Semiconductor devices having metal containing n-type and p-type gate electrodes and methods of forming the same

Abstract

A semiconductor device has at least two different gate electrodes. The two different gate electrodes include a first gate electrode on a first gate insulation layer. The first gate electrode includes a first metal-containing conductive pattern on the first gate insulation layer and a second metal-containing conductive pattern. A second gate electrode is provided on a second gate insulation layer and includes a third metal-containing conductive material on the second gate insulation layer. The first metal-containing conductive pattern and the third metal-containing conductive pattern have different work functions from each other. A surface of the second metal-containing conductive pattern and a surface of the third metal-containing conductive pattern are substantially planar. Methods of fabrication such semiconductor devices are also provided.