On the profile of 60''Co γ-ray irradiation dependent interface states and series resistance in Al/SiO₂/p-Si (Mis) structures

The effect of γ-ray exposure on the Al/SiO₂/p-Si (Mis) structures has been investigated using the current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G/w-V) characteristics at room temperature. The MIS structures are irradiated with 60''Co γ-ray source, with a dose rate of 1.12 kGy/h and an over dose range from 0 kGy to 5 kGy. The ideality factor (n) increases with irradiation dose due to an increase radiation induced interface states (N_ss). The density of N_ss distribution profiles as a function E_ss-E_v was extracted from the forward bias I-V characteristics taking into account the bias dependence of the effective barrier height (Φ_e). The values of N_ss showing an experimental decrease with bias from the top of the valance band towards the mid gap. In addition, C-V and G/w-V characteristics of MIS structures show fairly large radiation dispersion. The series resistance (R_s) profile of MIS structures was extracted from the measured C_m and G_m/w measurements according to admittance method and its value increases with increasing dose. Experimental results show that γ-ray irradiation have a significant effect on electrical characteristics of MIS Structures.