Strain Engineering for High-Performance Phase Change Memristors

TL;DR

This paper demonstrates a strain-engineered 2D memristor using multilayer MoTe2 that surpasses existing devices in performance metrics like on/off ratio and switching speed, achieved through process-induced strain and phase transition control.

Contribution

It introduces a novel strain engineering method to enhance phase change memristor performance in 2D materials without forming steps, enabling ultra-low voltage and high-speed switching.

Findings

Achieved >10^8 on/off ratio in 2D memristors.

Realized 5 ns switching speed with retention over 10^5 seconds.

Controlled device tunability via contact metal film stress.

Abstract

A new mechanism for memristive switching in 2D materials is through electric-field controllable electronic/structural phase transitions, but these devices have not outperformed status quo 2D memristors. Here, we report a high-performance bipolar phase change memristor from strain engineered multilayer 1T'-MoTe$_{2}$ that now surpasses the performance metrics (on/off ratio, switching voltage, switching speed) of all 2D memristive devices, achieved without forming steps. Using process-induced strain engineering, we directly pattern stressed metallic contacts to induce a semimetallic to semiconducting phase transition in MoTe2 forming a self-aligned vertical transport memristor with semiconducting MoTe$_{2}$ as the active region. These devices utilize strain to bring them closer to the phase transition boundary and achieve ultra-low ~90 mV switching voltage, ultra-high ~10$^8$ on/off ratio, 5 ns switching, and retention of over 10$^5$ s. Engineered tunability of the device switching voltage and on/off ratio is also achieved by varying the single process parameter of contact metal film force (film stress $\times$ film thickness).