Selective formation of hydrogen rich pecvd silicon nitride for improved nmos transistor performance

Abstract

A method of selective formation of SiN layer in a semiconductor device comprising the following steps. A semiconductor structure having at least one PMOS transistor and one NMOS transistor formed therein is provided. The PMOS and NMOS transistors each have source/drain regions, a gate, and salicide contact regions. An undoped silicate glass (USG) layer is deposited over the semiconductor structure and the PMOS and NMOS transistors. An H -rich PECVD silicon nitride layer is deposited over the undoped silicate glass layer and over the PMOS and NMOS transistors. The H -rich PECVD silicon nitride layer is patterned, etched, and removed from over the PMOS transistor. An inter-level dielectric (ILD) layer is formed over the structure. The ILD layer is densified whereby hydrogen diffuses from the H -rich PECVD silicon nitride layer overlying the NMOS transistor into the source/drain of the NMOS transistor.