Patent ID: 8003507

Claim:
A method of fabricating a semiconductor device comprising: providing a semiconductor substrate having a first region and a second region; forming a high-k dielectric layer over the semiconductor substrate; forming a first metal layer over the high-k dielectric layer, the first metal layer having a first work function; removing at least a portion of the first metal layer in the second region; thereafter, forming a semiconductor layer over the first metal layer in the first region and over the at least partially removed first metal layer in the second region; forming a first gate stack in the first region and a second gate stack in the second region; forming a dielectric over the semiconductor layer and semiconductor substrate, then removing a portion of the dielectric over the semiconductor layer; removing the semiconductor layer from the first gate stack thereby forming a first trench and from the second gate stack thereby forming a second trench; and forming a second metal layer on the first metal layer in the first trench and on the at least partially removed first metal layer in the second trench, the second metal layer having a second work function.