High On-Off Ratio Bilayer Graphene Complementary Field Effect Transistors

TL;DR

This paper introduces a novel dual-gated bilayer graphene FET with doped semiconductor source/drain, achieving high on-off ratios and good scalability, validated through advanced simulations and promising significant improvements over prior devices.

Contribution

It proposes a new S/D engineering approach for bilayer graphene FETs using doped semiconductors, enabling unipolar operation and high on-off ratios.

Findings

On-off ratio exceeds 10^4

Subthreshold slope around 110 mV/decade

Excellent scalability and current saturation

Abstract

In this paper, we propose a novel S/D engineering for dual-gated Bilayer Graphene (BLG) Field Effect Transistor (FET) using doped semiconductors (with a bandgap) as source and drain to obtain unipolar complementary transistors. To simulate the device, a self-consistent Non-Equilibrium Green's Function (NEGF) solver has been developed and validated against published experimental data. Using the simulator, we predict an on-off ratio in excess of $10^4$ and a subthreshold slope of ~110mV/decade with excellent scalability and current saturation, for a 20nm gate length unipolar BLG FET. However, the performance of the proposed device is found to be strongly dependent on the S/D series resistance effect. The obtained results show significant improvements over existing reports, marking an important step towards bilayer graphene logic devices.