Device and circuit performance evaluation and improvement of SiGe Tunnel FETs

Investigation on Tunnel FETs in recent years have proved them to be better than conventional MOSFETs lower subthreshold swing, lower power consumption and their scaling is not limited by quantum mechanical effects [1]. Improvement in the on-current of TFETs has been proposed by the use of SiGe layer on the source side [2]. This paper investigates the effect of different Ge mole fractions on the performance of various benchmark circuits (inverter, inverter with constant load, 8 bit ripple carry adder (RCA), 5 stage ring oscillator, 10 stage NAND and NOR chain). A method of the Ion/Ioff ratio of TFETs with high Ge composition, by grading the Ge composition has also been suggested.