新手法による誘導結合型プラズマのインピーダンス測定 Impedance Measurements for Inductive Coupled Plasmas with New Technique
We developed a new measurement system for the antenna current to obtain a plasma impedance that was hardly measured due to the low inductance of the antenna coil. When a conventional measurement system was used, the phase angle between the voltage and current was 81° for a high density Ar plasma (10<SUP>11</SUP> cm<SUP>-3</SUP> plasma density at 6.7 Pa). With new cancel circuit that subtracts the current flow to the coil inductance, the current was down to ten times smaller and the phase angle decreased to 54°. Both the power dissipation and the plasma density measured by the Langmuir probe were almost direct proportional to the current. It was also demonstrated theoretically that the new system is useful for the measurement of the impedance and power dissipation in plasmas.
真空 42(3), 337-340, 1999-03
The Vacuum Society of Japan