An analytical model of hole confinement gate voltage range for SiGe-channel p-MOSFETs

This paper describes an analytical model of hole confinement gate voltage range (V/sub hc/) for SiGe-channel p-MOSFETs. The model shows that V/sub hc/ depends on threshold voltage, gate oxide to Si cap thickness ratio, Ge mole fraction at the top of SiGe channel, work function of gate material, and substrate doping. With device scaling and power supply reduction, the Si cap should be thinned by the same magnitude as the gate oxide to realize full bias range SiGe-channel operation. Various bulk and SOI SiGe p-MOSFETs are clarified to have the same hole confinement capability with threshold voltage adjusted to the value required by circuit application.