The temperature (T) dependence of electrical and dielectric characteristics such as series resistance (R-s), dielectric constant (epsilon'), dielectric loss (epsilon ''), dielectric loss tangent (tan delta), and real and imaginary pan of electrical modulus (M' and M '') of the Au/SiO2/n-GaAs (MOS) structures have been investigated in the temperature range of 80-350 K at various frequencies by using experimental capacitance (C) and conductance (G/w) measurements. Experimental results show that both C and G/w characteristics were quite sensitive to frequency and temperature at especially high temperatures and low frequencies due to a continuous density distribution of interface states and their relaxation time, and thermal restructuring and reordering of the inter-face. Series resistance values of this device obtained from Nicollian method decrease with increasing frequency and temperature. The epsilon', epsilon '', tan delta, and M' and M '' were found a strong function of frequency and temperature. While the values of epsilon', epsilon '', and tan delta decrease, M' and M '' increase with increasing frequency. Also, while epsilon' and epsilon '' increase, M' and M '' decrease with increasing temperature. The tan delta and M' values are almost independent temperature especially at high frequencies (f >= 500 kHz). (C) 2009 Elsevier B.V. All rights reserved.