The enhanced thermal stability of single element Sb phase-change materials by rare earth

Sb-based single-element phase-change memory exhibits exceptional potential for next-generation phase-change memory (PCM) applications, owing to its fast phase transition capability and remarkably low resistance drift coefficient. However, it is significantly hindered by its inadequate thermal stability, making it susceptible to spontaneous crystallization at ambient temperature. This research details the production of Sb-Yb composite films utilizing magnetron sputtering techniques, along with an in-depth analysis of their crystallization processes. The Sb-based composite film exhibits high crystallization temperature (120 °C), the Growth-dominated crystallization mode (n_avg = 0.96), low resistance drift (0.015), and enhanced optical bandgap (0.91 eV). These advancements are attributed to a unique crystalline-amorphous nanocomposite structure, where Sb nanograins (10–20 nm) are encapsulated by an amorphous Sb-Yb phase. The amorphous Yb-Sb matrix refines grain size and suppresses excessive growth of Sb nanograins, thereby significantly enhancing the structural thermal stability. This nanocomposite architecture significantly enhances thermal stability in Sb-based PCMs while exhibiting extremely low resistance drift and maintaining the growth-type crystallization mechanism, effectively overcoming the limitations of pure Sb and traditional Ge₂Sb₂Te₅ (GST) materials.