Approach to suppress the ambipolar current conduction and improve radiofrequency performance in polarity control electrically doped hetero TFET

Abstract

In this work, a distinctive approach for the suppression of ambipolar behaviour of novel polarity control electrically doped hetero tunnel field effect transistor (TFET) has been reported. For this purpose, a wider band gap material, gallium arsenide phosphide has been employed at drain/channel regions. However, narrow band-gap material, silicon has been used in the source region. This combination of materials leads to a huge reduction in the ambipolar current and significant improvement in ON-state current due to the reduction in the electric field at the drain/channel interface and improvement in tunnelling rate at the source/channel interface, respectively. The proposed device also reduces the drain to source capacitance due to the presence of potential barrier width which leads to improvement in the radiofrequency performance. Therefore, the proposed device is very useful for ultralow power circuit applications. Moreover, polarity gates (PG1 and PG2) have been considered for the formation of n+ (drain) and p+ (source) regions. Hence, the proposed structure avoids ion implantation, random doping fluctuation, and high thermal budget unlike in the case of conventional TFETs, as the latter is physically doped. All the simulations have been performed using ATLAS software.