A novel self-aligned charge plasma Schottky barrier tunnel FET using work function engineering

Abstract

This paper demonstrates a novel approach to realize highly doped n+ pockets in Schottky barrier tunnel FET (SB-TFET) by inducing charge plasma instead of the actual doping. To induce charge plasma for pocket regions work-function engineering of the gate electrodes is employed. Hence, we investigate a self-aligned double pocket charge plasma Schottky barrier tunnel FET (CP-SB-TFET). The metallurgical realization of these highly doped n+ pockets increases the fabrication complexity as it either requires an epitaxial growth in vertical SB-TFETs or ion implantation in planar SB-TFETs. Here, we propose to realize n+ pockets without the need for a separate implantation, photo masking and higher thermal budget for annealing. Hence, it offers high immunity towards process variations, doping control issues, mobility degradation and random dopant fluctuations (RDFs), while enhancing the inherent advantages of conventional doped device. It synergistically leverages both gate modulated Schottky barrier tunneling and induced electron plasma formation to realize steep sub-threshold slope (SS) behavior, controlled ambipolarity and drain induced barrier lowering (DIBL). Hence, it can be potential candidate for scaled dimensions, fast switching low power applications.