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

We propose and 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 HKLKTFET). In addition to significantly enhanced I_ON and subthreshold swing, we find that this structure offers great improvements for the dynamic switching energy (66% saving) and propagation delay (~3X 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 65nm low stand-by power (LSP) CMOS technology, and we show that at a supply voltage of V_DD = 0.4V , TFETs can have smaller propagation delays compared to CMOS operating in the subthreshold region.