Understanding the impact of energetic ion irradiation on semiconductor materials and devices is essential for optimizing their electronic applications. This knowledge contributes to the broader goal of tailoring material properties to enhance the overall performance and reliability of semiconductor devices. In this study, we investigate the impact of 1.2 MeV Ar8+ irradiation on Au/n-Si Schottky barrier structures in-situ, as a function of ion irradiation fluence. Electrical characterization was performed in-situ on a single sample to mitigate any variability in device parameters between samples. It is observed that ion irradiation results in an increased Schottky barrier height with a reduction in reverse leakage current. The behavior is attributed to dopant deactivation by the energetic ion irradiation-induced defects near the interface. These results underscore the importance of understanding ion irradiation impacts on semiconductor devices, providing valuable insights for optimizing Schottky diodes in electronic applications.