Phase change behavior improvement of Sb₂Te₃films by Si doping: Raman scattering evidence at elevated temperatures

The dynamic crystallization process of silicon (Si) doped Sb2Te3 (SST) films as a function of temperature (210-620 K) and Si concentration (0%-12%) has been investigated by temperature dependent Raman scattering. Based upon the evolution of original Raman spectra and surface morphologies with increasing temperature for the samples, it can be concluded that the temperature ranges for intermediate transition states are estimated to be 160, 120, and 80 K, corresponding to SST7%, SST9%, and SST12% films, respectively. This phenomenon can also be summarized by the thermal evolution of the proportion of the rhombohedral phase derived from Raman phonon modes. It illustrates that Si introduction can suppress the crystallization of amorphous films, increase the crystallization temperature, and accelerate the crystallization process of the intermediate transition state. The phase change behavior improvement by Si doping is of great significance for further study on the amorphous thermal stability and endurance of SST-based data storage devices from the optical perspective.