Investigation of the E–H mode transition in pulsed inductively coupled argon plasmas by two-dimensional hybrid simulation

Abstract In pulsed inductively coupled plasmas, since the power switches on and off every pulse cycle, the discharge experiences frequent mode transition. In this work, a two-dimensional fluid/electron Monte Carlo hybrid model is employed to gain further insight into the physical mechanism behind the mode transition in pulsed Ar discharges. The results show that the mode transition behavior varies significantly with position, which is caused by the non-uniform electric field and thus the inhomogeneous inductive and capacitive power deposition profiles. For instance, the discharge below the coils transits to the H-mode earlier than other positions at the same height, while at the radial center and above the substrate, it remains in the E-mode even at the 500th radio-frequency cycle. Furthermore, the spatiotemporal distribution of the ionization rate gradually evolves from one peak to two equal peaks as pulse progresses. The electron energy probability function also depends on the position, i.e. it changes from a Maxwellian distribution to a Druyvesteyn distribution at r = 6 cm below the dielectric window, and it transits from a bi-Maxwellian distribution to a three-temperature structure at the axial middle-height.