1991 Fiscal Year Final Research Report Summary
Graphoepitaxial Growth of Semiconductor Thin Film on the Textured Natural Crystalline Surface Relief Duplicated on a Foreign Substrate
| Project/Area Number |
02650224
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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 | Toyama Prefectural University |
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Principal Investigator |
TAKAKURA Hideyuki Toyama Prefectural University, Associate Professor, 工学部, 助教授 (30112022)
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| Co-Investigator(Kenkyū-buntansha) |
HAMAKAWA Yoshihiro Osaka University, Professor, 基礎工学部, 教授 (10029407)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Graphoepitaxy / Germanium / Thin Film / Euectic Alloy / Solar Cell |
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| Research Abstract |
According to the epitaxial growth mechanism, it can be expected that single crystalline thin film could be grown on any substrates of quite different crystalline structure if certain perturbation with some crystallographic period and symmetry were written on the amorphous substrate surface and the crystal growth were affected by the periodic pattern. This technology is generally called "Graphoepitaxy". The purpose of this work is the establishment of a technology to produce a large area single crystalline semiconductor thin film utilizing this graphoepitaxial growth phenomenon and assessment of the probability of the application to a semiconductor devices which requires a very large area such as solar cells and display devices.
In 1990, an infrared light annealing apparatus was newly introduced and got basic technical data on the recrystallization of Ge film. It is also pursued that the same kind of graphoepitaxial growth from eutectic alloy would be occurred as was seen in Ge graphoepi
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taxy in our previous work. However, Si reacts with alloy metal aswell as the substrate and it is very difficult to obtain large single crystalline Si thin film. It was decided from this results, to revise, the main purpose to establish a technique to produce large area growth of Ge from Si graphoepitaxy. In 1991, a new structure of the graphoepitaxial growth substrate was proposed and the fabrication technique was established. The substrate relief in this work has the shape of pyramid fabricated by a selective etching of Si(100)wafer. Our previous substrate had this pyramidal relief on whole area of substrate. Crystallographic orientation of grown crystallite was controlled by the surface relief of each growing sites. However, very small orientation mismatch create many grain boundaries and obtained grain size is around 0.01mm at most. New structure is partially textured one. The size of the textured part is determined to be the same order of the grain size in our previous work on which we can made single grain crystal. On the remained area, semiconductor film could be grown laterally utilizing the graphoepitaxially grown single grain on the textured part as a seed. Systematic technical data on the substrate fabrication were collected using Si(100)wafers. The partially textured Si wafer was oxided to prevent epitaxial growth, and W, Al and Ge were deposited successively. After that, Ge film was recrystallized by infrared light annealing apparatus. Annealed Ge film on the flat substrate had(111)texture which is essentially required condition in graphoepitaxy. However we cannot see graphoepitaxy phenomenon on the pyramidal relief part. Careful characterization of grown Ge film implied that annealing temperature is not sufficient as compared with the annealing by Ar laser. More rapid and higher temperature annealing of more than 600ﾟC is found to be necessary. Less
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