Using the single-source chemical vapor deposition (CVD) precursor Hf(BH4)(4), HfB2 films can be grown epitaxially on Si substrates at 1000 degrees C by etching through a pre-existing SiO2 layer. Despite the different symmetries in the plane of the interface, the film is oriented with HfB2 (0 0 0 1)parallel to Si(0 0 1) and the X-ray rocking curve is exceptionally sharp, with full-width at half-maximum (FWHM) = 0.076 degrees. Top-view scanning electron microscope (SEM) micrographs show that the film consists of micrometer size domains on the substrate. X-ray pole figures and electron backscattering diffraction studies indicate the existence of four types of domains with in-plane orientations rotated 45 degrees from each other, HfB2[2 (1) under bar(1) under bar 0]1=parallel to Si[100] and HfB2[2 (1) under bar(1) under bar 0]parallel to Si[110]. (C) 2008 Elsevier B.V. All rights reserved.