm − 2 in 100 mm Crystals. We summarize the steps of systematic quality improvements on increasing wafer diameter, utilizing numerical simulations of the SiC growth system as a critical tool to guide this process. For the economical production of SiC epitaxy, a 10×100 mm wafer platform has been established in a warm-wall planetary chemical vapor deposition (CVD) reactor. The combined improvements in the epitaxy process, pre-epi wafer surface preparation and the underlying substrate quality itself have led to a reduction of the device killer defect density from 8 cm −2 to 1.5 cm −2 on a volume product like 100 mm 4° off-axis 6.5 μ m epi-wafers. Dow Corning production epi-wafers routinely show Schottky diode yields above 90% at a die size of 2 mm×2 mm. Additionally, 50 – 100 μ m thick epitaxy on 76 mm 4° off-axis wafers with morphological defect densities of 2–6 cm −2 , a surface roughness (RMS) ≤ 1 nm as measured by atomic force microscopy (AFM), and carrier lifetimes consistently in the range of 2 – 3 μ s has been demonstrated.
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intersecting basal plane and prismatic stacking fault structures and their formation mechanisms in gan
Journal of Applied Physics, 2005Co-Authors: X Huang, Michael Dudley, B Wagner, R F Davis, Lijun Wu, Eli Sutter, Brian SkrommeAbstract:A systematic study of intersecting planar boundary structures observed in a GaN epifilm grown on a vicinal 6H-SiC substrate (offcut towards [12¯10]) with an AlN buffer is presented. These structures are shown to comprise stacking faults that fold back and forth from the basal plane [I1 basal plane stacking faults (BSFs)] to the prismatic plane [prismatic stacking faults (PSFs)]. The PSFs, with fault vector 12⟨101¯1⟩ nucleate at steps on the substrate surface as a consequence of the different stacking sequences exposed on either side of the step. Once nucleated, PSFs intersecting the vertical step risers in the AlN buffer and eventually in the GaN film are replicated during the predominantly step-flow growth and propagate into the Growing Crystal. As a consequence of the different growth rates experienced on either side of the intersection of a PSF with a vertical step riser, the PSF may be redirected onto an equivalent {112¯0} plane, leaving an I1 BSF between the bottom of the redirected section of PSF an...
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vertical bridgman growth and characterization of large diameter single Crystal cdte
Journal of Crystal Growth, 1993Co-Authors: Louis G Casagrande, Michael Dudley, Don Di Marzio, M B Lee, David J Larson, Thomas FanningAbstract:We report on the growth of 64 mm diameter single Crystals of CdTe using a large-bore, high-thermal mass, multizone vertical Bridgman furnace. Ampoules are carefully prepared so that the probability of melt adhesion or spurious nucleation is reduced. The longitudinal thermal gradient imposed on the solidifying boule is less than 10°C cm −1 , and the hot and cold zone temperatures have been adjusted to reduce the interface curvature and the thermal stress on the Growing Crystal and the solidified portion of the boule. Post-solidification processing of the boule, including in-situ annealing and cooling rate, is designed to reduce the size of precipitates as well as residual strain. Wafers taken from the Crystals have been structurally and chemically characterized. We have been able to establish a correlation between features identified on high-quality surfaces of CdTe using synchrotron white beam topography (SWBT) and Nakagawa-etch-pit micrographs. We propose that SWBT can be utilized as an alternative to destructive etch pit analysis to characterize the {111}A surface defect structure, as well as to image the Nakagawa-inert {111}B surface or other surfaces of interest.
Robert J. Falster - One of the best experts on this subject based on the ideXlab platform.
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Intrinsic point defects and impurities in silicon Crystal growth
Journal of The Electrochemical Society, 2002Co-Authors: Vladimir V. Voronkov, Robert J. FalsterAbstract:28100 Novara 1, ItalyThe incorporation of intrinsic point defects into a Growing Crystal is affected by the presence of impurities that can react withvacancies and self-interstitials. The critical value of the ratio of the growth rate,V, to the axial temperature gradient, G, ~V/Gratio! that separates the interstitial growth mode from the vacancy growth mode, is shifted by impurities, and this effect can bedescribed by simple analytical expressions. Some impurities, such as oxygen, nitrogen, and hydrogen, trap vacancies and cause adownward shift in the critical V/G ratio ~and also a fast increase in the fraction of trapped vacancies, on lowering T!. Otherimpurities, like carbon, trap self-interstitials, and cause an upward shift in the criticalV/G ratio ~and also an increase in thefraction of impurity interstitials, on lowering T!. The impurities affect both the incorporation and agglomeration stages of micro-defect production.© 2002 The Electrochemical Society. @DOI: 10.1149/1.1435361# All rights reserved.Manuscript submitted June 12, 2001; revised manuscript received September 20, 2001. Available electronically January 29, 2002.
