Stacked Gate-All-Around Nanosheet pFET with Highly Compressive Strained Si1-xGex Channel

Stacked Gate-All-Around (GAA) nanosheet pFETs with compressively strained Si
_1-x
Ge
_x
channel have been fabricated to explore their electrical benefits. The Si
_1-x
Ge
_x
NS channel structure with high crystalline quality and 1GPa compressive stress has been realized for the first time. Systematic study has been performed to understand the effect of epitaxial Si
_1-x
Ge
_x
thickness, Ge fraction, and Si cap thickness on the Si
_1-x
Ge
_x
NS channel device characteristics. It is found that the compressively strained Si
_1-x
Ge
_x
NS channel provides a 100% uplift in peak hole mobility with a corresponding channel resistance reduction of 40% while maintaining an excellent subthreshold slope of below 70 mV/dec.