Langmuir probe characteristics in RF glow discharges

The current-voltage characteristics of Langmuir probes in rf glow discharges can be misinterpreted by the effects of rf time averaging, ionization near a probe, and expansion of the probe sheath. This paper presents a new Langmuir probe technique which can be used to determine the plasma parameters in rf glow discharges. Simple expressions for the time averaged I-V characteristics are derived for the cases of fully sinusoidal and partially rectified plasma potential waveforms. Examples of corresponding I-V characteristics obtained from argon rf glow discharges are also illustrated.