A device-level compact model for mushroom-type phase change memory

TL;DR

This paper presents a new compact device-level model for mushroom-type phase change memory that accurately predicts programming, switching, and read-out behaviors by considering shape, size, and leakage paths, and is compatible with circuit simulations.

Contribution

The model uniquely incorporates shape, size, and leakage paths of phase configurations, enabling precise simulation of device behaviors in circuit-level applications.

Findings

Accurately modeling phase shape and size is crucial for predicting programming characteristics.

The model captures resistance drift and current asymmetry behaviors.

Verilog-A implementation facilitates integration into circuit simulations.

Abstract

In this work we introduce a compact model for mushroom-type phase-change memory devices that incorporates the shape and size of the amorphous mark under different programming conditions, and is applicable to both projecting and non-projecting devices. The model includes analytical equations for the amorphous and crystalline regions and uniquely features a current leakage path that injects current at the outer edge of the electrodes. The results demonstrate that accurately modeling the size and shape of the phase configurations is crucial for predicting the full-span of the RESET and SET programming, including the characteristics of threshold switching. Additionally, the model effectively captures read-out behaviors, including the dependence of resistance drift and bipolar current asymmetry behaviours on the phase configurations. The compact model is also provided in Verilog-A format, so it can be easily used in standard circuit-level simulation tools.