多晶硅CWAr^+激光再结晶功率窗的探讨

PROBE INTO POWER WINDOW OF CWAr^+ LASER RECRYSTALLIZATION OF POLYSILICON

近年来在绝缘衬底上激光再结晶的多晶硅膜内制作SOI器件受到广泛重视.人们对SOI结构的制备及性质,尤其是对多晶硅层和绝缘衬底间的界面面性质进行了广泛的研究.作者曾提出激光功率窗口的概念,激光功率在这个窗口内,才能制出性能良好的SOI再结晶材料.降低窗口对应的功率,拓宽功率窗口是SOI材料和器件制备中的重要问题.

The poly-orystalline silicon films deposited on an insulating substrate by LPCVD are recrystallized by CWAr+ laser irradiation. According to the relations between the average crystal-grain size and the laser power, we can divide the recrystallizing process into three stages, called solid phase crystallization, liquid phase crystallization and saturated crystallization. There exists a power window restricted by the recrystallized grain size, the properties of the interface between the polysilicon and SiO2 layer as well as the irradiation damages. In this paper we analyse the mechanism of the formation of the irradiation damage and propose to diverge the laser beam and increase the thickness of SiO2 in order to widen the power window.