Deposition of hard carbon coatings using combined inductively and capacitively coupled plasma sources

A combined inductively coupled plasma (ICP) and capacitively coupled plasma (CCP) source has been presented. Diamond-like carbon (DLC) films can be prepared on BK7 glass substrates using only the CCP source. An efficient cooling of the substrates is very important to obtain DLC films when the ICP source is also supplied. The refractive index n and the thickness of the DLC films on BK7 glass substrates were determined from transmission spectra by a computer program. Without CCP power the deposits on scratched Si samples at the pressures of 0.1-1 mbar in a CH4/H2/Ar gas mixture are microcrystalline or nanocrystalline diamonds. The morphology of the diamond films changes to pyramidal-like on scratched and ball-like crystals on unscratched Si samples when a CCP power is applied to use as a bias voltage source. The effect of the ratio of CCP to ICP power on the structure and morphology of diamond films has been investigated. Ball- and pyramidal-like crystals size and sp3 content increase with increasing ratio of CCP to ICP power.