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Source of surface defects in silicon carbide epitaxial files and their elimination method

碳化硅外延锉表面缺陷的来源及消除方法

基本信息

批准号：
16560009
负责人：
OKADA Tatsuya
金额：
$ 2.66万
依托单位：
The University of Tokushima
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2007
项目状态：
已结题

项目摘要

Silicon carbide (SIC) has been attracting much attention because of its application to power devices exhibiting superior performance to conventional Si-based ones. large-area epitaxial films of high quality are essential for the fabrication of kV-class high-power SiC devices. However ; at the present stage, imperfections in epitaxial films including surface defects impose a limitation on high-yield production of such devices. When formed, some types of surface defect deteriorate device performance by lowering the breakdown voltage of p-n junctions by 20 to 40%. The major objectives of the present study are to investigate the source of surface defects at the substrate/epifilm interface by plan-view transmission electron microscopy (TEM) and to find a technique to eliminate crystallographic defects accompanying surface defects.We were successful in preparing plan-view TEM samples which contain the substrate/epifilm interface in the thinned area by removing almost the entire epifilm with … More reactive plasma-etching prior to the conventional ion-thinning from the substrate side. The source of surface defects was composed of an inclusion and partial dislocations. Energy dispersive X-ray (EDX) spectroscopy and micro-Raman analysis unraveled that the inclusions were very small particles of zirronia (ZrO_2). The thermal insulator in the chemical vapor deposition (CVD) furnace is the most suspicious origin of ZrO_2 particles. The ZrO_2 particles which fell onto the SiC substrate surface and were ncorporated into the epifilm may have acted as the source of partial dislocations, which resulted in the formation of surface defects.We propose that phase change induced by irradiation of ultra-short laser pulses may be applied to the elimination of defects in SiC epitaxial films. When femtosecond laser pulses are irradiated on the surface of SiC, periodic surface microstructures referred to as ripples are formed. In order to study the cross-sectional microstructures of ripples, we carried out TEM studies with particular attention on the crystal structure underlying ripples. A continuous amorphous layer approximately 10 to 50 nm thick was found to cover the topmost region of ripples. Less

碳化硅（SiC）因其在功率器件中的应用而受到广泛关注，其性能上级传统的硅基材料。高质量的大面积外延膜对于制造kV级高功率SiC器件是必不可少的。然;在现阶段，包括表面缺陷的外延膜中的缺陷限制了这种器件的高产率生产。当形成时，某些类型的表面缺陷通过将p-n结的击穿电压降低20至40%而使器件性能劣化。本研究的主要目的是通过平面透射电子显微镜（TEM）研究衬底/外延膜界面处的表面缺陷来源，并找到一种消除伴随表面缺陷的晶体缺陷的技术。我们成功地制备了平面TEM样品，该样品在减薄区域包含几乎整个外延膜，并在减薄区域包含衬底/外延膜界面。我们还成功地制备了透射电子显微镜样品，该样品在减薄区域包含衬底/外延膜界面，并在减薄区域包含衬底/外延膜界面。我们还成功地制备了透射电子显微镜样品，该样品在减薄区域包含衬底/外延膜界面，并在减薄区域包含衬底/外延膜界面，并在减薄区域包含衬底/外延膜界面，并在减薄区域包含衬底/外延膜界面，并在减薄区域包含衬底/外延膜界面 ...更多信息在从衬底侧进行常规离子减薄之前进行反应性等离子体蚀刻。表面缺陷源由夹杂物和部分位错组成。能量色散X射线（EDX）光谱和显微拉曼光谱分析表明，夹杂物是非常小的氧化锆（ZrO_2）颗粒。化学气相沉积（CVD）炉中的绝热层是ZrO_2颗粒最可疑的来源。ZrO_2颗粒落在SiC衬底表面并结合到外延膜中，可能是部分位错的来源，导致了表面缺陷的形成，我们认为超短激光脉冲辐照诱导的相变可以用来消除SiC外延膜中的缺陷。当飞秒激光脉冲照射在SiC表面时，形成被称为波纹的周期性表面微结构。为了研究波纹的横截面微观结构，我们进行了TEM研究，特别注意波纹下的晶体结构。一个连续的非晶层约10至50纳米厚的被发现覆盖的波纹的最高区域。少