In this study, frequency and voltage dependence of dielectric constant (epsilon'), dielectric loss (epsilon aEuro(3)), loss tangent (tan delta), the real and imaginary parts of electric modulus (M' and MaEuro(3)) and ac electrical conductivity (sigma (ac)) of an Au/PVA (Bi-doped)/n-Si Schottky barrier diode have been investigated in detail by using experimental C-V and G-V measurements in the wide frequency range of 5 kHz-10 MHz and the voltage range of +/- 2 V at room temperature. Experimental results indicate that the values of epsilon',epsilon aEuro(3), tan delta and sigma (ac) are strongly frequency and voltage dependent. It has found that the values of epsilon',epsilon aEuro(3) and tan delta decrease while the values of sigma (ac), M' and MaEuro(3) increase. It is clear that the values of MaEuro(3) show a distinctive peak with a U-shape and its position shifts towards the positive-bias region with increasing frequency. Such behavior of the peak can be attributed to the particular distribution of interface states located at the Si/PVA interface and interfacial polarization. It can be concluded that the interfacial polarization and the charge at the interface can easily follow the ac signal at low frequencies.