The properties of perovskite (i.e., SrTiO3) precious-metal interfaces and particular causes of leakage currents are well studied in microelectronics capacitor applications. The Schottky emission model based on oxygen vacancies is a promising theory; however, in technically interesting cases, vacancy density is too small to describe a continuous band diagram. There is a need to explain why the model seems promising while its assumption of the band diagram is not justified. Thus, we calculated a leakage current induced by a single oxygen vacancy and found that linear approximation is applicable; the linearity justifying the use of the Schottky emission model results. (c) 2006 Elsevier B.V. All rights reserved.