Electrical characteristics of 60Co γ-ray irradiated MIS Schottky diodes

Abstract

In order to interpret the effect of 60Co γ-ray irradiation dose on the electrical characteristics of MIS Schottky diodes, they were stressed with a zero bias at 1MHz in dark and room temperature during γ-ray irradiation and the total dose range was 0–450kGy. The effect of γ-ray exposure on the electrical characteristics of MIS Schottky diodes has been investigated using C–V and G/ω–V measurements at room temperature. Experimental results show that γ-ray irradiation induces a decrease in the barrier height ΦB and series resistance Rs, decreasing with increasing dose rate. Also, the acceptor concentration NA increases with increasing radiation dose. The C–V characteristics prove that there is a reaction for extra recombination centers in case of MIS Schottky diodes exposed to γ-ray radiation. Furthermore, the density of interface states Nss by Hill–Coleman method increases with increasing radiation dose. Experimental results indicate that the interface-trap formation at high irradiation dose is reduced due to positive charge build-up in the Si/SiO2 interface (due to the trapping of holes) that reduces the flow rate of subsequent holes and protons from the bulk of the insulator to the Si/SiO2 interface.