Device physics and design of T-gate Schottky barrier tunnel FET with adaptive operation mechanism

Abstract

A T-shaped gate Schottky barrier tunnel FET (TSB-TFET) is discussed in detail and experimentally demonstrated with compatible bulk Si CMOS technology. The device can alleviate the major issues in traditional silicon TFET through adaptive operation mechanism, with higher ON-current from the dominant Schottky current, appreciably reduced off-leakage current from self-depletion effect, and steeper subthreshold slope (SS) from dominant band-to-band tunneling with enhanced source surface electric field through T-gate configuration. Without area penalty, the fabricated silicon-based device can achieve steeper SS over more than 4 decades of current and thus lower average SS, as well as higher ION/IOFF ratio of 106 compared with traditional TFET. The parameters for device design and analog circuit applications are studied as well. Simulation results show that TSB-TFET can achieve excellent on-off current trade-off by lowering the Schottky barrier height, and also demonstrate lower gate-to-drain capacitance and better analog parameters performance than traditional TFET.