Process of making a polysilicon barrier layer in a self-aligned contact module

摘要

A method for forming a metal contact in a self aligned contact region over a impurity region in a substrate which comprises forming a doped polysilicon layer over the device surface except in a contact area. A thin polysilicon barrier layer and a metal layer, preferably tungsten, are then formed over the polysilicon layer and the contact area. The resulting metal contact has superior step coverage, lower resistivity, and maintains the shallow junction depth of buried impurity regions.