Patent ID: 6399485
Filing Date: 2002-06-04
Classification: H01L

Abstract:
A method of selectively forming a silicide layer in a semiconductor device having a first impurity concentration; at least a second diffusion layer having a first impurity concentration which is lower than said first impurity concentration, and said first and second diffusion layers being of the same conductivity type, said comprising the steps of:forming a mask layer at least over said second diffusion layer; carrying out a first ion-implantation of an impurity of the same conductivity type as said first and second diffusion layers by use of said mask layer as a mask so as to ion-implant said impurity into an upper region of said first diffusion layer, whereby an amorphous silicon layer is formed over said first diffusion layer whilst no amorphous silicon layer is formed over said second diffusion layer; forming a metal layer on said amorphous silicon layer over said first diffusion layer and also on said mask layer; and carrying out a heat treatment to cause a silicidation reaction of metal in said metal layers with silicon in said amorphous silicon layer whereby a metal silicide layer is selectively formed over said first diffusion layer whilst no silicide layer is formed over said second diffusion layer.