In this paper we report the detailed analysis of the effect of in-situ annealing on the electrical properties of yttrium stabilized zirconium oxide (YSZ) thin films grown by pulsed laser deposition on silicon substrates. The optimized metal/YSZ/Si devices showed low leakage current, good dielectric strength and a breakdown field strength of 4.13 MV/cm. The magnitudes of flat band voltage, and interfacial charge density have been extracted from the capacitance-voltage (C-V) characteristics of the MOS structure. The C-V characteristics show a small hysteresis which indicates the presence of traps. The observed shift in the flat band voltage and hysteresis are explained with the help of X-ray photoelectron spectroscopy. From the XPS depth profile analysis of the samples it was found that as we go from the surface to the interface, oxygen concentration in the deposited film decreases, i.e. the oxide becomes zirconium rich. This has been correlated with the observed electrical properties. © 2020 Elsevier B.V.