Method of fabricating semiconductor device having sidewall spacers and

Abstract

First, a low-concentration impurity layer is formed by obliquely implanting an n-type impurity at a prescribed angle with respect to the surface of a p-type semiconductor substrate, using a gate electrode formed on the semiconductor substrate as a mask. Thereafter a sidewall spacer is formed on the sidewall of the gate electrode, and then a medium-concentration impurity layer is formed by obliquely implanting an n-type impurity to the surface of the semiconductor substrate. Thereafter a high-concentration impurity layer is formed by substantially perpendicularly implanting an n-type impurity with respect to the surface of the semiconductor substrate. According to this method, the low-concentration impurity layer in source and drain regions having triple diffusion structures can be accurately overlapped with the gate electrode, with no requirement for heat treatment for thermal diffusion.