RF放電測定におけるシングルプローブのRF電位補償法

抄録

The circuit for compensating r. f. potential disturbance essentially consists of a capacitive probe and a feedback loop of its signal to the probe circuit has been developed. Output from the capacitive probe was fed through a phase shifter and an amplifier. The phase and the amplitude of the signal were adjusted until the probe characteristic curve is shifted toward the most positive voltage side. This was done by sweeping the probe current at a fixed d. c. probe voltage superimposed by r. f. voltage and by finding the phase and the amplitude to give the minimum current. We have analyzed the spectrum components of the plasma potential detected by the capacitive probe, which include up to 5th harmonics. Features of the present research are to expand the frequency band of the phase-shifter and the amplifier to 40MHz equivalent to the frequency of 3rd harmonics and to apply the compensation processes at every probe bias instead of compensating only at the floating potential.