The optimizations to metal gate structure and film process were extensively investigated for great metalgate stress(MGS) in 20 nm high-k/metal-gate-last(HKVMG-last) nMOS devices.The characteristics of advanced MGS technologies on device performances were studied through a process and device simulation by TCAD tools. The metal gate electrode with different stress values(0 to—6 GPa) was implemented in the device simulation along with other traditional process-induced-strain(PIS) technologies like e-SiC and nitride capping layer.The MGS demonstrated a great enhancing effect on channel carriers transporting in the device as device pitch scaling down.In addition,the novel structure for a tilted gate electrode was proposed and relationships between the tilt angle and channel stress were investigated.Also with a new method of fully stressed replacement metal gate(FSRMG) and using plane-shape-HfO to substitute U-shape-HfO,the effect of MGS was improved.For greater film stress in the metal gate,the process conditions for physical vapor deposition(PVD) TiN-x- were optimized.The maximum compressive stress of—6.5 GPa TiN_x was achieved with thinner film and greater RF power as well as about 6 sccm N ratio. The optimizations to metal gate structure and film process were extensively investigated for great metalgate stress (MGS) in 20 nm high-k / metal-gate-last (HKVMG-last) nMOS devices. Characteristics of advanced MGS technologies on device were were studied through a process and device simulation by TCAD tools. The metal gate electrode with different stress values ​​(0 to-6 GPa) was implemented in the device simulation along with the other traditional process-induced-strain (PIS) technologies like e-SiC and nitride Capping layer. MGW demonstrated a great enhancing effect on channel carriers transporting in the device as device pitch scaling down. In addition, the novel structure for a tilted gate electrode was proposed and relationships between the tilt angle and channel stress were investigated. Also with a new method of fully stressed replacement metal gate (FSRMG) and using plane-shape-HfO to substitute U-shape-HfO, the effect of MGS was improved. For greater film stress in the metal ga te, the process conditions for physical vapor deposition (PVD) TiN-x-were optimized.The maximum compressive stress of-6.5 GPa TiN_x was achieved with thinner film and greater RF power as well as about 6 sccm N ratio.