X-RAY SPECTROSCOPIC ANALYSIS OF BORON-NITRIDE CLUSTERS DEPOSITED BY ION-PLATING METHOD

Cubic boron-nitride (c-BN) films were deposited on a silicon substrate by varying the deposition time, using a reactive ion-plating method. In order to investigate the growth mechanism of c-BN films, these c-BN films were characterized by x-ray emission spectra of boron (B K x-ra y emission spectra), infrared absorption spectra, selected area diffra ction patterns, and TEM microstructures. It was found that the BN film with sp(2) bonding formed initially on the substrate and subsequently c-BN film formed. The c-BN film was composed of fine crystallites wit h a size of about 10 nm and with random orientation. In the case of th e B K x-ray emission spectrum from the BN film with sp(2) bonding, the intensity of the satellite peak at the short-wavelength side was extr emely stronger than that of sp(2)-bonded BN-like turbostratic or hexag onal BN. As a result of calculation of the B K x-ray emission spectrum of BN using the discrete variational Hartree-Fock-Slater (DV-X alpha) method, it was found that the satellite peak intensity increased with formation of the fine BN cluster having two-coordinated boron (which has a dangling bond) and with decreasing size of the cluster. Therefor e, it is considered that the BN film with sp(2) bonding was composed o f the very fine BN cluster having two-coordinated borons, and became t he precursor of c-BN film at the interface between the substrate and c -BN film.