Langmuir Characteristics of Glow Discharge Plasma in DC Reactive Magnetron Sputtering System

Abstract

In this work, the Langmuir characteristics of dc glow discharge plasma employing dual-magnetron assembly were studied. The plasma was generated by electric discharge of argon gas at pressures ranging from 0.1 to 0.8 mbar. Also, a mixture of argon and oxygen was used to generate plasma since oxygen is used as the reactive gas. First, the Paschen’s curves for both cases (argon only and argon/oxygen mixture) were plotted. The minima were also determined for the glow discharge of oxygen only to be ranging in 185-320V. In case of argon/oxygen mixture, the minima were ranging in 100-208V. The plasma parameters, mainly electron and ion temperatures and densities, were determined from the Langmuir probe measurements for argon only and argon/oxygen mixture. Electron and ion temperatures in argon/oxygen mixture were higher than those in only argon. The densities showed contradictive behaviors as the electron density was lower in argon/oxygen mixture, while the ion density was higher in the same mixture.