Strain-Based Room-Temperature Non-Volatile MoTe$_2$ Ferroelectric Phase Change Transistor

TL;DR

This paper demonstrates a room-temperature, non-volatile ferroelectric phase change transistor using strain engineering in MoTe$_2$, enabling ultra-fast, low-power switching that overcomes limitations of traditional field-effect transistors.

Contribution

It introduces a novel strain-based switching mechanism in MoTe$_2$ transistors that achieves large non-volatile conductivity changes at room temperature, bypassing power and speed limitations of conventional FETs.

Findings

Achieved G$_{on}$/G$_{off}$ ratio of ~10$^7$ using strain-induced phase change.

Demonstrated reversible switching between semimetallic and semiconducting phases.

Operates at room temperature with potential for sub-ns, attojoule/bit non-volatile switching.

Abstract

The primary mechanism of operation of almost all transistors today relies on electric-field effect in a semiconducting channel to tune its conductivity from the conducting 'on'-state to a non-conducting 'off'-state. As transistors continue to scale down to increase computational performance, physical limitations from nanoscale field-effect operation begin to cause undesirable current leakage that is detrimental to the continued advancement of computing. Using a fundamentally different mechanism of operation, we show that through nanoscale strain engineering with thin films and ferroelectrics (FEs) the transition metal dichalcogenide (TMDC) MoTe$_2$ can be reversibly switched with electric-field induced strain between the 1T'-MoTe$_2$ (semimetallic) phase to a semiconducting MoTe$_2$ phase in a field effect transistor geometry. This alternative mechanism for transistor switching sidesteps all the static and dynamic power consumption problems in conventional field-effect transistors (FETs). Using strain, we achieve large non-volatile changes in channel conductivity (G$_{on}$/G$_{off}$~10$^7$ vs. G$_{on}$/G$_{off}$~0.04 in the control device) at room temperature. Ferroelectric devices offer the potential to reach sub-ns nonvolatile strain switching at the attojoule/bit level, having immediate applications in ultra-fast low-power non-volatile logic and memory while also transforming the landscape of computational architectures since conventional power, speed, and volatility considerations for microelectronics may no longer exist.