Diagnostics of the hexagonal boron nitride interface layer by in situ FTIR reflection spectroscopy

Growth of hexagonal boron nitride (h-BN) interface layer between TiN covered steel substrates and cubic boron nitride (c-BN) film was investigated in situ by polarised infrared reflection absorption spectroscopy. The position and form of the Berreman peak in p-polarisation depend strongly on deposition conditions. The influence of the bias voltage as well as of the BN deposition rate on the peak shift was investigated in detail. Data evaluation indicates that at higher film thickness the texture of h-BN could be changed during growth. c-BN nucleation only was achieved if h-BN Berreman absorption peak frequencies was in the range between 1565 and 1575 cm−1. At this condition stable c-BN films in the thickness range of 1.6 μm were obtained.