Tunnel FET with non-uniform gate capacitance for improved device and circuit level performance

We report the significant improvement obtained by a non-uniform gate capacitance made by appropriate combination of high-k and low-k regions over the tunneling and the channel regions of a heterostucture TFET (called HKLKFFET). In addition to significantly enhanced ION and subthreshold swing, we find that this structure offers great improvements for the dynamic switching energy (66% saving) and propagation delay (similar to 3 x fast operation) compared to a heterostructure TFET (HeTFET) due to the reduction of the Miller effect. We compare and benchmark the proposed device against a 65 nm low stand-by power (LSTP) CMOS technology, and we show that at a supply voltage of V-DD = 0.4 V, TFETs can have smaller propagation delays compared to CMOS operating in the subthreshold region. Higher cut-off frequency (similar to 3x) and bandwidth for analog applications is observed in circuit-level simulations. (C) 2013 Elsevier Ltd. All rights reserved.