As described in detail in our previous paper, r-B4C thin films were deposited on the Si-face and C-face of 4H-SiC substrates in a hot-wall horizontal CVD reactor in the same CVD experiment. The single source CVD precursor triethylborane (TEB, B(CH2CH3)3, 99.99 %, SAFC HiTech) was fed to the reactor zone from a stainless-steel bubbler immersed in a water bath at 0 °C allowing control of the vapor pressure at ~1.65 kPa. The CVD gas mixture was 0.7 SCCM TEB, enabled by bubbling 20.8 SCCM through the bubbler which was kept at 600 mbar and 0 °C, in 5000 SCCM dihydrogen gas (H2, Palladium membrane purified). The dihydrogen acted as a carrier gas for the TEB from the bubbler and as a dilution gas in the CVD process.