1998 Fiscal Year Final Research Report Summary
Epitaxial Growth of High Quality SiC by Sublimation Close Space Technique with High Growtn Rate
| Project/Area Number |
09450011
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Kyoto Institute of Technology |
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Principal Investigator |
NISHINO Shigehiro Kyoto Institute of Technology, Faculty of Engineering and Design Professor, 工芸学部, 教授 (30089122)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAFUJI Tatsuru Kyoto Institute of Technology Faculty of Engineering and Design Research Associa, 工芸学部, 助手 (10235757)
HAYASHI Yasuaki Kyoto Institute of Technology Faculty of Engineering and Design Associate Profes, 工芸学部, 助教授 (30243116)
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| Project Period (FY) |
1997 – 1998
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| Keywords | silicon carbide / epitaxial growth / sublimation method / 6H-SiC epitaxial layer / closed space technique / sublimation epitaxy / SiC device / SiC think film |
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| Research Abstract |
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.
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