Scaling-down and interfacial effect to break down the trade-off between thermal stability and crystallization speed of the Sb_2Se films

摘要

Phase change memory (PCM) has been one of the most potential technologies for in-memory computing and neuromorphic integrated systems. It requires phase-change memory scaling toward higher density for such applications. However, the scaling-down and interfacial impact in phase-change materials, which are the core of PCMs, are still unclear. In this paper, the phase transition properties and crystallization behavior of phase-change material Sb_2Se were tuned intrinsically by reducing the thickness of the Sb_2Se film and coverage of VO_2. It is shown that the crystallization temperature increases from 209 °C to 224 °C, and 10-year data retention temperature enhances from 117 °C to 139 °C, as the thickness of the Sb_2Se film decreases from 50 nm to 2 nm. The coverage of VO_2 could improve the thermal stability and crystallization rate of the Sb_2Se film obviously, especially for smaller thickness. The kinetic exponent obtained by the JMA model indicates that the crystallization mechanism varies with film thickness, which could tune the crystallization rate of the Sb_2Se film. This study provides a practical solution for on-going optimizing phase-change properties in terms of size and interfacial effects.