Effects of amplitude modulation discharge on behavior of oxygen ions in Ar/O₂ capacitively coupled plasma studied by particle-in-cell/Monte Carlo collision model

Oxygen ions (O₂⁺, O^-) play key roles in fabrication of SiO₂ insulating films by plasma-enhanced chemical vapor deposition (PECVD) [1]. Here, we employed 1d3v PIC-MCC simulations to evaluate effects of amplitude modulation (AM) discharges [2] on behavior of oxygen ions in Ar/O₂ plasma. In AM discharges, the amplitude of the applied radio frequency (RF) voltage is varied sinusoidally. The results show that the O₂⁺ and O^- ion densities in the central plasma region and the ion energy distribution function (IEDF) of O₂⁺ ions incident on the grounded electrode vary with time for AM discharges. The variation widths increase with the modulation level, which indicates the modulation level is a good tuning knob to control ion density and IEDF. The results offer important information to establishing a deposition model for PECVD using AM discharges and achieving high quality SiO₂ films based on the model.

[1] Hu Li, et al., Jpn. J. Appl. Phys. 58 SEED06 (2019). [2] K. Abe, et al., Jpn. J. Appl. Phys. (2022) in press.