The surface states (N-ss), relaxation time (tau), and series resistance (R-s) values as a function of frequency for various bias voltage of the metal-insulator-semiconductor (MIS) structure were obtained by using the impedance measurements which is including capacitance (C) and conductance (G/omega) in the frequency range of 0.5-500 kHz at room temperature. C/G-V plots for each frequency have inversion-depletion-accumulation regions and show a strong frequency and voltage-dependent at low-moderate frequencies due to the existence of N-ss, R-s and Zinc Oxide (ZnO) interlayer. The parallel conductance (G(p)/omega) between -2 and 1.5 V shows a distinctive peak for almost every voltage and its position shifts to higher frequencies with increasing voltage. The values barrier height (Phi(B)), concentration of donor atoms (N-D), and depletion layer thickness (W D ) were calculated from the slope and intercept C-2-V plots as function of frequency. On the other hand, ideality factor (n), barrier-height (Phi(Bo)) and R-s of the structure were calculated from both the thermionic-emission (TE) and Cheung functions which are usually good consisted with each other, some little discrepancies in them were attributed to the voltage-dependent of them and the nature of the used technique.