High-quality all-oxide thin film metal-semiconductor junctions, fabricated of a half-metallic ferromagnet La0.7SrO3MnO3 and of a niobium doped n-type semiconductor SrTiO3 (SrTi0.8Nb0.2O3) by pulsed laser deposition, were studied in terms of their electronic transport properties in a wide temperature range. A fabrication process for ultrathin film metal-semiconductor junctions with micrometre-sized mesas has been established. The current -voltage characteristics of the junctions were found at variance with the conventional thermionic emission theory often applied to explain the transport properties of Schottky contacts. This, discrepancy is tentatively ascribed to the very high electric field in the ultrathin SrTi0.8Nb0.2O3 layer and its effect on carrier depletion and dielectric constant. (C) 2016 Elsevier B.V. All rights reserved.