Flexible semi-around gate silicon nanowire tunnel transistors with a sub-kT/q switch

Abstract

Tunnel field-effect transistors (TFETs) with a subthreshold swing (SS)< 60 mV/dec are expected to be active devices in low-power flexible systems, potentially lowering operational voltage by virtue of steep switching behavior via band-to-band tunneling. In silicon (Si) channel materials, however, it still remains a challenge to obtain SS smaller than 60 mV/dec. In this study, we experimentally demonstrate the sub-60 mV/dec operation of a flexible semi-around gate TFET on a plastic substrate using Si nanowires (SiNWs) as the channel material. With the combined advantages of selectively thinned SiNW channels (width similar to 15 nm and height similar to 40 nm) and high-kappa (Al2O3 similar to 7 nm) gate dielectric, in conjunction with an abrupt degenerate source junction, the device with a channel length of similar to 500 nm exhibits a minimal SS of similar to 42 mV/dec at room temperature. Moreover, mechanical bendability of the device indicates that it has stable and good fatigue properties, providing an important step towards the realization of steep-slope switches for low-power and energy-efficient flexible electronics. (C) 2015 AIP Publishing LLC.