Design structure of tunnel FET by combining thermionic emission with tunneling phenomenon

Abstract

This study proposes a novel electrically doped tunnel field effect transistor (ED-TFET), which combines thermionic emission and band to band tunnelling by using an additional metal source (MS) of appropriate work function (WF; 3.9 eV) by forming an ohmic junction between metal and silicon. The ohmic junction is created below the channel region near the source channel junction by depositing of appropriate workfunction metal (lower than silicon) which injects extra electrons through over the barrier along with band to band tunneling (BTBT) in the channel of the device. Therefore, a drastic improvement in the ON state current is observed which is numerically about 107 times greater than conventional ED-TFET. Furthermore, the radiofrequency figures of merit such cut-off frequency, gain band width product, and maximum oscillating frequency are enhanced by ~10 6 , 20 and 1000 times, respectively, however, intrinsic gain and transconductance generation factor have nearly 66.66 and 14.28% improvement compared to conventional ED-TFET. Furthermore, the concepts of drain underlapping and dual metal gate have been used to checkout OFF-state current and negative conductance as a final proposal. In addition, this study has also investigated the performance variations in the proposed structure due to the WF change of CG2, length of L D1 and position of MS.