Chemical vapor deposition of B12As2 thin films on 6H-SiC

Icosahedral boron arsenide (B12As2) thin films were deposited on 6H-SiC substrates by chemical vapor deposition using B2H6 and AsH3 sources. X-ray diffraction analysis of the thin films showed them to have the rhombohedral crystal structure and lattice parameters of B12As2. Transmission electron microscopy showed that the films were polycrystalline with oriented crystal grains. The preferential orientation of the film with respect to the SiC substrate was determined to be: [0001]B12As2//[0001](6H-SiC) and [10(1) over bar0](6H-SiC) to within 3 degrees. Electron diffraction also revealed the extremely small lattice mismatch (<0.5%) between the B12As2 basal-plane lattice parameter and twice the SiC basal-plane lattice parameter.