Selective growth of a work-function metal in a replacement metal gate of a semiconductor device

摘要

Approaches for forming a replacement metal gate (RMG) of a semiconductor device, are disclosed. Specifically provided is a p-channel field effect transistor (p-FET) and an n-channel field effect transistor (n-FET) formed over a substrate, the p-FET and the n-FET each having a recess formed therein, a high-k layer and a barrier layer formed within each recess, a work-function metal (WFM) selectively grown within the recess of the n-FET, wherein the high-k layer, barrier layer, and WFM are each recessed to a desired height within the recesses, and a metal material (e.g., Tungsten) formed within each recess. By providing a WFM chamfer earlier in the process, the risk of mask materials filling into each gate recess is reduced. Furthermore, the selective WFM growth improves fill-in of the metal material, which lowers gate resistance in the device.