Performance improvement in novel germanium-tin/germanium heterojunction-enhanced p-channel tunneling field-effect transistor

摘要

We design a novel GeSn-based heterojunction-enhanced p-channel tunneling field-effect transistor (HE-PTFET) with a Ge_(0.92)Sn_(0.08)/Ge heterojunction located in channel region, at a distance of L_(T-H) from the Ge_(0.92)Sn_(0.08) source-channel tunneling junction (TJ). HE-PTFETs demonstrate the negative shift of onset voltage V_(onset). the steeper subthreshold swing S, and the improved on-state current I_(On) compared to Ge_(0.92)Sn_(0.08) homo-PTFET. At low V_(Gs). the suppression of BTBT due to the widening of the tunneling barrier caused by the heterojunction leads to a negative shift of V_(onset) in HE-PTFETs. At high V_(Gs), I_(on) enhancement in HE-PTFETs is achieved over the homo device, which is attributed to the confinement of BTBT in Ge_(0.92)Sn_(0.08) source-channel TJ region by the heterojunction, where the short tunneling paths lead to a high tunneling probability. Due to the steeper average S, HE-PTFET with a 6 nm L_(T-H) achieves a 4 times higher I_(On) compared to homo device at a V_(DD) of -0.3 V.