Method to selectively strain nmos devices using a cap poly layer

Abstract

The present invention facilitates semiconductor fabrication by providing methods of fabrication that selectively apply tensile strain to channel regions of devices while mitigating masking operations employed. A cap poly layer is formed over NMOS and PMOS regions of a semiconductor device. Then, a resist mask is employed to remove a portion of the cap poly layer from the PMOS region. Subsequently, the same resist mask and/or remaining portion of the cap poly layer is employed to form source/drain regions within the PMOS region by implanting a p-type dopant. Afterward, a cap poly thermal process is performed that causes tensile strain to be induced only in channel regions of devices located within the NMOS region. As a result, channel mobility and/or performance of devices located in the PMOS region is not substantially degraded.