The characteristics of sub-micron scale crystalline-crystalline interface roughness in CuInSe2 thin films have been studied using transmission electron microscopy. The interface is formed by local recrystallization of CuInSe2 films using electron beam irradiation in a transmission electron microscope. Analysis of the interface data obtained from the electron micrographs suggested that the interface shows self-affine fractal scaling with a static scaling exponent of 0.97 +/- 0.02. (C) 2002 Elsevier Science Ltd. All rights reserved.