The PSR effect of matching network in 8/100 MHz geometrically symmetrical capacitively coupled Ar plasma

Abstract

The high-order harmonics caused by the self-excitation of nonlinear plasma series resonance (PSR) in a geometrically symmetric (8 + 100) MHz capacitively coupled argon plasma are studied by using a nonlinear global model. The voltage waveforms and current waveforms measured by oscilloscope between the two electrodes are used to observe the harmonics. The voltage waveforms are used as input parameters for the nonlinear global model to simulate harmonics of the sheath charges of low-frequency electrode, bias voltage, and plasma RF current. These discharged parameters considering coupling effect between these two frequencies and without considering coupling effect are compared in (8 + 100) MHz capacitively coupled plasma with the increasing low-frequency powers at a pressure of 30 mTorr. These results indicate that the theoretical discharge behavior without considering the coupling effect has big difference from the real experiment. The PSR effect of the matching network plays an important role in modulating the plasma homogeneity. Therefore, how to design a suitable matching network to enhance the PSR effect is more meaningful for the nonlinear dynamics of plasma.