Design and Sensitivity Analysis of Steep-Slope Bi-Channel Vertical Tunnel Field Effect Transistor

Abstract

In this paper, the electrical characteristics of a low power steep-slope vertical tunnel field effect transistor (VTFET) is introduced with dual lateral channel in the source sidewall, which can considerably improve the device performance in comparison with the planar tunnel field effect transistor (TFET). The results demonstrate that unlike the conventional TFET with limited tunneling junction at the source/channel interface, the band to band tunneling area in VTFET is created along the entire length of the source region from the both sides, which amplifies the tunneling rate. The results demonstrate that on/off current ratio of 8.36e+7 and subthreshold swing (SS) of 10 mV/dec has been achieved for the VTFET in comparison with the on/off current ratio of 9.79e+5 and SS = 31 mV/dec for the planar TFET, respectively. Sensitivity analysis is conducted via calculating the standard deviation and mean value of main electrical measures as a function of various design parameters. It is indicated that gate workfunction and source doping density are critical design parameters that may fundamentally affect the efficiency of the device. An important feature of the proposed device is the insensitivity of the off-state current and subthreshold swing to the channel length scaling and drain bias, which exhibits VTFET promising potential for future low-power circuits.