Depth profiles obtained under Cs bombardment of samples of crystalline lithium niobate (LiNbO3) covered with a thin layer of metal display some artifacts related to metal/LiNbO3 interface effects. The altered yields of Li and Nb secondary ions in the first 50 nm after erosion of the metal layer can be interpreted in terms of different stopping powers between metal and LiNbO3. In this study, two typical samples are investigated and the artifacts are qualitatively explained by comparing experimental profiles and simulations performed with the transport of ions in matter code. The similarity between experiment and simulation suggests that the ballistic interpretation of the artifacts is appropriate. Copyright © 2012 John Wiley & Sons, Ltd.