The temperature dependence of capacitance-voltage (C-V) and conductance-voltage (G/w-V) characteristics of Al/HfO2/p-Si metal-oxide-semiconductor (MOS) device has been investigated by considering the effect of series resistance (R-s) and interface state density (N-ss) over the temperature range of 300-400 K. The C-V and G/w-V characteristics confirm that the N-ss and R-s of the diode are important parameters that strongly influence the electric parameters in MOS device. It is found that in the presence of series resistance, the forward bias C-V plots exhibits a peak, and its position shifts towards lower voltages with increasing temperature. The density of N-ss, depending on the temperature, was determined from the (C-V) and (G/w-V) data using the Hill-Coleman Method. Also, the temperature dependence of dielectric properties at different fixed frequencies over the temperature range of 300-400 K was investigated. In addition, the electric modulus formalisms were employed to understand the relaxation mechanism of the Al/HfO2/p-Si structure. (C) 2013 Elsevier B. V. All rights reserved.