As homo-epitaxial growth of SnO2 in Cu2O flux progresses, steps on (I 10) are bunched regardless of whether Cr ions exist as impurities in the system. We have confirmed by AFM observation that the bunching step is made up of a few elemental steps, and that these elemental steps maintain separation between themselves of tens of nanometers in a pure system. In the case of a Cr-added system, however, the elemental steps that make up the bunching step also maintain step separation, but the interval between each elemental step is only a few nanometers. These results suggest that the Schwoebel effect functions in high-temperature solution systems. These morphologies could not have been observed by a differential interference microscope (DIM) because the horizontal resolution of the DIM is limited. Furthermore, the as-grown surface of a single crystal of SnO2 could be observed due to the low wettability of the Cu2O flux on the SnO2 surface. (C) 2002 Elsevier Science B.V. All rights reserved.