FORMING METHOD OF SOI SUBSTRATE AND PORMING METHOD OF SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a means for forming a very thin single crystalline semiconductor thin film. SOLUTION: A single crystalline silicon substrate 101 is anodized, and a porous silicon layer 102 is formed. After that, thermal treatment process at 900-1200 deg.C is performed in an reducing atmosphere. By this thermal treatment process, surface holes of the porous silicon layer 102 are covered, and a thin single crystalline silicon layer 103 is formed in the vicinity of the surface. The single crystalline silicon layer 103 is used as an active layer of an TFT(thin film transistor).