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 Is absorption spectrum has been associated with amorphous growth. The relative intensities of the pi* and sigma* excitations across the C Is absorption edge of these boron-carbon alloys indicate that carbon bonding is predominantly through sp(3) hybridization, while boron bonding is a mix of sp(2) and sp(3) hybridization. (C) 1998 Kluwer Academic Publishers.