1994 Fiscal Year Final Research Report Summary
Large area annealing of semiconductor thin films by high power excimer lasers excited by elecron beam
| Project/Area Number |
04650263
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子材料工学
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| Research Institution | University of Electro-Communications |
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Principal Investigator |
OKAMOTO Kotaro University of Electro-Communications, Department of Electronic Engineering, Professor, 電気通信学部, 教授 (80017350)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Koichi University of Electro-Communications, Department of Electronic Engineering, Rese, 電気通信学部, 助手 (40191225)
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| Project Period (FY) |
1992 – 1994
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| Keywords | excimer laser anneal / polycrystal Si thin film |
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| Research Abstract |
The results obtained in this resarch were summarized as follows.
1.alpha-Si thin films were deposited by electron-beam evaporation under a high vacuum condition. From the SIMS measurments, it was found that the amount of hydrogen atoms incorporated into our alpha-Si films was less than that into the films deposited by a conventional low-pressure chemival vapor deposition. As a result, when our films were annealed by a laser irradiation, a hydrogen evaporation from the Si surfaces was suppressed, so that, the excellent thin films could be obtained without the damages.
2.In order to homogenize the light energy, the light reflector was constructed by multi-mirrors. By using this homogenizer, the alpha-Si films were crystallized uniformly.
3.The grain size of the Si polycrystals depended upon the film thickness. When the thickness was less than the melting depth, the crystallization rate became lower. This result indicated that a store of energy in the thinner films increased. that is, it was considered that the thinner films were easy to be kept under a thermal equilibrium condition. The above effect was important to increase the grain size.
4.The Si thin films were heated during the laser annealing because of the continuance of thermal equilibrium. Therefore, the grain size of Si polycrystals increased, and, the crystallization uniformity was enhanced.
5.The quality of Si polycrystals depended on the laser power, hence, it was necessary to select an optimum power. In particular, many hillocks were observed on the Si surfaces irradiated at a higher power.
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