Regensburg 2004 – wissenschaftliches Programm
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DS: Dünne Schichten
DS 1: Ionenimplantation I
DS 1.9: Vortrag
Montag, 8. März 2004, 11:30–11:45, HS 31
Conditions resulting in an epitaxial growth of cubic boron nitride films on diamond substrates by ion beam assisted deposition — •X.W. Zhang, H. Yin, R. Lang, H.-G. Boyen, and P. Ziemann — Abteilung Festkörperphysik, Universität Ulm, D-89069 Ulm
Cubic boron nitride (c-BN) films were grown on highly (100)-oriented chemical vapour deposited diamond films at various substrate temperatures (TS) ranging from 420∘C to 1000∘C by using Ion Beam Assisted Deposition (IBAD). The resulting c-BN films were characterized by Fourier transformed infrared spectroscopy, high-resolution transmission electron microscopy, Rutherford backscattering spectroscopy as well as X-ray diffraction. The results demonstrate that the epitaxial growth of c-BN films on diamond can be realized only at high values of TS ( 900∘C), while at e.g. 420∘C, an intermediate hexagonal BN layer is formed between the substrate and the c-BN film as it is usually observed for c-BN growth on top of Si. This may be due to the amorphization or graphitization of the diamond surface at low TS due to the assisting ion bombardment during c-BN nucleation. The plasmon energies of the diamond substrates that were held at various temperatures and bombarded by a mixture of argon and nitrogen ions were determined from in situ low-energy electron energy loss spectra. The results indicate that at higher TS values radiation damage can be annealed out thereby maintaining an sp3-dominated substrate surface, hence allowing epitaxial growth of c-BN. Furthermore, a 500 nm thick c-BN film was deposited on a (001) single crystal diamond substrate under optimum conditions. The rocking angles of 0.2∘C) as observed by x-ray diffraction, point to a strongly improved alignment.