Method to eliminate polycide peeling

摘要

A method for forming MOSFET devices, with an improved polycide gate has been accomplished. The polycide structure, made with metal silicide on polysilicon has a reduced rate of adhesion loss or peeling of the metal silicide from the underlying polysilicon, due to the unique surface of the polysilicon. The desired surface of the polysilicon, that will reduce the peeling phenomena, is a wavy or undulated surface. This is accomplished by either depositing the polysilicon at conditions that result in a hemi-spherical grained surface, or obtaining a similar wavy or undulated surface by treating smooth polysilicon in either phosphoric acid or by anodization in hydrofluoric acid. The adhesion of the subsequent metal silicide to the wavy surface of the polysilicon is improved to a point where peeling of the metal silicide from the underlying polysilicon is eliminated.