Electron Microscopic Phase Analysis of BN-Thin Films

U. Falke, S. Schulze, M. Hietschold
Technische Universität Chemnitz, Institut für Physik
Analytik von Festkörperoberflächen
D-09107 Chemnitz
Germany

M. Röder, J. Hahn, F. Richter
Technische Universität Chemnitz-Zwickau, Institut für Physik
Technische Physik / Physik fester Körper
D-09107 Chemnitz
Germany

A series of BN films was deposited by means of r.f. magnetron sputtering of a h-BN target onto Si(100) surfaces. Hereby, the substrate bias voltage was varied. Special interest is focussed to the influence of the deposition parameters on the orientation of the growing hexagonal BN film with respect to the substrate. For structural investigation, cross section samples were prepared. In addition to HRTEM and diffraction investigations, especially the electron energy loss spectroscopy (EELS) was applied successfully for phase identification. For negative bias voltages of U_B = -300 V and U_B = -350 V, we found a phase system consisting of a first-grown 25 nm thick layer of hexagonal structure with c axis parallel to the substrate surface followed by the cubic phase.