US Patent 10256161 Dual work function CMOS devices

A method for forming a semiconductor device includes forming a first channel region and a second channel region on a substrate, depositing a dielectric material layer on the first channel region and the second channel region, and depositing a barrier layer on the dielectric material layer on the first channel region and the second channel region. A metal layer is deposited on the barrier layer on the first channel region and the second channel region. A portion of the metal layer and the barrier layer on the first channel region and a portion of the metal layer on the second channel region are removed to expose the barrier layer on the second channel region. A layer of workfunction material is deposited on an exposed portion of the dielectric material layer on the first channel region and over the barrier layer on the second channel region.