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）一直引起了很多关注，因为它在电力设备上的应用与常规SI基于SI的功能具有出色的性能。高品质的大面积外延膜对于制造KV级高功率SIC设备至关重要。然而;在当前阶段，包括表面缺陷在内的外延膜中的瑕疵对此类设备的高收益产生施加了限制。形成时，某些类型的表面缺陷通过将P-N连接的故障电压降低20％至40％，从而检测到设备的性能。本研究的主要目的是通过计划视图传输电子显微镜（TEM）调查底物/Epifilm界面处的表面缺陷来源，并找到一种技术来消除表面缺陷的晶体缺陷的技术，我们成功地涉及sibstrate/Epifilm Interfifif的plan视图中，我们成功地将splate/Epifilm Interme iptifif informe-Eperme-exififif iptififem恢复……从基板侧进行常规离子粉化之前。表面缺陷的来源由包含和部分脱位组成。能量色散X射线（EDX）光谱和微拉曼分析揭示了夹杂物是Zirronia的很小颗粒（ZRO_2）。化学蒸气沉积（CVD）炉中的热绝缘子是Zro_2颗粒的最可疑起源。落在SIC底物表面上并将其纳入Epifilm的ZRO_2颗粒可能是部分位错的来源，这导致了表面缺陷的形成。我们提出，通过超短脉冲激光脉冲的辐射引起的相变，可以应用于消除Sic e eSic e eSiC epitaxial sims sic sic epitaxial hims sic sic epitaxial hims sic sic epitaxial sims siss sicsial siss siss。当飞秒激光脉冲在SIC的表面受辐照时，形成了称为波纹的周期性表面微观结构。为了研究涟漪的横截面微观结构，我们特别关注了纹波背后的晶体结构，进行了TEM研究。发现一个约10至50 nm厚的连续无定形层覆盖了最高的波纹区域。较少的