Modification of the Ratio between sp2- to sp3-Hybridized Carbon Components in PECVD Diamond-Like Films

It is known that diamond-like carbon layers consist of carbon components with sp2 (graphite) and sp3 (diamond) hybridizations of electron orbitals. The quantitative ratio between sp2 and sp3 components has a profound effect on the structural, morphological, optical, electrical, and mechanical properties of the films. In this study, the possibility of controlling the fractions of sp2- and sp3-hybridized carbon in diamond-like films produced by plasma-enhanced chemical-vapor deposition onto single-crystal silicon and diamond substrates is analyzed. In-situ methods of controlling the fraction of the sp3 component by varying the power of the capacitive and inductively coupled discharges directly during production of the film and ex-situ methods, in which use is made of thermal annealing and the application of an electric field, are demonstrated.