Electrical Characteristics Assessment on Heterojunction Tunnel FET (HTFET) by Optimizing Various High-κ Materials: HfO2/ZrO2

Abstract

In this paper, DC performance of double gate tunnel field effect transistor with heterojunction has been assessed by various III-V compound semiconductor materials using 2-D Technology Computer Aided Design (TCAD) simulations. Different hetero high-κ dielectric materials like HfO2, ZrO2 have been incorporated to achieve better electrical characteristics, viz. high ON-state current drivability, improved switching ratio and high tunneling probability. In this work, lower band gap materials have been used as hetero gate dielectric to enhance mobility using band to band tunneling (BTBT), transconductance and steeper subthreshold-slope. The heterojunction TFET (HTFET) then incorporated with various hetero dielectrics (high-κ and low-κ combination), where the ZrO2 – SiO2 combination of dielectric having thickness of 2 nm both in front and back gate, attains maximum value of ION as 1.522 × 10-5 A/μm. The subthreshold swing (ss) has also been recorded best as 23.93 mV/dec in comparison with conventional homo dielectric i.e. SiO2-SiO2 oxide throughout the 50 nm channel of HTFET as 34.22 mV/dec, can serve as better alternative tunnel FETs in low power logic applications.