Cubic InN (zincblende structure) films have been successfully grown on yttria stabilized zirconia (YSZ) (0 0 1) substrates by RF-plasma-assisted molecular beam epitaxy. The X-ray diffraction analysis has confirmed the growth of cubic InN films whose growth temperature was 400-490 degrees C and crystal quality is higher than that on GaAs (0 0 1) substrate. The structural properties (i.e. crystal quality and cubic phase purity) of the InN films are obviously improved for the growth condition of a slightly In-rich side of the surface-stoichiometry. By 2 theta/omega and omega X-ray reciprocal space mapping measurements, hexagonal phase InN (h-InN) is found to be generated from c-InN{111} facets. By annealing at several temperatures in air, the surface morphology of YSZ substrates remarkably changes and appears as the stepped and terraced structure. With increasing annealing temperature, the step wandering disappears and the step edges become straighter. By using YSZ substrate with stepped and terraced structure for cubic InN growth, the volume content of cubic InN is drastically increased and is estimated to be similar to 95% at maximum based on an analysis of the X-ray diffraction intensity. (c) 2006 Elsevier B.V. All rights reserved.