beta-FeSi2 crystals have been grown on Si(I 11) substrates, and morphological modification of the beta-FeSi2/Si(111) by high temperature growth and post-thermal annealing was investigated. The morphological feature of the beta-FeSi2 crystals significantly depends on the growth conditions, especially, substrate temperature during growth. The beta-FeSi2 continuous layers with relatively smooth surfaces were grown at the low substrate temperatures of 650-700 degreesC with exposure of the grown layers to Sb flux during the growth. On the other hand, nano-scaled islands have been grown at the higher substrate temperature of 850 degreesC. The structural property, interfacial morphology and growth evolution of the beta-FeSi2 islands were examined, and compared with those for the layers grown at a lower substrate temperature. In addition, the morphological evolution of the 1 beta-FeSi2/Si layers by post-thermal annealing was examined, and it was found that the interfacial smoothness between the beta-FeSi2 layers and the Si(I 11) substrates was improved by the post-thermal annealing on condition that a thin SiOx amorphous overlayer should be formed on the beta-FeSi2 layer during the post-thermal annealing. The mechanisms of the morphological modification at the beta-FeSi2/Si(I 11) interface by the post-thermal annealing will also be discussed. (C) 2004 Elsevier B.V. All rights reserved.