Growth of Dislocation-Free Single Crystal Silicon Sheet

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 08455076
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 機械工作・生産工学
• Research Institution: Osaka University
• Principal Investigator: YASUTAKE Kiyoshi Precision Science and Technology, Associate Professor, 大学院・工学研究科, 助教授 (80166503)
• Co-Investigator(Kenkyū-buntansha): KAKIUCHI Hiroaki Precision Science and Technology, Research Associate, 大学院・工学研究科, 助手 (10233660) ; YOSHII Kumayasu Precision Science and Technology, Professor, 大学院・工学研究科, 教授 (30029152)
• Project Period (FY): 1996 – 1998
• Keywords: dislocation-free single crystal Si / Si sheet / liquid phase crystal growth

Research Abstract

The aim of this study is to develop a growth method of dislocation-free single crystal Si sheet. Basically, a method of liquid phase crystal growth (LPCG) from Si-containing solvent has been used. To obtain sheet-shaped crystal, we studied longitudinal growth in shaping slits and graphoepitaxy on grooved glass substrates.
(1) A dislocation-free single crystal Si of 12 x 5 x 3 mn^3 has been grown by the LPCG method. The surface orientation of the crystal was (111) and the resistivity was 10 - 20 OMEGAcm. By this result, we could show the possibility of the LPCG method to achieve continuous growth of dislocation-free single crystal Si sheet.
(2) Th principle, it is possible to grow dislocation-free single crystal Si sheet that floats on the Sn solvent during the process (floating method). To grow Si sheets by the floating method, detailed simulation study is necessary on the Si supersaturation due to the temperature distribution taking the buoyancy effects into account.
(3) The longitudinal LPCG method with shaping slits is the most promising method for practical production line. In this method, the solution should be introduced into the shaping slits with the assistance of the applied pressure. The temperature gradient along the shaping slits should be rigorously controlled. At the first stage, this method is applicable for solar cells. On the application for the LSI devices, more detailed electrical characterization is necessary.
(4) The graphoepitaxy on grooved glass substrates may be effective for LSI application, because the thinner Si layer than 0.1 mum is easily grown by the LPCG method . However, the grooving technique to obtain periodical pattern with atomic order is necessary to be developed, which can not be achieved by the present X-ray lithography technique.
(5) In order to grow large area Si sheet, it is necessary to develop a large-scale equipment, which makes it possible to feed Si material continuously, to maintain the constant solvent temperature, and to precisely control the temperature around the crystal growth region.