DC Performance Analysis of Heterojunction Tunnel FET by Optimizing Various High-κ Materials: HfO2/ZrO2 with Low/High-κ Spacer

Abstract

In this study, double gate tunnel field effect transistor with heterojunctions have been investigated by various III-V compound semiconductor materials using 2-D Technology Computer Aided Design (TCAD) simulations. Firstly, 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. Secondly, high-κ/low-κ spacer is incorporated beside the channel-source and channel-drain region for better tunneling along the surface. 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, achieves of ION (max.) as 1.52 × 10−5 A/µm. further with low-κ spacer engineering, the subthreshold swing (ss) has also been recorded best as 19.76 mV/decade in comparison with conventional HTFET structures, can serve as better alternative tunnel FETs in low power logic applications.