Double Gate TFET with Germanium Pocket and Metal drain using Dual Oxide

A detailed and thorough study has been carried out to realize the working of our proposed device which is a Germanium (Ge) pocket based Tunnel Field Effect Transistor (TFET). The proposed device employs a germanium pocket near the source channel junction of the double-gate TFET. Germanium, being a low bandgap material, increases the transmission rate of electrons at the tunneling junction and hence improves the ON state performance of the device. The proposed TFET also uses a dual oxide, with hafnium oxide (HfO2) near the source side and silicon dioxide (SiO2) near the drain. The use of Ge pocket and the dual oxide improve the characteristics of our proposed TFET significantly. Another objective of this work is to eliminate the ambipolarity problem, which has been dealt with by using a metallic drain in place of the conventional material. Two dimensional (2D) calibrated simulations have shown a doubling of ON current (ION), two orders increase in ION/IOFF ratio, ambipolarity suppression and steep subthreshold slope (SS) of 30 mV/dec in the proposed device in comparison to the conventional TFET. The device works at an operating voltage of 0.4V with gate voltage varying from -0.6V to +0.6V. Further simulations have been carried out to improve the performance of the proposed device by optimizing various other device parameters.