US Patent 7943460 High-K metal gate CMOS

A method of forming a semiconductor device is provided that includes forming a Ge-containing layer atop a p-type device regions of the substrate. Thereafter, a first dielectric layer is formed in a second portion of a substrate, and a second dielectric layer is formed overlying the first dielectric layer in the second portion of the substrate and overlying a first portion of the substrate. Gate structures may then formed atop the p-type device regions and n-type device regions of the substrate, in which the gate structures to the n-type device regions include a rare earth metal.