Controllable fabrication of highly crystalline and atomically flat phase-change heterostructure thin films

To optimize the crystalline quality of phase-change heterostructure (PCH) thin films and investigate the effects of different substrates and buffer layers on the growth of Sb2Te3 films, we systematically compared the crystalline properties of Sb2Te3 films deposited on Si, SiO2, and Al2O3 substrates. It was found that introducing W or Ti as a buffer layer significantly influences film growth. In particular, the combination of an Al2O3 substrate with W buffer layer approximately 10 nm-thick was shown to markedly promote the high-quality growth of Sb2Te3 films while preserving their orientation consistency. This approach enabled the successful fabrication of PCH films with near-atomic-level flatness. This study provides important experimental evidence and theoretical support for the preparation of high-performance PCH materials.