Diamond deposition with ArCO2CH4H2 plasma jets

Abstract Diamond deposition on an Mo substrate was attempted using Ar0.1vol.%CO 2 H 2 , Ar0.1vol.%CO 2 0.1vol.%CH 4 and Ar0.1vol.%CO 2 0.1vol.%CH 4 H 2 plasma jets at a pressure of 26 kPa. No diamond was observed with deposits from the ArCO 2 H 2 and ArCO 2 CH 4 plasma jets. By the addition of limited amounts of H 2 into the ArCO 2 CH 4 plasma jet, diamond was observed in the deposits by means of scanning electron microscopy observation, X-ray diffraction and Raman spectroscopy. The limited amounts of hydrogen adjust the C-to-H-to-O ratio in the CHO system. The nucleation and growth rates of diamond crystals during deposition were considerably lower than those from the ArCH 4 H 2 or ArCOH 2 plasma jet. As the CH and CO radicals were identified in the emission spectra from the plasma jets, these species would contribute to the deposition of diamond. However, O atoms included in the plasma jet may etch the deposit.