The chemical and morphological properties of boron-carbon alloys grown by plasma-enhanced chemical vapour deposition

The stoichiometry and morphology of boron–carbon alloy thin films grown by plasma-enhanced chemical vapour deposition can be significantly modified by varying the deposition rate. Films grown at a rate of 5.5 nm min−1 are characterized by an amorphous-like matrix with carbon-rich and dome-like inclusions. Films grown at a deposition rate of 33 nm min−1 are found to be much more homogeneous and free of carbon-rich and dome-like inclusions. An excitation at 191.7 eV in the B 1s absorption spectrum has been associated with amorphous growth. The relative intensities of the π* and σ* excitations across the C 1s absorption edge of these boron-carbon alloys indicate that carbon bonding is predominantly through sp3 hybridization, while boron bonding is a mix of sp2 and sp3 hybridization.