Crystallization kinetics of Sb70Se30 thin films for phase change memories under the non-isothermal conditions

Abstract

We investigate the non-isothermal crystallization kinetics of Sb70Se30 thin films using differential scanning calorimetry and determine the kinetic triplet of Sb70Se30 thin films at various heating rates by combining model-free and model-fitting approaches. The results indicate that the crystallization activation energy decreases with increasing crystallization fraction α, confirming the presence of multi-step crystallization mechanism. In accordance with the local Avrami index n(α), the crystallization mechanism shifts from three-dimensional growth with an increased nucleation rate at 0.05 ≤ α ≤ 0.8 to three- and two-dimensional growth with a reduced nucleation rate at α＞0.8. Afterwards, we deduce that the Sb70Se30 thin films follow a second-order reaction model within the heating rate range of 20 to 40 K/min. Moreover, the Sb70Se30 thin film shows excellent data retention capability when predicting data processing and data storage time based on phase change memory units. These findings provide valuable insights into the crystallization kinetics of Sb70Se30 thin films, contributing to the advancement of phase change materials.