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.