Epitaxial growth of HfB2(0 0 0 1) on Si(0 0 1) by etching through a SiO2 layer

Using the single-source chemical vapor deposition (CVD) precursor Hf(BH4)4, HfB2 films can be grown epitaxially on Si substrates at 1000 °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)∥Si(0 0 1) and the X-ray rocking curve is exceptionally sharp, with full-width at half-maximum (FWHM)=0.076°. 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° from each other, HfB2[2 1 1 0]∥Si[1 0 0] and HfB2[2 1 1 0]∥Si[1 1 0].