The effects of match circuit on the breakdown process of capacitively coupled plasma driven by radio frequency

Abstract

The breakdown process of capacitively coupled plasma (CCP) in the presence of a matching network is rarely studied, even though it is the indispensable part of the most laboratory and industrial devices of CCP. Based on the method of Verboncoeur, the solution method of the general “L”-type match circuit coupled with a particle-in-cell/Monte Carlo code is deduced self-consistently. Based on this method, the electrical breakdown process of CCP is studied. Both the plasma parameters and the electric parameters of the matching network during the breakdown are given and analyzed. In the pre-breakdown phase, the entire circuit can be considered as a linear system. However, the formation of the sheath during breakdown significantly enhanced the capacitance of the discharge chamber, which changed the electric signal amplitude of the external circuit. With the stabilization of plasma, the equivalent capacitance of CCP increases, which continues to change the electrical signal until the steady-state is reached. Accompanied by plasma stabilization is the appearance of high-order harmonics of discharge current caused by the gradually oscillating CCP capacitance. The breakdown characteristics can be obviously affected by the capacitance of the matching network. In the case of a breakdown zone, some breakdowns with special characteristics can be obtained by choosing the different capacitors. These works might be a reference for understanding the interaction between the plasma and the external circuit during the breakdown process and how to modulate the gas breakdown by controlling the external circuit.

Application of similarity laws to dual-frequency capacitively coupled radio frequency plasmas with the electrical asymmetry effect

“…In practical applications, the impedance matching network and the stray and actual components attached to the electrode should be taken into account in dual-frequency rf plasma [64][65][66][67]. Thus, additional investigations with comprehensive matching network in the PIC simulation [68] are also highly suggested with respect to the similarity rules. It should also be noted that under industrial conditions, there could be challenges for the application of SLs, such as the utilization of various reactive gases [69][70][71], potentially existing parasitic discharges [72], collisional plasmas at higher pressures (e.g., deposition process [1,73,74]), and the plasma non-uniformity (e.g., striations [75,76] and the standing wave effect [77][78][79]) in multidimensional geometries, which should be further investigated.…”

Numerical characterization of capacitively coupled plasma driven by tailored frequency modulated radio frequency source

“…To simplify the model, the coupling with the secondary electron and external circuit model is not considered in this study. However, the matching network of RF driven CCP generally needs to be designed according to the power frequency [54,55]. The question of how to design the matching network of the CCP driven by an FM RF source remains an unsolved problem.…”

Gas breakdown in radio-frequency field within MHz range: a review of the state of the art

“…However, a single blocking capacitor can never replace the matching circuit in real discharge. Thus, based on the work of Verboncoeur [71], we studied the whole MRF breakdown process under the commonly-used L-type matching circuit [78]. The different matching devices can significantly affect breakdown and even change the direction of the evolution and breakdown curve (shown in figure 7).…”

“…The actual drive circuit has a complex matching circuit and coaxial cable (figure 2), the circuit has processes such as capacitive charging, the plasma has a significant change in impedance before and after breakdown, and the MRF voltage may be reflected on the coaxial cable, so the breakdown model must include the complete external circuit and transmission-line model. The breakdown model must include a complete external circuit model [71,72,74,78,[103][104][105]. In the case of a capacitively coupled plasma, for example, the circuit is linear before breakdown and the pole plate can be considered as a vacuum capacitor, while the plasma has both capacitive and resistive components and is nonlinear due to the presence of the plasma and sheath layer after a breakdown.…”

“…[78], as shown in figure9. It can be seen that the plasma is able to break down normally only for C 2 = 160 pF in the matched circuit; while C 2 = 100 pF the avalanche process does not occur due to the low pole plate voltage, and this failure breakdown mode, which occurs in the initial stage, can be studied with conventional Monte Carlo simulations, fluid or PIC/MC models without the external circuit; while C 2 = 150 pF and C 2 = 250 pF, the avalanche process can occur, but the breakdown does not occur because the plasma density increases and then decreases due to the load voltage change caused by the load impedance change, and this breakdown failure mode that occurs during the sheath formation process cannot be studied by previous models.…”