Improved Drain Current Characteristics of Germanium Source Triple Material Double Gate Hetero-Dielectric Stacked TFET for Low Power Applications

Abstract

In this paper a novel device structure of Triple Material Double Gate (TMDG) SiO2/High-k stacked (Hetero-Dielectric) Tunnel Field Effect Transistor (TFET) with germanium source has been proposed. Three different work function metals over the channel region act as a barrier in the channel which inturn restricts ambipolar effect. Also the concept of hetero-junction at the interface of source to channel region of the proposed device helps to improve the ION current characteristics. The parameters like surface potential, electric field, ION current and IOFF current of the hetero-junction TMDG hetero-dielectric stacked TFET device have been investigated in this work. The proposed device gives an improved ION current and better suppression in leakage current. From the presented results it is found that very low leakage current IOFF (approximately 10−17 A/mm), prominent enhancement in ION current (approximately 10−4 A/mm) and the ION/IOFF current ratio is 1013. Also there is a notable enhancement in ON and OFF current compared with the silicon based TMDG hetero dielectric TFET. The proposed device exhibit unity current-gain cut-off frequency of 50 GHz, while it is 37 GHz for silicon source TMDG hetero-dielectric stacked TFET. 10−17A/mm leakage current confirms the reduced power consumption and 10−4A/mm ON current confirms to speed up the charging and discharging of output capacitance. The results reveal that the germanium source (Hetero-junction) TM-DG Hetero-Dielectric TFET provides better result for Electric field, ION current, IOFF current and ION/IOFF current ratio than the silicon based TM-DG Hetero-Dielectric TFET. The novel proposed device is fitting for low power applications.