Monolithic TCAD Simulation of Phase-Change Memory (PCM/PRAM) + Ovonic Threshold Switch (OTS) Selector Device

TL;DR

This paper presents a comprehensive monolithic TCAD simulation of phase-change memory (PCM) and Ovonic Threshold Switch (OTS) devices, validating models against experimental data and demonstrating integrated device behavior within a single simulation framework.

Contribution

It introduces the first monolithic simulation of both PCM and OTS devices in a single TCAD framework, enabling better material and device design insights.

Findings

PCM model matches experimental data

OTS behavior simulated qualitatively

Integrated PCM+OTS simulation performed successfully

Abstract

Owing to the increasing interest in the commercialization of phase-change memory (PCM) devices, a number of TCAD models have been developed for their simulation. These models formulate the melting, amorphization and crystallization of phase-change materials as well as their extreme conductivity dependence on both electric field and temperature into a set of self-consistently-solved thermoelectric and phase-field partial-differential equations. However, demonstrations of the ability of such models to match actual experimental results are rare. In addition, such PCM devices also require a so-called selector device - such as an Ovonic Threshold Switching (OTS) device - in series for proper memory operation. However, monolithic simulation of both the PCM and OTS selector device in a single simulation is largely absent from the literature, despite its potential value for material- and design-space explorations. It is the goal of this work to first characterize a PCM device in isolation against experimental data, then to demonstrate the qualitative behavior of a simulated OTS device in isolation and finally to perform a single monolithic simulation of the PCM + OTS device within the confines of a commercially available TCAD solver: GTS Framework.