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

We design a novel GeSn-based heterojunction-enhanced p-channel tunneling field-effect transistor (HE-PTFET) with a Ge0.92Sn0.08/Ge heterojunction located in channel region, at a distance of LT-H from the Ge0.92Sn0.08 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 Ge0.92Sn0.08 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-PTFTs is achieved over the homo device, which is attributed to the confinement of BTBT in Ge0.92Sn0.08 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 LT-H achieves a 4 times higher I-ON compared to homo device at a V-DD of -0.3 V. (C) 2015 Elsevier Ltd. All rights reserved.