Design of complementary GAA-NW tunneling-FETs of axial Si-Ge heterostructure

With sub-16nm CMOS nodes looming, this work proposes a novel device structure for Gate-All-Around (GAA), Nanowire (NW) tunneling-FET (tFET), with axial heterojunction on the source-channel junction, gate-underlap on the drain end of the channel, and optimized doping levels of source and drain. This structure successfully suppresses the undesirable ambipolar transfer characteristics of conventional tFETs, while maintaining the advantage of small subthreshold swing of less than 60mV/dec. For the first time, an all-tFET inverter is demonstrated to exhibit excellent switching behaviors, out-performing both the homojunction Si NW-tFET and the conventional CMOS in inverters with the same gate length and supply voltage.