Papers by Keyword: Growth Rate

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Authors: James D. Oliver, Brian H. Ponczak
Abstract: A series of designed experiments have been conducted over a period of years in a multiwafer, planetary rotation, epitaxial reactor to quantify the effects of various epitaxial growth process parameters on the resulting SiC epitaxial layers. This paper summarizes the results obtained through statistically designed experiments varying process parameters and their resultant effect on the layer thickness, carrier concentration and the variability of these parameters wafer-to-wafer, and within a wafer.
Authors: Yong Xiang Zhao, Bing Yang, Wei Hua Zhang
Abstract: A series of uniaxial-compression tests were conducted on some representative brittle rock specimens, such as granite, marble and dolerite. A multi-channel, high-speed AE signal acquiring and analyzing system was employed to acquire and record the characteristics of AE events and demonstrate the temporal and spatial distribution of these events during the rupture-brewing process. The test result showed that in the primary stage, many low amplitude AE events were developed rapidly and distributed randomly throughout the entire specimens. In the second stage, the number of AE increased much slower than that in the first stage, while the amplitude of most AE events became greater. Contrarily to the primary stage, AE events clustered in the middle area of the specimen and distributed vertically conformed to the orientation of compression. The most distinct characteristic of this stage was a vacant gap formed approximately in the central part of the specimen. In the last stage, the number of AE events increased sharply and their magnitude increased accordingly. The final failure location coincidently inhabited the aforementioned gap. The main conclusion is that most macrocracks are developed from the surrounding microcracks existed earlier and their positions occupy the earlier formed gaps, and the AE activity usually becomes quite acute before the main rupture occurs.
Authors: Martin Seiss, Thierry Ouisse, Didier Chaussende
Abstract: The growth process of silicon carbide crystals by physical vapor transport (PVT) on Si-face (0001) on-axis 6H-SiC substrates was analyzed. The growth rate was observed to be almost inversely proportional to the deposition pressure (R ∝ p-1) meaning that the growth rate is not limited by the number of growth spirals but by the vapor phase transport of the depositing species from the source to the sample surface. Analysis of the spiral step width shows an inverse square root dependence on the growth rate (y0 ∝ R-½). This experimental result is in accordance with the Burton, Cabrera and Frank theory and hence it can be concluded that there is no back-stress effect present.
Authors: Hidekazu Tsuchida, Isaho Kamata, Masahiko Ito, Tetsuya Miyazawa, Hideyuki Uehigashi, Keisuke Fukada, Hiroaki Fujibayashi, Masami Naitou, Kazukuni Hara, Hitoshi Osawa, Toshikazu Sugiura, Takahiro Kozawa
Abstract: This paper reports on recent advances in 4H-SiC epitaxial growth toward high-throughput production of high-quality and uniform 150 mm-diameter 4H-SiC epilayers by enhancing of growth rates, improving uniformity and reducing defect densities. A vertical single-wafer type SiC epitaxial reactor is employed and high-speed wafer rotation is confirmed as effective, not only for enhancing growth rates without increasing the source gas supply but also improving thickness and doping uniformities. The current levels of reducing particle-induced defects, in-grown stacking faults, basal plane dislocations and the Z1/2 center (carbon vacancies) are reviewed.
Authors: S.Yu. Karpov, A.V. Kulik, M.S. Ramm, E.N. Mokhov, A.D. Roenkov, Yu.A. Vodakov, Yuri N. Makarov
Authors: Jung Doo Seo, Joon Ho An, Jung Gon Kim, Jung Kyu Kim, Myung Ok Kyun, Won Jae Lee, Il Soo Kim, Byoung Chul Shin, Kap Ryeol Ku
Abstract: SiC single crystal ingots were prepared onto different seed material using sublimation PVT techniques and then their crystal quality was systematically compared. In this study, the conventional SiC seed material and the new SiC seed material with an inserted SiC epitaxial layer on a seed surface were used as a seed for SiC bulk growth. The inserted epitaxial layer was grown by a sublimation epitaxy method called the CST with a low growth rate of 2μm/h. N-type 2”-SiC single crystals exhibiting the polytype of 6H-SiC were successfully fabricated and carrier concentration levels of below 1017/cm3 were determined from the absorption spectrum and Hall measurements. The slightly higher growth rate and carrier concentration were obtained in SiC single crystal ingot grown on new SiC seed materials with the inserted epitaxial layer on the seed surface, maintaining the high quality.
Authors: Hideyuki Uehigashi, Keisuke Fukada, Masahiko Ito, Isaho Kamata, Hiroaki Fujibayashi, Masami Naitou, Kazukuni Hara, Hitoshi Osawa, Takahiro Kozawa, Hidekazu Tsuchida
Abstract: We have developed a single-wafer vertical epitaxial reactor which realizes high-throughput production of 4H-SiC epitaxial layer (epilayer) with a high growth rate [1,2]. In this paper, in order to evaluate the crystalline defects which can affect the characteristics of devices, we investigated the formation of variety of in-grown stacking faults (SFs) in detail. Synchrotron X-ray topography, photoluminescence (PL) and transmission electron microscopy are employed to analyze the SFs and the origins of the SF formation are discussed. The result in reducing in-grown SFs in fast epitaxial growth is also shown.
Authors: Eugene Y. Tupitsyn, Alexander Galyukov, Maxim V. Bogdanov, Alexey Kulik, Mark S. Ramm, Yuri N. Makarov, Tangali S. Sudarshan
Abstract: In this work the problem of growth rate decaying during growth is considered. A new design and growth profiles are suggested in order to reduce deviations of growth parameters during the process of growth.
Authors: Wei Wang, Nan Chun Chen, Quan Hong Li, Xin Tang
Abstract: According to the conditions of preparation of mullite composites by open-system hydrothermal crystallization method, surface energies of mullite crystal were calculated by the first principle plane pseudo-potential. Growth habit plane of mullite composites was also discussed and analyzed. The calculation results demonstrate that surface energies of (001), (010), (100), (210) and (120) of mullite crystal are 0.337KeV•nm-2, 0.029KeV•nm-2, 0.027KeV•nm-2, 0.032KeV•nm-2, 0.037KeV•nm-2, respectively. That is to say, the surface energies of mullite crystal follow the order of (001) >> (210) > (120) > (100) > (010). It is also found that E(001) is much larger than others. According to Curie-Wulff principle, growth rate of crystal face is directly proportional to its surface energy, which shows that growth rate of mullite crystal in (001) direction is the fastest and mullite crystal is favorable for one-dimensional growth to columnar.
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