The effect of the C-60(o) (gamma-ray) exposure oil the electrical characteristics of Al/SiO2/p-Si (MIS) structures has been investigated using capacitance-voltage (C - V) and conductance-voltage (G/omega - V) measurements. The MIS structures were stressed with a bias of 0 V during C-60(o) gamma-sources irradiation with the total dose range from 0 to 25 kGy. The C - V and G/omega - V characteristics were measured at 500 kHz and room temperature before and after C-60(o) gamma-ray irradiation. The results indicated that gamma-irradiation caused an increase in the barrier height Phi(B), interface states N-SS and depletion layer width W-D obtained from reverse bias C - V measurements. The series resistance R-S profile for various radiation closes was obtained from forward and reverse bias C - V and G/omega - V measurements. Both C - V and G/omega - V characteristics indicate that the total dose radiation hardness of MIS structures may be limited by the decisive properties of the SiO2/Si interface to radiation-induced damage. After gamma-irradiation, the decrease in capacitance of MIS structure results in the increase in the semiconductor depletion width. (c) 2008 Elsevier B.V. All rights reserved.