1999 Fiscal Year Final Research Report Summary
Structure control of semiconductor hetero-ineterfaces utilizing 'hydrogen atom' as mediators
| Project/Area Number |
09305002
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | Tokyo Institute of Technology |
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Principal Investigator |
SHIMIZU Isamu Interdisciplinary Graduate School of Science and Engineering, Professor, 大学院・総合理工学研究科, 教授 (40016522)
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| Co-Investigator(Kenkyū-buntansha) |
KAMIYA Toshio Material Structures Laboratory, Research associate, 応用セラミックス研究所, 助手 (80233956)
FORTMANN C.M. Interdisciplinary Graduate School of Science and Engineering, Professor, 大学院・総合理工学研究科, 教授 (70293066)
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| Project Period (FY) |
1997 – 1999
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| Keywords | atomic hydrogen / structure control / high mobility / VHF plasma / SiFィイD24ィエD2 / solar cell |
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| Research Abstract |
This work focused on the development of new technique to prepare high quality semiconductor materials with the assistance of hydrogen atoms. In our previous studies, it was confirmed that high flux hydrogen atoms generated by plasma affected on structure and property of semiconductors such as II-VI compound Zn(S,Se) and polycrystalline silicon.
We made a VHF plasma CVD apparatus which had two deposition chambers connected with a gate-valve by way of an experiment to investigate the way to prepare high quality semiconductors and their hetero-interfaces. We confirmed that high quality, high crystallinity polycrystalline silicon (poly-Si) could be prepared on glass at temperatures lower than 400℃ by using SiFィイD24ィエD2 and HィイD22ィエD2 mixing gas. It should be noted that an interesting result was obtained : i.e., orientation structure of poly-Si were controlled by selecting appropriate SiFィイD24ィエD2/HィイD22ィエD2 gas ratio : i.e., (220) orietated poly-Si were grown at small SiFィイD24ィエD2/HィイD22ィエD
… More
2 ratio conditions while (400) oriented poly-Si were grown at larger SiFィイD24ィエD2/HィイD22ィエD2 ratios. Especially, the preparation of (400) oriented poly-Si on glass at low temperatures < 400℃ has been very difficult subject until this study and they showed very excellent structural and transport properties. These features let us expect that the (400) oriented poly-Si are promising materials for high operation speed TFTs. Also it was confirmed that rather high crystal fraction (83%) poly-Si were prepared at rather low temperatures of >150℃ and very small addition of SiHィイD24ィエD2 to source gas effectively increased growth rate by promoting gaseous reaction in plasma.
From the investigation for growth mechanism of these preferentially oriented poly-Si, we obtained detailed relationship between growth rate, film structure, SiFィイD24ィエD2/HィイD22ィエD2 ratio and growth temperature. It was found that very surface sensitive growth is occurred under the deposition condition Where (400) oriented poly-Si are grown : especially, deposition precursors have very strong selectivity for sticking to Si 100 surface. Also selective etching of specific crystallographic plane was observed at near this condition. These results indicate that (400) preferential growth is determined by the balance between selective sticking of precursors and selective etching of specific planes. Less
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