Study on the Discharge Characteristics of Low-Pressure Magnetized Capacitively Coupled Ar/CH 4 Plasma

The effect of an inhomogeneous transverse magnetic field on the discharge characteristics of a dual-frequency (13.56/27.12 MHz) capacitively coupled plasma (DF-CCP) is investigated using a 1-D particle-in-cell/Monte Carlo collision (PIC/MCC) simulation. The discharge gas pressure is 5 mTorr. Both the low-frequency (LF) power and high-frequency power are 60W, and the electrode spacing is 3.2 cm. The magnetic field changes from 30 to 80 G. The results indicate that the electron density exhibits pronounced asymmetry when the magnetic field is above 50 G. With increasing magnetic field, both the electron current density and electron heating rate rise, while the electron temperature increases and reaches a maximum when the magnetic field is 70 G. The mean free path indicates that kinetic disparities between low- and high-energy electrons are big at higher magnetic field, which drive discharge asymmetry. At 80 G, this kinetic disparity is reduced, and all electron populations are localized, so the symmetry is recovered. The electron energy probability distribution function (EEPF) changes from a bi-Maxwellian-like distribution to a single Maxwellian-like distribution with increasing magnetic field. The incidence angles of CH ${}_{4}^{+}$ and CH ${}_{3}^{+}$ ions on the electrodes also change markedly with the change of the magnetic field. The electron and ion fluxes of CH ${}_{4}^{+}$ and CH ${}_{3}^{+}$ demonstrate that the magnetic field-induced asymmetry results in higher fluxes on one side and lower fluxes on the opposite side at higher magnetic field (60–80G). The magnetic field has a significant influence on the discharge characteristics of Ar/CH₄ CCPs, which can be utilized for tuning the kinetic behavior of plasma species.