Ion energy and angular distributions in a dual-frequency capacitively coupled chlorine discharge

Ion energy distributions (IEDs) and ion angular distributions (IADs) of Cl₂⁺ and Cl⁺ ions in a dual-frequency capacitively coupled chlorine discharge are obtained through a particle-in-cell/Monte Carlo simulation. Since the ion transit time is less than the low-frequency period, the ions respond to the instantaneous electric field in the sheath region, which leads to bimodal IEDs for Cl₂⁺ and Cl⁺ ions. When transiting the sheath, the Cl⁺ ions experience a more collisional sheath than the Cl₂⁺ ions. The IADs of Cl₂⁺ and Cl⁺ ions at the surface are almost anisotropic. However, a secondary peak is found in the IAD of Cl⁺ ions, which can be ascribed to dissociative ionization reactions.