Patent ID: 8236686
Filing Date: 2012-08-07
Classification: H01L

Abstract:
1. A method of forming dual metal gates, the method comprising: forming a first metal layer directly over a gate dielectric layer and a second metal layer directly over the first metal layer, wherein the second metal layer substantially covers the first metal layer; removing a portion of the second metal layer to expose the first metal layer in a first region; forming one silicon layer directly over the exposed first metal layer in the first region and directly over the second metal layer in a second region; annealing the first metal layer and the second metal layer within the second region, such that elements of the second metal layer are mixed with the first metal layer and a first work function of the first metal layer within the second region is altered to a second work function, wherein the first work function is different from the second work function; and etching to form the dual metal gates in the first and second regions after the forming of the one silicon layer, wherein the first region includes: wherein the second region includes: