1989 Fiscal Year Final Research Report Summary
New Technique to Grow High Quality SOI layer
| Project/Area Number |
62850052
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 | The University of Tokyo |
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Principal Investigator |
NISHINAGA Tatau Univ. Tokyo, Fac. of Engineering, Professor, 工学部, 教授 (10023128)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Takao Shin-Etsu Handotai Co., Ltd., Semicond. R&D Cent., Head, 半導体研究所, 研究部長
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| Project Period (FY) |
1987 – 1989
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| Keywords | Si / GaAs / LPE / Epitaxial Lateral Overgrowth / SOI |
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| Research Abstract |
High quality SOI film was obtained by epitaxial lateral overgrowth (ELO) with LPE. Since LPE is carried out with almost thermally equilibrium process, it has three advantages as follows: (1) Good crystal quality (2) Large ratio of lateral width to vertical thickness (ELO ratio) (3) High flatness because the grown surface is covered with a facet. For ELO, the substrate is limited to the (111) surface. Sn was used as a solvent.
First, the growth mechanism of the ELO was studied. It was found that in the circular seeds the growth occurred at steps which were supplied not only by screw dislocations and the misoriented substrate but also by 2D nucleation. Growth from the line seeds was found to occur almost at steps supplied by the misoriented substrate, while sometimes the screw dislocation was introduced at the periphery of the ELO where 2D cellular structure was formed because of the morphological instability. It was found that it is important to keep the supersaturation as low as possible to prevent morphological instability. ELO ratio was improved to 75 and the step free facet was obtained at the optimum condition.
Second, the technique to control ELO thickness was developed. ELO layer was grown from a ridge seed. Its thickness was same as the height of the ridge. Therefore, ELO thickness can be controllable by adjusting the height of the ridge. 0.23 um thick layer was grown and ELO thickness was shown to be controllable to the order of 100 nm. With this technique the ELO ratio was improved to 163.
Finally, crystal quality of ELO layer was evaluated by Sirtl etching. Dislocations were completely eliminated by the growth at the low supersaturation. This result indicates that the ELO layer has a good crystal quality.
In summary, new technique has been developed for obtaining high quality SOI layer by using LPE lateral overgrowth.
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Research Products
(20 results)
