Engineering Neuromorphic Phase-Change Memory: Carbon-Doped GeSbTe with High Thermal Stability and Low Resistance Drift

Phase-change memory (PCM) has emerged as a promising non-volatile memory technology, offering significant potential for next-generation artificial intelligence and neuromorphic computing systems. However, conventional Ge1Sb4Te7 (GST), a prototypical stoichiometric phase-change chalcogenide, suffers from intrinsic limitations such as inadequate thermal stability and pronounced resistance drift, hindering its practical applications in high-performance devices and chips. In this study, we demonstrate that carbon (C) doping in GST markedly enhances its thermal robustness and data retention, while elucidating the underlying microstructure-property relationships. Carbon doping significantly increases the crystallization temperature of GST, shifting it to and beyond 200 ℃ with increasing carbon content. Higher carbon incorporation also yields up to a fourfold improvement in data retention, achieving 10-year stability at 100 ℃. Moreover, GST-C-based PCM devices exhibit excellent electrical stability, featuring ultralow resistance drift (ν = 0.03) and highly reproducible multilevel resistance states. Through ab initio simulations, we uncover the atomic-scale mechanisms governing these enhancements: carbon incorporation induces the formation of robust, shortened bonds with Ge/Sb/Te, promoting tetrahedral C clusters that impede crystallization by elevating the activation energy barrier. This work identifies GST-C as a promising candidate for reliable, high-density PCM and highlights its potential for neuromorphic computing applications.