Abstract
Self-bias potential and its distribution of a radio-frequency (RF) electrode have been measured in argon and helium plasma using probes penetrating the electrode. In the absence of the magnetic field the self-bias potential distribution is almost homogeneous at-150 V (RF power = 26 W) in Ar plasma. When the magnetic field (B =0.04 T) parallel to the electrode is applied, the mean value of the potential is reduced to-40 V and the gradient in the potential distribution occurs along the E× B direction. Rotation of the magnetic field at a frequency below 50 Hz is unable to reduce potential inhomogeneity, but this technique enables us to measure the potential distribution as a continuous function of the azimuthal angle. In helium plasma, another type of inhomogeneity parallel to the magnetic field occurs; this inhomogeneity can be reduced effectively by pulsed Ar gas injection. These data are discussed to show physical meaning and industrial applications.
