Steep switching in trimmed-gate tunnel FET

We propose a tunnel field-effect transistor (TFET) having a trimmed gate (TG) structure, which considerably improves the subthreshold swing (SS). The TG structure truncates the needless long band-to-band tunneling (BTBT) paths to a “channel”, which normally appear in a conventional TFET, and realize a sudden switching to the on-state arising from a short BTBT path. Our simulations demonstrate that the TG-TFET can achieve an extremely steep SS, less than 10 mV/decade, in the double-gated Si-channel configuration. The TG structure also improves the ratio ION/IOFF to a value higher than that of ideal MOSFETs in the operation voltage range up to 0.35 V. The mechanism of steep switching is based on a simple modification of the gate electrostatic control; therefore, in addition to the demonstrated TFETs, the TG structure is universally applicable to many types of TFETs.