Diamond films were grown, under identical conditions on scratched Si (100) with and without MgO interlayers by using hot filament chemical vapour deposition. Initially both kinds of the substrates were biased for 30 min at 750 +/- 50 degrees C to enhance the nucleation density. A 1 : 100 vol.% mixture of CH4 and H-2 gases was used for deposition at a total pressure of similar to 4 x 10(3) Pa. Deposition was carried out for total of 2 h and the analysis of the films was carried out using Scanning Electron Microscopy, Atomic Force Microscopy, X-ray Diffraction and Raman Spectroscopy. Both substrates showed predominantly (I 11) oriented crystals of diamond but with different surface morphology. The crystallites on scratched Si (100) surface are in general (similar to 1.5-2 mu m) and those on MgO overlayer are smaller (< 1 mu m), but denser film occurs with MgO overlayer on Si (100) substrate. (c) 2005 Elsevier B.V. All rights reserved.