Thin films of Y1Ba2Cu3Ox,ZrO2, and yttria-stabilized zirconia (YSZ) have been deposited on Si(100) by the UV-laser ablation technique, and characterized by several techniques including x-ray photoemission spectroscopy (XPS) and cross-sectional transmission electron microscopy (XTEM). Si substrates were prepared by several techniques including thermal oxidation, and oxide etching and passivation by hydrogen termination. Certain of these YBCO films (= 250 nm thick) deposited on YSZ buffer layers have excellent superconducting properties. Other YBCO and zirconia films, deposited to 2-5 nm thickness and transferred under dry N2 into UHV, allowed XPS evaluation of the thermal and chemical stability of the interfaces and nearby regions. 2-nm films of YBCO on 15-nm films of SiO2/Si, deposited at 550–670 °C, showed Cu 2p core-level XPS lines similar to those of bulk YBCO (i.e., Cu II) but with two components due to reactions. The Si 2p line showed formation of silica on the YBCO surface at 670 °C and of silicate at 550 °C. XTEM lattice images showed that use of H-terminated Si produced superior interfaces with the zirconia films.