Auger electron spectroscopy using excitation via grazing impact of protons was applied to determine the elemental composition of the topmost and near-surface layers of a NdGaO3(1 1 0) substrate. The preparation conditions of vicinal NdGaO3 substrates were optimized by varying the annealing temperature, time, and gas atmosphere. Well prepared surfaces show regularly arranged, atomically smooth terraces with single-atomic steps. The surfaces were always NdO terminated with a small amount of Ga (2-4%) atoms on the surface. A Ga and O depletion layer with a thickness of about 4 nm has been detected at optimized preparation conditions. (C) 2009 Elsevier B. V. All rights reserved.