DIRECT ELECTRICAL CONTROL OF DIAMOND-LIKE CARBON GROWTH BY PLASMA-ENHANCED CVD

Control of the plasma density, electron temperature and space potentia l over almost one order of magnitude has been achieved for an r.f. dis charge by the addition and removal of electrons. A thermionic filament provided the electron source and a d.c. anode was used as an electron sink. The energy of ion bombardment of earthed surfaces has been redu ced to substantially less than 10 eV, and film growth under these cond itions has been studied. The power input to the discharge associated w ith the electron source and sink were only a small fraction of that fr om the main r.f. source. The Raman spectra of diamond-like carbon samp les prepared in an argon-methane-hydrogen plasma indicate that on Ti t he filament assistance decreases the degree of disorder whereas on sil icon the effect is to increase disorder.