Ion current to a substrate in the pulsed dc hollow cathode plasma jet deposition system

P Virostko (1) , Z Hubika (1) , M Čada (1) , M Tich (2)

1 Institute of Physics
2 Faculty of Mathematics and Physics [Praha/Prague]

The current of positive ions to a substrate was studied in the pulsed DC hollow cathode plasma jet system for deposition of thin films working at low pressures. Time evolution of electric current to a planar probe with pulsed negative DC bias was measured. The pulsing of the bias of the probe was applied to allow measurements with a dielectric film being deposited on its surface. The frequency of pulsing of the probe bias was higher than the frequency of pulsing of the discharge. Time evolution of the ion current density to the probe j i was determined for the whole period of modulation of the discharge for the discharge repetition frequency 2.5 kHz and different duty cycles D. The mean ion current density j i, averaged over the whole period of the discharge, was rising with the decreasing D although the value of the mean discharge current was kept constant. A simple theoretical model is proposed to explain this effect. It is shown that the observed rise of j i with decreasing D is in major part caused by the rise of the ion current in the afterglow region of the pulsed discharge.

Mots clés: Physical Sciences

P Virostko, Z Hubika, M Čada, M Tich. Ion current to a substrate in the pulsed dc hollow cathode plasma jet deposition system. Journal of Physics D: Applied Physics, 2010, 43 (12), pp.124019. ⟨10.1088/0022-3727/43/12/124019⟩. ⟨hal-00569564⟩