Initial Growth of Heteroepitaxial Diamond on Si(001) Substrates via β-SiC Buffer Layer

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Abstract
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 ∼4 µ m 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: fast growth and fast growth. The initial growth of these films has been governed by the Volmer-Weber mode, where [1̄10]- 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.