Stable and low resistance metal/barrier/silicon stack structure and related process for manufacturing

摘要

A metal-poly stack gate structure and associated method for forming a conductive barrier layer between W and poly in the metal-gate stack gate structure. The process includes the steps of depositing doped silicon on a substrate; forming nitride on the deposited silicon; depositing a metal on the nitride to form a metal/nitride/deposited silicon stack; and thermally treating the stack to transform the nitride into a conductive barrier layer between the metal and the deposited silicon. The thermal treatment transforms the nitride layer (SiNx or SiNxOy) into a conductive barrier (WSixNy or WSixNyOz) to form a W/barrier/poly stack gate structure. The barrier layer blocks reaction between W and Si, enhances sheet resistance, enhances adhesion between the W and the poly, and is stable at high temperatures.