High Ion/Ioff Ge-source ultrathin body strained-SOI tunnel FETs

High performance operation of Ge-source/strained-Si-channel hetero-junction tunnel FETs is demonstrated. It is found that tensile strain in Si-channels can enhance the tunneling current because of the reduced effective energy bandgap, E
_g.eff
. Nitrogen heat-treatment can improve the gate-to-channel MIS interface which causes SS improvement. The fabricated Ge/sSOI(1.1 %) tunnel FETs show high I
_on
/I
_off
ratio over 10
⁷
and steep minimum SS of 28 mV/dec. Back biasing effects are also investigated and the I
_on
and average SS are improved by positive back biasing.