Initial growth of heteroepitaxial diamond on si(001) substrates via β-sic buffer layer

Negative substrate-bias effects on diamond heteroepitaxial nucleation have been investigated using microwave plasma-assisted chemical vapor deposition. The density and the percentage of azimuthally ordered particles grown on carburized Si(001) or on high-quality β-SiC(001) have been estimated by varying the bias-treatment conditions (reaction pressure, microwave power and bias voltage). The percentage of azimuthally ordered particles increases under the following conditions: pressure of 50 Torr, substrate temperature of ~900°C and bias voltage of — 50 V. Smooth heteroepitaxial diamond films of ~4µт thickness have been successfully synthesized on high-quality β-SiC(001) by the bias treatment under the above conditions followed by a two-step growth process: <001) fast growth and <111> fast growth. The initial growth of these films has been governed by the Volmer-Weber mode, where [110]- or [110]-directed protrusions have been formed on β-SiC(001). Diamond islands grew along the grooves between the β-SiC protrusions in the initial stage.