Vertical InAs-Si gate-all-around tunnel FETs integrated on Si using selective epitaxy in nanotube templates

Abstract

In this paper, we introduce ${p -channel InAs-Si tunnel field-effect transistors (TFETs) fabricated using selective epitaxy in nanotube templates. We demonstrate the versatility of this approach, which enables III-V nanowire integration on Si substrates of any crystalline orientation. Electrical characterization of diodes and of TFETs fabricated using this method is presented; the TFETs exhibit a good overall performance with on-currents, ${I} -{\rm on of 6 μ A/ μ m ( $|V-{GS}| = |V-{DS}| = 1$ V) and a room-temperature subthreshold swing (SS) of $\sim 160$ mV/dec over at least three orders of magnitude in current. Temperature-dependent measurements indicate that SS is limited by traps. We demonstrate improved TFET ${I} -{\rm on performance by 1-2 orders of magnitude by scaling the equivalent oxide thickness from 2.7 to 1.5 nm. Furthermore, a novel benchmarking scheme is proposed to allow the comparison of different TFET data found in literature despite the different measurement conditions used.