In order to bring single crystalline oxide thin films towards commercial applications, epitaxial integration on silicon wafers is required. Epitaxial integration of oxides on silicon is a challenging task, mainly because of the chemical interactions between silicon, oxygen and metal oxides. Most of the metal oxides react with silicon to form silicide and/or silicate phases1,2, which prevents epitaxial crystallization of the growing oxide and can deteriorate the functional properties of the film. Besides, an amorphous native oxide always forms on silicon, preventing growth of the oxide directly on the silicon crystal lattice. This native oxide can be removed prior to growth, but ultra high vacuum conditions are required to keep the very reactive bare silicon surface free from carbide and oxide formation3,4. Those conditions are hard to reach in growth systems, and low oxygen pressures are contrary to the necessity to supply sufficient oxygen to the growing oxide film5. In order to avoid these issues, yttria-stabilized zirconia (YSZ) can be used as a buffer layer to incorporate epitaxial oxides on Si. During growth in reducing conditions, the deposited YSZ decomposes the native oxide through redox reactions, after which a chemically stable film crystallizes epitaxially on the Si crystal lattice6. In this way, formation of unstable surfaces is avoided, and therefore the need to work in ultra high vacuum conditions. Very smooth surfaces can be obtained by a variety of Physical Vapor Deposition techniques, e.g. Pulsed Laser Deposition (PLD)7–9, radio-frequency magnetron sputtering10 and electron-beam evaporation6,11. The highest quality films have a full width at half maximum (FWHM) of the X-ray Diffraction (002) rocking curve of around 0.7°. Normally, an additional epitaxial fluorite CeO2 layer is grown on the YSZ film to obtain a suitable template for growth of a perovskite oxide12. Growth of epitaxial (001) oriented perovskites with good functional properties on top of these buffer layers is well established13–16. However, the growth mechanism of YSZ on Si by e.g. PLD is not known in detail, which is important to obtain reproducible growth and information about important growth parameters when upscaling growth to large silicon wafers.