Texture evolution in rhombohedral boron carbide films grown on 4H-SiC(0001̄) and 4H-SiC(0001) substrates by chemical vapor deposition.

Boron carbide in its rhombohedral form (r-B x C), commonly denoted B 4 C or B 13 C 2 , is a well-known hard material, but it is also a potential semiconductor material. We deposited r-B x C by chemical vapor deposition between 1100 °C and 1500 °C from triethylboron in H 2 on 4H-SiC(0001) and 4H-SiC(0001̄). We show, using ToF-ERDA, that pure B 4 C was grown at 1300 °C, furthermore, using XRD that graphite forms above 1400 °C. The films deposited above 1300 °C on 4H-SiC(0001̄) were found to be epitaxial, with the epitaxial relationships B 4 C(0001)[101̄0]‖4H-SiC(0001̄)[101̄0] obtained from pole figure measurements. In contrast, the films deposited on 4H-SiC(0001) were polycrystalline. We suggest that the difference in growth mode is explained by the difference in the ability of the different surfaces of 4H-SiC to act as carbon sources in the initial stages of the film growth.