The electrical and dielectric properties of the Al/SiO2/p-Si (MIS) Schottky diodes have been investigated by capacitance-voltage (C-V) and conductance-voltage (G/omega-P) measurements in the frequency (f) and temperature (T) range of 100 Hz-1 MHz and 80-300 K, respectively. Experimental results show that the values of dielectric constant (epsilon'), dielectric loss (epsilon"), loss tangent (tan delta), ac electrical conductivity (sigma(ac)) and the electric modulus were found to be a strong function of T and f. An increase in the values of the epsilon' and epsilon" was observed with both a decrease in frequency and an increase in temperature. The sigma(ac) is found to increase with both increasing frequency and temperature. In addition, the experimental dielectrical data have been analyzed considering electric modulus formalism. The interfacial polarization can more easily occur at the lower frequency and/or with the number of interface state density between Si/SiO2 interface, consequently, which contributes to the improvement of dielectric properties of MIS Schottky diode. (c) 2006 Elsevier B.V. All rights reserved.