To determine the dielectric constant dielectric loss (epsilon"), loss tangent (tan delta), the ac electrical conductivity (sigma(ac)) and the electric modulus of Au/SiO(2)/n-Si structure, the measurement admittance technique was used. Experimental results show that the values of epsilon', epsilon", tan delta, sigma(ac) and the electric modulus show fairly large frequency and gate bias dispersion especially at low frequencies due to the interface charges and polarization. An increase in the values of the epsilon' and epsilon" were observed with both a decrease in frequency and an increase in frequency. The a,c is found to increase with both increasing frequency and voltage. In addition, the experimental dielectrical data have been analyzed considering electric modulus formalism. It can be concluded that the interface charges and interfacial polarization have strong influence on the dielectric properties of metal-insulator-semi conductor (MIS) structures especially at low frequencies and both in depletion and accumulation regions. (C) 2008 Elsevier B.V. All rights reserved.