PLASMA PARAMETERS DERIVED FROM ELECTRICAL MEASUREMENTS IN RF PARALLEL PLATE ARGON GLOW DISCHARGES

The voltage and current waveforms are measured at the rf powered electrode lead feedthrough of a parallel-plate capacitively coupled rf discharge chamber. A proper cell's stray impedance characterization technique is used in order to convert the measured values to equivalent ones at the surface of the powered electrode. This has led to the accurate determination of the power that is actually consumed in the glow discharge process. The dc self bias potential of the powered electrode is used for the bulk plasma amplitude potential determination and combined with the voltage and current measurements has given the impedances of two distinct regions in the glow discharge. An equivalent electrical circuit model is used and the electrical characteristics of each of the two regions are discussed. Final, the equivalent electrical circuit model is used to relate the electrical data to the width of the powered electrode sheath.