Channel-stress study on gate-size effects for damascene-Gate pMOSFETs with top-cut compressive stress liner and eSiGe

Damascene gate process enhances the drivability in shorter gate length region, as compared to conventional gate 1st process for pFETs with compressive stress SiN liner and embedded SiGe. The origin of the gate length effect is investigated for the first time by using the UV-Raman spectroscopy. Moreover, the relationship between channel strain and gate width for damascene gate pFETs is analyzed and the effect is also demonstrated. It is found that channel strain is considerably enhanced in shorter gate length and narrower gate width by the combination of damascene gate process and stress enhancement techniques.