A TEM study has been carried out to clarify the structural property of beta-FeSi2(1 1 0),(1 0 1)/Si(2 1 1) layers grown by reactive deposition epitaxy (RDE) in the presence of an Sb flux. It is found that the layer is continuous and relatively smooth, and domains in the layer are distributed below and above the original substrate surface. The formation of internal planar defects due to 90degrees-related order domains is partly suppressed, and equiaxed domains without the planar defects are formed in the beta-FeSi2 layer. The result is compared with that of the layer grown by conventional RDE, and the improvement of the structural property is confirmed for the Sb-mediated RIDE grown layer. (C) 2002 Elsevier Science B.V. All rights reserved.