Impact of CF₄ plasma etching on defect formation and material properties of Al₂O₃ thin films

Abstract Fluorine-based plasma etching of Al 2 O 3 induces changes in oxygen vacancy concentrations and aluminum bond modifications, which affect the electrical properties of the thin film, leading to increased leakage currents and the formation of charge traps that degrade the device reliability. Therefore, in this study, we systematically examined the effects of CF 4 plasma etching on the structural, optical, and electrical properties of Al 2 O 3 thin films, focusing on defect dynamics during processing. X-ray photoelectron spectroscopy analysis demonstrated that Al-O to Al-F bond conversion occurred during plasma etching, resulting in modified oxygen vacancy concentrations. Chemical modifications induced changes in the optical bandgap and work function with increasing radiofrequency bias power, indicating a change in the electronic band structure. Dielectric measurements indicated reduction in dielectric constant due to Al-F bond formation. These results elucidate the relationship between plasma-induced defects, including both defect generation and atomic substitution by plasma, contributing to the development of high-quality Al 2 O 3 thin films for electronic applications in the future.