Process for forming mos device in integrated circuit structure using

Abstract

A process which is capable of forming shallow source/drain regions in a silicon substrate and a doped gate electrode by implantation of cobalt silicide contacts of uniform thickness previously formed on the substrate followed by diffusion of the dopant into the substrate to form the desired source/drain regions, and into the polysilicon gate electrode to provide the desired conductivity is described. The process comprises: first depositing a layer of cobalt over a polysilicon gate electrode and areas of a silicon substrate where source/drain regions will be formed; then forming at least one capping layer over the cobalt layer; then annealing the structure at a first temperature to form cobalt silicide; then removing the capping layer, as well as the unreacted cobalt and any cobalt reaction products other than cobalt silicide; then annealing the structure again at a higher temperature than the first anneal to form high temperature cobalt silicide; then implanting the cobalt silicide with one or more dopants suitable for forming source/drain regions in the silicon substrate and for increasing the conductivity of the polysilicon gate electrode; and then heating the structure sufficiently to cause the implanted dopant or dopants in the cobalt silicide to diffuse into the substrate to form the desired source/drain regions and into the polysilicon gate electrode to increase the conductivity thereof.