In comparison to structurally similar materials such as rhombohedral boron subphosphide (B12P2) and subarsenide (B12As2), the threshold temperature for epitaxial growth for r-BxC is comparable to the one reported for the CVD of B12P2 and similar structural variants such as twinning was observed in B12As2 and B12P2 epitaxy, albeit on on-axis Si-face 4H-SiC(0001). A notable difference is observed in the evolution of crystalline quality with temperatures as seen from rocking curves measurements: the crystalline quality of B12P2 and B12As2 was reported to degrade from 1350°C and 1450 °C19 , respectively, while the crystalline quality of r-BxC continues improving even up to 1500 °C. This could be attributed to the formation of volatile P or PHx (respectively As or AsHx) species from the deposited film, which is less prone to occur in the case of carbon, albeit at the cost of forming graphite. Finally, the presence of two components in our rocking curves measurements further suggests that the crystallites of the epitaxial r-B4C films initially grow well aligned with the substrate at the early stages of the growth and deviate slightly later on, as in Ref .