Gamma-ray irradiation effects on the interface states of MIS structures

Abstract

Gamma-ray irradiation effects on the interface states of Au/SiO 2/n-Si (MIS) structures have been determined from capacitance–voltage ( C– V) and conductance–voltage ( G/ ω– V) measurements. The MIS structures were irradiated with gamma-rays at doses up to 100 kGy. The C–V and G/ ω– V characteristics were measured at high frequency (1 MHz) and room temperature before and after 60Co γ-ray irradiation. The obtained results showed that the barrier height ( Φ b) decreases with increasing radiation dose, while the interface states ( N ss) and depletion layer width ( W D) increase with the increase in radiation dose obtained from reverse bias C– V measurements. After γ irradiation, the decrease in capacitance and conductance of MIS structure result in the increase in the semiconductor depletion width. In addition, the voltage dependency of the series resistance ( R s) profile for various radiation doses was obtained from admittance-based measurement method. In addition, the high frequency (1 MHz) capacitance and conductance values measured under both reverse and forward bias have been corrected for the effect of R s to obtain the real capacitance of MIS structure. Experimental results indicate that the total dose radiation hardness of MIS structures may be limited by the decisive properties of the SiO 2/Si interface to radiation-induced damage.