Integration scheme method and structure for transistors using strained silicon

Abstract

A method for forming CMOS integrated circuits. The method forms a blanket layer of silicon dioxide overlying an entirety of the surface region of a first well region and a second well region provided on a semiconductor substrate. The blanket layer of silicon dioxide is overlying the hard mask on the first gate structure and the second gate structure. The blanket layer of silicon dioxide is also overlying a region to be protected. Depending upon the embodiment, the region can be a sidewall spacer structure and portion of an MOS device on a peripheral region of the substrate. Of course, there can be other variations, modifications, and alternatives. The method protects the region to be protected using a masking layer, while the surface region of the first well region and the second well region being exposed. The method selectively removes exposed portions of the blanket layer of silicon dioxide, including the hard mask on the first gate structure and the second gate structure, while exposing a first polysilicon material on the first gate structure and while exposing a second polysilicon material on the second gate structure. The method strips the masking layer. The method also includes forming a silicided layer overlying the first polysilicon material on the first gate structure and the second polysilicon material on the second gate structure, while the region to be protected remains free from the silicided layer.