Modification of the ratio between $sp^2/sp^3$-hybridized carbon components in PECVD diamond-like films

It is known that diamond-like carbon layers consist of carbon components with $sp^2$ (graphite) and $sp^3$ (diamond) hybridizations of electron orbitals. The quantitative ratio between $sp^2$ and $sp^3$ 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 $sp^2$- and $sp^3$-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 $sp^3$ 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.