Non-Monotonic $\gamma$ -Ray Influence on Mo/n-Si Schottky Barrier Structure Properties

The current-voltage characteristics of Mo/n-Si Schottky barrier structure irradiated by γ-rays of ⁶⁰Co were investigated in the temperature range of 120-330 K. The zero-bias barrier height, ideality factor, and reverse current were found to depend non-monotonously on the cumulative dose. The samples exposed to different radiation doses were found to display different forward current transport mechanism. In non-irradiated structure the current-transport mechanism is thermionic emission (TE) over inhomogeneous barrier. In the structure exposed to 10 kGy the mechanism is defect-assisted tunneling in the lower temperature range 120-220 K, and TE over inhomogeneous barrier in the higher temperature range 260-330 K. In the structure exposed to 100 kGy the mechanism is tunneling in the 150-220 K range, and TE (dominant) and tunneling at 260-330 K. The obtained results are explained by the increase of radiation defect concentrations (for comparatively small doses), and by further gettering of defects in the inhomogeneous regions as the irradiation dose increases.