Multi-Physics Modeling Of Phase Change Memory Operations in Ge-rich Ge$_2$Sb$_2$Te$_5$ Alloys

TL;DR

This paper develops a comprehensive multi-physics model combining phase-field and electro-thermal simulations to better understand phase change memory operations in Ge-rich Ge$_2$Sb$_2$Te$_5$ alloys, aligning simulations with experimental data.

Contribution

It introduces a combined multi-physics modeling approach for PCM that integrates phase change and electro-thermal effects, improving accuracy over previous simplified models.

Findings

Model accurately reproduces experimental calibration curves.

Simulations demonstrate effective memory operation predictions.

Enhanced understanding of Ge-rich GST phase change behavior.

Abstract

One of the most widely used active materials for phase-change memories (PCM), the ternary stoichiometric compound Ge$_2$Sb$_2$Te$_5$ (GST), has a low crystallization temperature of around 150$^\circ$C. One solution to achieve higher operating temperatures is to enrich GST with additional germanium (GGST). This alloy crystallizes into a polycrystalline mixture of two phases, GST and almost pure germanium. In a previous work [R. Bayle et al., J. Appl. Phys. 128, 185101 (2020)], this crystallization process was studied using a multi-phase field model (MPFM) with a simplified thermal field calculated by a separate solver. Here, we combine the MPFM and a phase-aware electro-thermal solver to achieve a consistent multi-physics model for device operations in PCM. Simulations of memory operations are performed to demonstrate its ability to reproduce experimental observations and the most important calibration curves that are used to assess the performance of a PCM cell.