Dual Metal Double Gate Ge-Pocket TFET (DMG-DG-Ge-Pocket TFET) with Hetero Dielectric: DC & Analog Performance Projections

Abstract

This work exclusively illustrates dual-metal double gate Ge pocket tunnel field effect transistor (DMG-DG-Ge pocket TFET) with hetero gate dielectric. This structure includes dual-metal gate and hetero-dielectric as well. Extensive TCAD simulation analysis is carried out to illustrate how the device transfer characteristics changes in different regions with respect to various parameters such as, the work-function of tunneling gate and auxiliary gate variations, lengths ratio of tunneling gate and auxiliary gate, and the dielectric constants of homo/hetero dielectrics involved. Here, optimization of dual metal gate work-function is done along with dual gate metal length ratio. To optimize the device behavior hetero gate dielectric HfO2 and SiO2 are considered over the source-channel interface and channel-drain interface, respectively. The enhanced device transfer characteristics obtained are explained and verified with the energy band diagram and tunneling length. The reported device structure achieves ION/IOFF = 5.05 × 1011 and sub-threshold slope (SS) as 15.9425 mV/decade along with the reduced ambipolar current. An increase in ION/IOFF ratio by the order of four as compared to Ge-pocket TFET, is reported with reasonably high ON current for sub 0.5 V supply. This enables the device for low power applications. In addition to this, for the complete analog and RF characterization of the proposed device structure, transconductance, parasitic capacitance, cut-off frequency, intrinsic delay, energy-delay product, transconductance generation factor etc. are also illustrated in detail here. Further, the energy efficiency of the device is also analyzed and justifies for its low power high-speed applications.