Differentiation of diamond surface damage affecting heteroepitaxial growth of cBN on diamond film by shift of XPS C 1s peak

초록

The effect of ion-induced damage on diamond surface was investigated during the deposition of a heteroepitaxial cubic boron nitride (cBN) film on a diamond substrate. A microcrystalline diamond thin film deposited on a single crystal Si wafer through hot-filament chemical vapor deposition was utilized as the substrate. Boron nitride (BN) films were deposited via unbalanced magnetron sputtering using a B4C target. The damage level of the diamond surface during BN deposition was analyzed based on changes in the C1 s spectrum via X-ray photoelectron spectroscopy (XPS) measurements. Additionally, the cBN fraction in the early stages of BN deposition was estimated from XPS and Fourier-transform infrared spectroscopy results. Results showed that increasing the exposure time of ion bombardment progressively disrupted the bonding between surface diamond atoms, thus resulting in severe bonding loss at the surface atomic level and the formation of independent phases. The deposition conditions that maintain the coherence between cBN and diamond are achievable within the lowenergy range required for the formation of the cBN phase. These conditions can be determined based on variations in the XPS C1 s peak. Results of transmission electron microscopy show that the cBN film exhibited a partially epitaxial relationship with the diamond substrate.

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