A High-Performance Inverted-C Tunnel Junction FET With Source–Channel Overlap Pockets

Abstract

In this paper, we propose and simulate a new structure of a line tunnel FET employing gate over source-channel overlap pockets (GO-SCOPs). The SCOPs create vertical tunneling path within the source and the channel extension that lead to a faster thinning of the lateral tunneling barrier between the source and channel regions. As a result, an inverted C-shaped tunnel junction is formed providing both lateral tunneling and vertical tunneling. A calibrated 2-D simulation study shows that an ON-current improvement by one order is achieved in comparison with the gate over source only (GoSo) tunnel field-effect transistors with pockets. Further, the OFF-state leakage and average subthreshold swing are reduced by 44% and 21%, respectively, with an improved parasitic capacitance. This has improved the cutoff frequency from 8.3 MHz in GoSo with pockets structure to 1.19 GHz in the proposed GO-SCOP structure. Furthermore, by employing Ge SCOPs, the ON current is boosted by 4 orders of magnitude, maintaining leakage at ~0.25 fA/μm, giving ION/IOFF > 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> , and a much improved average subthreshold swing of ~48 mV/dec at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</sub> = 2 V, V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> = 0.5 V.