Plasma diagnostics in the pulse magnetron sputtering system used for deposition Ti-C:H thin films

DC pulse magnetron sputtering system has been characterized by means of time resolved emission spectroscopy and Langmuir probe measurement in dependence on the pulse power. Measurements have been done at conditions used at sputtering of titanium target in the gas mixture of Ar and CH4. As the Langmuir probe measurement was synchronized with modulation pulses, the plasma evolution during the active pulse and plasma decay during nonactive part of the duty cycle was observed. Time-resolved emission spectroscopy measurement was done in the vicinity of the target. Ar, Ti, and CH species were detected by emission spectroscopy. Relative ratios of these lines were investigated in dependence on both pulsed and continuous discharge power. In contrast to continuous sputtering, emission of Ar and CH lines for the pulse power was almost proportional to instant pulse power and considerably higher than that for the same continuous power.It was found that the electron temperature and concentration in the active part of the duty cycle was approximately constant. Electron distribution function was found to be non-Maxwellian in the active part of modulation period with the mean electron energy E≈11 eV. However, two groups of electrons were found in the decaying part of the duty cycle. The fast electrons with approximately Maxwellian distribution have the mean energy Eh≈10 eV and the cold ones have Ec≈1 eV.