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实现了熔融KOH进行SiC体单晶择优腐蚀估测缺陷密度的方法.本文报道了采用该技术对体SiC单晶缺陷密度估测的结果.腐蚀会在Si面形成六边形腐蚀坑,在C面形成圆形腐蚀坑.腐蚀速率和蚀坑形状与SiC生长工艺有关.对在高生长气流量下用PVT工艺制备的SiC样品,其刃位错、螺位错与微管密度分别为2.82×105,94和38cm-2;对在低生长气流量下用PVT工艺制备的SiC样品,其上述缺陷密度分别为9.34×105,2和29cm-2.结果表明:随着生长气体流量的增加,由于避免了N2掺杂,刃位错密度下降. 相似文献
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实现了熔融KOH进行SiC体单晶择优腐蚀估测缺陷密度的方法.本文报道了采用该技术对体SiC单晶缺陷密度估测的结果.腐蚀会在Si面形成六边形腐蚀坑,在C面形成圆形腐蚀坑.腐蚀速率和蚀坑形状与SiC生长工艺有关.对在高生长气流量下用PVT工艺制备的SiC样品,其刃位错、螺位错与微管密度分别为2.82×105,94和38cm-2;对在低生长气流量下用PVT工艺制备的SiC样品,其上述缺陷密度分别为9.34×105,2和29cm-2.结果表明:随着生长气体流量的增加,由于避免了N2掺杂,刃位错密度下降. 相似文献
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《电子工程师》2003,29(9):42-42
近日 ,中科院物理所陈小龙研究员领导的科研小组在碳化硅 (SiC)晶体生长方面取得了重大进展。他们在自行研制的高温生长炉上 ,解决了物理气相传输法中生长SiC晶体的一些关键物理化学问题 ,成功地生长出了直径为 2英寸的SiC晶体 ,其X -射线衍射摇摆曲线达到 2弧分 ,微管密度已少于 10 0个 /cm2 (10× 10mm2 样品 ) ,这些表征SiC晶体质量的重要参数指标超过了目前Cree公司的部分商品的指标 ,为SiC单晶的国产化奠定了基础。以碳化硅 (SiC)及GaN为代表的宽禁带材料 ,是继Si和GaAs之后的第三代半导体。与Si相比 ,SiC具有宽禁带 (Si的 2… 相似文献
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回顾了SiC单晶的发展历史,总结了目前的发展状况,同时介绍了SiC单晶生长所需要的温场和生长工艺,最后介绍了SiC单晶的加工技术. 通过模拟计算与具体实验相结合的方法,调整坩埚在系统中的位置及优化坩埚设计可以得到理想温场. 近平微凸的温场有利于晶体小面的扩展,进而有利于减少缺陷提高晶体的质量. 由于SiC硬度非常高,对单晶后续的加工造成很多困难,包括切割和磨抛. 研究发现利用金刚石线锯切割大尺寸SiC晶体,可以得到低翘曲度、低表面粗糙度的晶片;采用化学机械抛光法,可以有效地去除SiC表面的划痕和研磨引入的加工变质层,加工后的SiC晶片粗糙度可小于1nm. 相似文献
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In the present work the gas dynamics in the growth zone of SiC crystals is investigated. It is shown that the propagation of SiC vapour from the growth cavity walls towards the lids is effected by diffusion. On this basis the calculation of the concentration distribution of SiC vapour (n), the equilibrium vapour concentration (ns) and the supersaturation (α = [(n – ns)/ns] × 100%) in the crystal growth zone at different radial and axial gradients is carried out by solving the Laplace equation in cylindrical co-ordinates for a stationary case corresponding to the conditions of crystal growth. The results obtained are compared with the available experimental data, which gives the possibility of explaining some of the observed peculiarities during SiC crystal growth from the vapour phase by the sublimation method. 相似文献
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Interest in silicon carbide as a semiconductor suitable for fabricating devices operating under extreme conditions has increased
sharply in recent years. The main problem now lies in the mass production of silicon carbide single crystals with a low defect
density and high crosssectional uniformity of the properties. This study involves a numerical simulation of heat and mass
transfer processes during growth of SiC single crystals by the sublimation method. The results obtained make it possible to
trace the effect of the growth conditions on the temperature distribution and the distribution of the main components in the
vapor phase, as well as the radial profile of the rate of growth of a single crystal for different stages of growth process.
Fiz. Tekh. Poluprovodn. 31, 794–799 (July 1997) 相似文献
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Silicon carbide (SiC) is a promising wide bandgap semiconductor material particularly suitable for future high power devices operable at high temperatures (>200 °C), at high frequencies, and in harsh environments (chemical and radiation) due to its unique physical and crystallographic properties. The absence of SiC liquid phase, under easily achievable growth conditions of pressure and temperature has created unique challenges for crystal growers.This paper reviews the basics of bulk growth processes, including source sublimation, mass transport of the Si and C species to the growing seed and crystallization. The growth process is shown to be a self-congruent phenomenon where the mass transport of the vapor species and the heat dissipation at the surface of phase transformation are interrelated. This process results in reduction of the growth velocity as a function of crystal thickness. Major mechanisms of defect generation in the grown crystal are discussed. 相似文献
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在用SEM观察沿单晶生长方向切割掺V SiC晶片时,发现其二次电子像存在衬度。表现为先生长部分较明亮,后生长部分较暗淡,中间存在明显突变。在用PVT生长掺V SiC单晶时,SiC单晶中同时含有浅施主N和深受主杂质V是补偿半导体。从补偿半导体载流子浓度计算出发,建立了二次电子像衬度与载流子浓度的对应关系,很好解释了这一实验现象。结果表明,SiC单晶生长过程中随着浅施主N的减少,n型载流子的浓度逐步减少;当其浓度与V相当时,载流子浓度突变,可瞬间减少10个量级,此后又缓慢减少。正是这种载流子的突变引发了扫描电镜二次电子像衬度。 相似文献
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Brandon A. Aguirre David Zubia Rafael Ordonez Farhana Anwar Heber Prieto Carlos A. Sanchez Maria T. Salazar Alejandro. A. Pimentel Joseph R. Michael Xiaowang Zhou John C. Mcclure Gregory N. Nielson Jose L. Cruz-Campa 《Journal of Electronic Materials》2014,43(7):2651-2657
Selective-area deposition of CdTe on CdS via close-space sublimation is used to study the effect of window size (2 μm and 300 nm) on grain growth. The basic fabrication procedures for each of the layers (CdS, SiO2, and CdTe) and for achieving selective-area growth are presented. Selective-area growth of both micro- and nano-scale CdTe islands on CdS substrates using close-spaced sublimation is demonstrated. Scanning electron microscopy and electron backscatter diffraction microstructure analysis show that the micro-scale CdTe islands remain polycrystalline. However, when the island size is reduced to 300 nm, single crystal CdTe can be achieved within the windows. The CdTe grains were most often in the (101) orientation for both the micro- and nano-sized CdTe islands. 相似文献