Effects of gamma irradiation on electrical parameters of metal–insulator–semiconductor structure with silicon nitride interfacial insulator layer

Abstract

The effects of gamma irradiation on electrical parameters of Au/Si₃N₄/n-Si (MIS) structure were investigated by using the capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements. The MIS structure was irradiated using gamma-radiation source at a dose rate of 0.69 kGy/h. The C–V and G/ω–V measurements were carried out at a total dose range of 0–100 kGy for five different frequencies (1, 10, 100, 500 and 1000 kHz). The obtained results showed that the C and G/ω values decrease with the increasing radiation dose due to the irradiation-induced defects at the interface. Also, the observed decrease in the C and G/ω values with the increasing frequency was explained on the basis of interface states (N_ss). The values of series resistance (R_s) increase with the increasing radiation dose. To obtain the real capacitance and conductance of the capacitor, the measured values of C and G/ω were corrected to eliminate the effect of series resistance. The values of N_ss were determined by using the conductance method and were decreased with the increasing radiation dose.

Keywords:

• MIS structure
• radiation effects
• interface states
• series resistance