The effects of a negative bias on the nucleation of oriented diamond on Si

Abstract

Abstract The highly oriented diamond film was deposited on Si(001) substrate using the bias enhanced nucleation (BEN) proceeded at −250 V for 10 min in 3%CH4/H2 plasma at substrate temperature 750°C. The {111} X-ray pole figure of the oriented diamond film with a thickness of ca 5 μm is clearly dominated by the four {111} peaks of diamond. The full width at half maximum of the peaks in azimuth rotation and tilt are below 9 and 10°, respectively. Negative bias effects on heteroepitaxial nucleation of diamond have been investigated. It is found that the heteroepitaxial SiC was formed on the Si substrate and the high dose (ca 4 × 1016per cm2s−1) of positive ions bombarded the substrate during the bias treatment. In previous work, it was also found that the concentrations of activated atomic hydrogen and carbonaceous radical in the dense plasma were increased by negative bias. From the results, we try to combine the information based on surface and bulk analytical data and that based on the plasma analysis during the BEN process in order to explain the oriented nucleation of diamond on the Si substrate. It is suggested that the heteroepitaxial diamond can be obtained by the combination of forming heteroepitaxial SiC on the Si substrate, selective etching of Si in the SiC network, filling the vacant Si sites by carbonaceous ions, adding hydrocarbon radicals to the oriented sp3 bond carbon clusters and etching non-diamond carbon components and misoriented sp3 bond carbon clusters during the BEN process.