Coherent Structure in Indium Doped Phase Change Materials

Phase change memory (PCM) technology demonstrates significant potential as a next-generation non-volatile storage solution for information applications. Ge₂Sb₂Te₅ (GST) alloy, the most well-established material employed in commercial PCM devices, exhibits limited thermal stability. Doping, as an effective approach for enhancing thermal stability, often induces element segregation and phase separation. This study systematically investigates the impact of indium (In) doping on GST phase-change material. Experimental results demonstrate that In doping significantly enhances the thermal stability of GST film. In17GST exhibits a 130 °C increase in crystallization temperature (from 181 °C to 311 °C). Especially, the introduction of In leads to the formation of In₂Te₃ phase, which exhibits a remarkably similar crystal structure to GST with only a ~2% lattice mismatch. Consequently, In₂Te₃ phase forms a coherent structure with GST lattice, thereby promoting the stability of the phase boundary. Additionally, In₂Te₃ phase facilitates efficient heating with a 5.7% improvement in heating efficiency (913 K vs. 864 K at 5 ns) and contributes to improved RESET operations in PCM devices. Our study lays the foundation for the composition and structure design for high thermal stability and low power consumption in PCM devices.