Molecular Dynamics Study of Substrate Temperature and Incident Energy Influence on the Crystallization Behavior of Alumina Thin Film Deposition Process

In this study, the method of depositing alumina thin films through magnetron sputtering has been explored using a molecular dynamics approach. The impact of particle incidence energy and substrate temperature on the crystallization behavior of these films was examined. It was found that the crystallization ratio of the films is influenced by the coordination number of atoms. As the incident energy increases, the crystallinity of the deposited films gradually approaches an optimal level. However, surpassing this optimal incident energy leads to irreversible radiation damage, resulting in progressive amorphization. Additionally, it was observed that the optimal energy for ion contribution to the film diminishes with increased substrate temperature. At a substrate temperature of 300 K, the ideal energy for ion transfer to the growing film is found to be 50 eV, which decreases to 40 eV at a temperature of 700 K. The type of film crystallization is primarily in the γ-phase, with the proportion of α-phase diminishing as the incident energy increases. Furthermore, the rate of decrease in α-phase content slows with an increase in temperature. These results were used to analyze the transformation of amorphous to crystalline alumina and to determine the window for the transformation to γ-Al₂O₃. Moreover, the mechanisms of the crystallization process and the transformation of the crystalline morphology were analyzed.