Topological insulator Bi2Se3 thin films as an alternative channel material in MOSFETs

TL;DR

This paper investigates Bi2Se3 topological insulator thin films as potential channels in MOSFETs, analyzing their electronic properties and performance limitations through quantum simulations, and highlighting their unique advantages and challenges compared to silicon devices.

Contribution

The study provides the first detailed simulation-based analysis of Bi2Se3 TI thin film MOSFETs, revealing their electrostatic behavior, limitations, and potential for novel device applications leveraging topological properties.

Findings

Bi2Se3 MOSFETs are affected by short-channel effects due to high dielectric constant.

These devices show limitations compared to silicon MOSFETs in performance.

Bi2Se3 MOSFETs may enable novel functionalities using topological surface states.

Abstract

Three-dimensional (3-D) topological insulators (TI) are characterized by the presence of metallic surface states and a bulk band gap. Recently theoretical and experimental studies have shown an induced gap in the surface state bands of TI thin films. The gap results from interaction of conduction band (CB) and valence band (VB) surface states from the opposite surfaces of a thin film, and its size is determined by the film thickness. This gap formation could open the possibility of thin-film TI-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Here we explore the performance of MOSFETs based on TI thin films, specifically Bi2Se3, using quantum ballistic transport simulations with the tight-binding Hamiltonian in the atomic orbital basis. Our simulations indicate that Bi2Se3 MOSFET will be vulnerable to short-channel effects due to the high relative dielectric constant of Bi2Se3(~100)despite its expected excellent electrostatic integrity inherent in a two-dimensional system, and will have other limitations as compared to silicon-based MOSFETs. However, Bi2Se3 MOSFETs, and presumably other TI-based MOSFETs, appear to provide reasonable performance that perhaps could provide novel device opportunities when combined with novel TI properties such as spin-polarized surface states.