Abstract: A first option is a method of forming an ultra thin buffer oxide layer comprises the following steps. A silicon substrate having STI regions formed therein separating at least one active area is provided. The silicon substrate has an upper surface. A sacrificial oxide layer is formed over the silicon substrate and the STI regions. Oxygen is implanted within the silicon substrate. The oxygen implant having a peak concentration proximate the upper surface of the silicon substrate. The sacrificial oxide layer is stripped and removed. A gate dielectric layer is formed over the silicon substrate. A conductor layer is deposited over the gate dielectric layer. The structure is annealed to form ultra-thin buffer oxide layer between the silicon substrate and the gate dielectric layer. A second option is a method of forming an ultra-thin buffer oxide layer, comprises the following steps. A silicon substrate having STI regions formed therein separating at least one active area is provided.

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 H2-rich PECVD silicon nitride layer is deposited over the undoped silicate glass layer and over the PMOS and NMOS transistors. The H2-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 H2-rich PECVD silicon nitride layer overlying the NMOS transistor into the source/drain of the NMOS transistor.