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Epitaxial Growth of High Quality SiC by Sublimation Close Space Technique with High Growtn Rate

高生长率升华近距离技术外延生长高质量SiC

基本信息

批准号：
09450011
负责人：
NISHINO Shigehiro
金额：
$ 8.83万
依托单位：
Kyoto Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450011/
关键词：
silicon carbide epitaxial growth sublimation method 6H-SiC epitaxial layer closed space technique sublimation epitaxy SiC device SiC think film SiC 昇華エピアキシャル成長

项目摘要

In CST method, growth is promoted by sublimation and diffusion transfer in a narrow space which is constructed by source, substrate and graphite spacer. This method is basically same as conventional sublimation method for SiC-bulk. One big difference of configuration is the distance between source and substrate. We used 3C-SiC polycrystalline plate with high purity as source and High growth was achieved at a temperature range of 2200-2400ﾟC, and it was around 40-200 mu m/h. Activation energy obtained by temperature dependence of the growth rate was l47kcal/mol. By introducing off-angle to the substrate, a mirror-like morphology was obtained in the wide temperature range. Step bunching was also observed and trace width of the step was about 5 mu m. A defect having line shaped shadow was observed along <1120> direction, and it indicates that crystal growth followed step-flow mechanism. Surface morphology is often affected by many parameters such as spacer height. When the spacer height decreased, wavy pattern appeared. When the height increased, rather smooth surface appeared. Ta-sheet was also used to avoid unwanted carbon species from the wall of crucible. Appropriate condition, very smooth surface was obtained, however, carbonization of Ta seems a key parameter to get high quality SiC epilayer. Epilayer made in Ta pasted crucible, step-bunching free surface was obtained. Donor-acceptor pair emission was greatly suppressed in the photoluminescense measurement In this photoluminescence, RO and So lines, which is related excitons bound to neutral N donors, were observed. It means epitaxial layers are of high quality. These lines were especially observed epitaxial layers with high growth rate such as more than 100 mu m/h. It indicates that increasing growth rate may be useful to decrease impurity density doped into epitaxial layers. We made Schottky diodes showed breakdown voltage of 40V without edge termination.

在CST方法中，通过在由源、衬底和石墨间隔物构成的狭窄空间内的升华和扩散转移来促进生长。该方法与传统的块状碳化硅升华方法基本相同。配置的一大差异是源和基板之间的距离。我们采用高纯度的3C-SiC多晶板作为原料，在2200-2400℃的温度范围内实现了高生长，生长速度约为40-200μm/h。由生长速率的温度依赖性获得的活化能为l47kcal/mol。通过向基底引入斜角，在较宽的温度范围内获得了镜面形貌。还观察到台阶聚束并且台阶的迹线宽度约为5μm。沿<1120>方向观察到具有线状阴影的缺陷，表明晶体生长遵循阶梯流机制。表面形态通常受到许多参数的影响，例如垫片高度。当垫片高度降低时，出现波浪图案。当高度增加时，出现相当光滑的表面。 Ta-sheet 还用于避免坩埚壁上出现不需要的碳物质。在适当的条件下，可以获得非常光滑的表面，然而，Ta的碳化似乎是获得高质量SiC外延层的关键参数。在Ta糊坩埚中制作外延层，得到阶梯聚束自由表面。在光致发光测量中，供体-受体对发射被大大抑制。在该光致发光中，观察到RO和So线，其是与中性N供体结合的相关激子。这意味着外延层的质量很高。这些线是特别观察到的具有高生长速率(例如超过100μm/h)的外延层。这表明增加生长速率可能有助于降低掺杂到外延层中的杂质密度。我们制造的肖特基二极管的击穿电压为 40V，无边缘终止。