Patent ID: 6300217
Filing Date: 2001-10-09
Classification: H01L,Y10S

Abstract:
A method for fabricating a semiconductor device comprising the steps of:(a) setting the temperature of a substrate held in a vapor deposition apparatus of a system to a first temperature;(b) depositing an amorphous silicon layer on a surface of said substrate by introducing a source gas containing silicon into said vapor deposition apparatus such that said source gas is decomposed in the vicinity of the surface of said substrate;after said depositing step,(c) elevating the temperature of said substrate from said first temperature to a second, higher temperature capable of pyrolytically decomposing an oxidation gas, but not capable of crystallizing the amorphous silicon,(d) introducing an oxidation gas into said vapor deposition apparatus which gas pyrolytically decomposes at the second temperature to form a thin oxide film less than 5 nanometers on the surface of said amorphous silicon layer; and(e) increasing the temperature to a third higher temperature capable of crystallizing the amorphous silicon;(f) crystallizing said amorphous silicon layer by holding the temperature of said substrate at said third temperature to convert said amorphous silicon layer to a polysilicon layer;wherein said thin oxide film suppresses diffusion of silicon atoms along a surface of said amorphous silicon layer during the crystallizing step, and thereby prevents the development of a rough surface on the polysilicon layer produced by the crystallizing step; and(g) reducing the temperature and applying an SiO.sub.2 layer on the oxide layer.