Liquid Metal Printed Ultrathin Oxides for Monolayer WS2 Top-Gate Transistors

TL;DR

This paper introduces a scalable liquid metal printing method to create ultrathin Ga2O3 dielectrics for 2D WS2 transistors, achieving atomically smooth interfaces, low EOT, and low leakage for advanced nano-electronics.

Contribution

The study presents a novel liquid metal printing technique for ultrathin Ga2O3 dielectrics compatible with 2D materials, enabling improved device performance.

Findings

Achieved EOT of ~1 nm in 2D transistors.

Demonstrated atomically smooth Ga2O3/WS2 interfaces.

Gate leakage currents meet low-power circuit requirements.

Abstract

Two-dimensional (2D) semiconductors are promising channel materials for continued downscaling of complementary metal-oxide-semiconductor (CMOS) logic circuits. However, their full potential continues to be limited by a lack of scalable high-k dielectrics that can achieve atomically smooth interfaces, small equivalent oxide thicknesses (EOT), excellent gate control, and low leakage currents. Here, we report liquid metal printed ultrathin and scalable Ga2O3 dielectric for 2D electronics and electro-optical devices. We directly visualize the atomically smooth Ga2O3/WS2 interfaces enabled by the conformal nature of liquid metal printing. We demonstrate atomic layer deposition compatibility with high-k Ga2O3/HfO2 top-gate dielectric stacks on chemical vapour deposition grown monolayer WS2, achieving EOTs of ~1 nm and subthreshold swings down to 84.9 mV/dec. Gate leakage currents are well within requirements for ultra-scaled low-power logic circuits. Our results show that liquid metal printed oxides can bridge a crucial gap in scalable dielectric integration of 2D materials for next-generation nano-electronics.