Hump Effects of Germanium/Silicon Heterojunction Tunnel Field-Effect Transistors

Abstract

The hump effects of germanium/silicon heterojunction tunnel field-effect transistors are discussed. Simulation results show that they are originated when indirect band-to-band tunneling is converted into direct one as gate voltage ( $V_{g}$ ) increases. In order to suppress the hump effects, two ideas are proposed. First, the length of intrinsic-germanium channel ( $L_{\mathrm{ Ge}}$ ) is optimized using a novel process flow. Second, gate-to-channel coupling is improved by increasing source doping concentration ( $N_{S}$ ).