Epitaxical nucleation of polycrystalline silicon carbide during chemical vapor deposition

Polycrystalline silicon carbide was deposited from methyltrichlorosilane in cold-walled and hot-walled reactors, on (100) SiC surface layers that were formed on (100) Si wafers. The initial stages of the process were studied by electron microscopy after relatively short deposition times. Submicron surface features nucleated with a specific crystallographic orientation with respect to the substrate, where {111} planes in the β-SiC substrate coincided with {0001} planes in the α-SiC features. These α-SiC features occurred only at twins on {111} planes of the β-SiC substrate. This demonstrates that nucleation under these conditions is controlled by defects in the substrate. Surface contamination and the reactor configuration also had substantial effects on nucleation.