Modeling of a vertical tunneling graphene heterojunction field-effect transistor

TL;DR

This paper models a vertical tunneling graphene heterojunction FET using quantum transport simulations, revealing how work function differences and electrostatic effects influence device behavior and scaling.

Contribution

It introduces a self-consistent quantum transport simulation approach to analyze the electrical characteristics of vertical graphene heterojunction FETs.

Findings

Asymmetric p- and n-type conduction due to work function differences

Modulation of bottom-graphene contact affects switching behavior

Output I-V characteristics do not saturate due to short-channel effects

Abstract

Vertical tunneling field-effect-transistor (FET) based on graphene heterojunctions with layers of hBN is simulated by self-consistent quantum transport simulations. It is found that the asymmetric p-type and n-type conduction is due to work function deference between the graphene contact and the tunneling channel material. Modulation of the bottom-graphene-contact plays an important role in determining the switching characteristic of the device. Due to the electrostatic short-channel-effects stemming from the vertical-FET structure, the output I-V characteristics do not saturate. The scaling behaviors the vertical-FET as a function of the gate insulator thickness and the thickness of the tunneling channel material are examined.