Device Physics and Design of a L-Shaped Germanium Source Tunneling Transistor

Abstract

A novel tunneling field-effect transistor (TFET) with an L-shaped Ge source is investigated. The device comprises a Ge source that extends underneath a Si-channel region and separated from the drain by an insulator (SiO₂). By optimizing the overlap length of the extended source L _OV and the Si body thickness T _Si, the current due to vertical band-to-band tunneling (BTBT) of the Ge–Si hetero-junction could be increased significantly and is scalable with L _OV. This leads to higher I _ON and improved S. The SiO₂ also reduces OFF-state current I _OFF by blocking leakage paths. With extensive simulation, the device physics and design guidelines of this novel structure are outlined.