Monte Carlo model of resistance evolution in embedded PCM with Ge-rich GST

Abstract

This work presents an optimized model for resistance evolution in PCM cells with Ge-rich GeSbTe (GST) alloy as active material. Unlike conventional Ge2Sb2 Te5, the low-resistance (set) state of Ge-rich GST shows a resistance drift to high resistance R, similar to the high resistance (reset) state, which could be a potential risk for data reliability. We develop a Monte Carlo (MC) model which predicts the time evolution of R at the statistical level of a memory array at various temperature T. The model is validated against variable temperature annealing, such as the soldering profile in embedded PCM, supporting the good reliability of Ge-rich GST at high T.