The influence of electron-beam irradiation on electrical characteristics of metal-insulator-semiconductor capacitors based on a high-k dielectric stack of HfTiSiO(N) and HfTiO(N) layers

We describe the influence of electron irradiation (at 30 kV with a dose of up to 100 μC/cm²) on the electrical characteristics of metal-insulator-semiconductor structures based on a high-k dielectric stack of HfTiSiO(N) and HfTiO(N). The capacitance-voltage (C-V) and current-voltage characteristics were investigated after irradiation and compared to those of unirradiated samples. To better understand the irradiation effect, the capacitance-voltage (C-V) and current-voltage characteristics were also characterized for structures which were stressed at constant voltages. The irradiation induces a parallel shift of the C-V curves towards negative bias due to the introduction of positive charges in the bulk dielectric and semiconductor-dielectric interface. Annealing at 300 °C restored the C-V characteristics to those of the untreated state. A small decrease of the dielectric constant, from 11.7 to 10.7, was observed after irradiation. No measurable change in leakage current due to irradiation was observed.