Controlling ambipolar current of dopingless tunnel field-effect transistor

Abstract

Ambipolarity in tunnel field-effect transistor (TFET) is a subject of grave concern in the current scenario of the semiconductor industry as this property of device limits its usability in CMOS circuit applications. In this concern, this paper presents a new approach to suppress the ambipolar behavior of dopingless TFET (DL TFET) by controlling the lateral band-to-band tunneling at the drain/channel interface. To execute this, a metal strip is embedded inside the oxide region between gate and drain terminals to modulate the energy bands for preventing the tunneling of charge carriers. The energy bands are widened at the drain-channel junction using this technique and correspondingly ambipolarity is reduced by a factor of $$10^{11}$$ . The variation in the energy bands is examined under different negative gate bias for the proposed device and conventional device which has shown that the energy barrier for the proposed device remains wider for different voltages under the influence of metal embedded. Alignment of the metal strip is varied to obtain the desired performance of the device. In this regard, optimization of work function and length of metal strip along with its position is demonstrated considering its impact on the ambipolar current and ON-state current, which gave 4.0 eV work function and 20 nm as the optimized work function and length of the metal strip, respectively.