The Effect of RF Power on the Growth of c-BN Films on Nickel Substrates

Abstract

High quality cubic boron nitride (c-BN) films have been prepared on polycrystalline Ni substrates by hot filament assisted rf plasma chemical vapor deposition (CVD). Grazing incidence X-ray diffraction (XRD) measurements, X-ray photoelectron spectroscopy (XPS), and infrared absorption spectroscopy reveal that the resulting films are composed of the c-BN phase. The well-faceted c-BN grains are viewed in scanning electron microscopy (SEM) images. Based on results of XRD measurements, we investigate the effect of rf power on the phase purity of the films and the orientation of the grains. It is found that rf power is a determining parameter in improving the growth of c-BN grains and suppressing the formation of h-BN phase. An appreciable rf power can result in a preferentially (200) and (220) oriented growth of c-BN films. The optimum power density of rf plasma is at the intermediate level of approximately 2.83 W/cm2. The momentum model of the reaction radicals is applied to discuss the effect of the rf power on the growth of c-BN films on Ni substrates.