High performance CMOS transistors using PMD liner stress

摘要

A silicon nitrate layer (110) is formed over a transistor gate (40) and source and drain regions (70). The as-formed silicon nitride layer (110) comprises a first tensile stress and a high hydrogen concentration. The as-formed silicon nitride layer (110) is thermally annealed converting the first tensile stress into a second tensile stress that is larger than the first tensile stress. Following the thermal anneal, the hydrogen concentration in the silicon nitride layer (110) is greater than 12 atomic percent.

主权项

1. A method of forming an integrated circuit, comprising:
providing a semiconductor substrate; forming a gate dielectric layer on a surface of said semiconductor substrate; forming a first gate electrode over said gate dielectric layer for a PMOS device; forming a second gate electrode over said gate dielectric layer for an NMOS device; forming sidewall structures adjacent said first gate electrode and said second gate electrode; forming source and drain regions in said semiconductor substrate adjacent said sidewall structures; forming a high stress liner layer over the first gate electrode, the second gate electrode and the source and drain regions by:
forming a silicon nitride layer with a hydrogen concentration greater than 20 atomic percent and a first tensile stress over said first gate electrode, said second gate electrode, and said source and drain regions; andthermally annealing said silicon nitride layer before forming any additional layers on the silicon nitride layer, resulting in a second tensile stress greater than 800 mPa and a second hydrogen concentration greater than 12 atomic % in said silicon nitride layer for the PMOS device and the NMOS device thereby exerting a tensile stress in a channel region of the NMOS device, enhancing channel mobility for the NMOS device without substantially affecting channel mobility of the PMOS device; and forming a pre-metal dielectric (PMD) layer on the high stress liner layer after thermal annealing.