Steep switching less than 15 mV dec−1 in silicon-on-insulator tunnel FETs by a trimmed-gate structure

We study a novel trimmed-gate (TG) structure, which substantially decreases the subthreshold swing (SS) of a tunnel field-effect transistor (TFET). Our technology computer-aided simulations demonstrate that the TG structure strongly suppresses the off leak component of the band-to-band tunneling current. As a result, an extremely steep SS of less than 15 mV dec−1 can be realized in a silicon-on-insulator (SOI) TFET. We also demonstrate that the improvement of SS is enhanced by a high source doping thanks to the TG structure. The mechanism of the steep switching by the TG structure does not depend on any specific material or process technology. Therefore, the SS improvement as a result of the TG structure is applicable to various types of TFETs as well as the SOI TFET.