Patent ID: 8884374

Claim:
A method of forming a complementary metal-oxide-semiconductor (CMOS) device comprising: providing a semiconductor substrate including a first region to form a PMOS transistor and a second region to form an NMOS transistor, the first region including a metal gate structure including a metal top layer of a metal gate, the second region including an interfacial oxide layer formed on a high-k dielectric layer; oxidizing a surface of the metal top layer in the first region to form a metal oxide top layer covering a remaining metal top layer; wet etching in a same step to simultaneously remove the metal oxide top layer in the first region and the interfacial oxide layer in the second region, to expose the remaining metal top layer as the metal gate in the first region and to expose the high-k dielectric layer in the second region; and forming a metal gate on the high-k dielectric layer that has been exposed in the second region.