Effect of SiO2 Capping Layer on a Laser Crystallization of a-Si Thin Film

Abstract

AbstractEffect of SiO2 capping layer(C/L) on recrystallization of amorphous Si (a-Si) film was investigated. When a thick C/L over 500 Å was deposited on an a-Si film before crystallization, fine p-Si grains less than 100nm were obtained at full range of energy density window. However, when a thin C/L below 200 Å was used, Si-melt spouted out through C/L at over critical energy density. When Si-melt started spouting, abrupt change of grain size also occurred. These large grains could be explained by a non-uniformity of heat flow caused by Si-melt spouting. With this polycrystalline Si (p-Si) material having appreciable grain size protected by C/L, fabrication of low-cost Low Temperature Poly Si (LTPS) without additional cleaning of p-Si surface could be successfully developed.