Electron dynamics of power absorption in capacitive radio-frequency CF₄ plasmas operating in the striation mode

The electron dynamics of power absorption in CF4 capacitive radio-frequency discharges operating in striation mode are investigated using particle-in-cell/Monte Carlo collision simulations. Our analysis, based on the Boltzmann term method, shows that non-local collisional power absorption significantly exceeds Ohmic power absorption in the bulk plasma under striation mode. This dominance of non-local collisional power absorption arises from the temporal evolution of the spatially modulated electric field, which induces periodic compression and expansion of the electron fluid, thereby facilitating this absorption mechanism throughout the bulk region. Test particle trajectory calculations confirm that electrons fully participate in non-local collisional power absorption as they traverse the bulk plasma. A subset of low-energy electrons can be trapped in the striated electric field with multiple rebounds, during which power absorption is negligible. These findings highlight the critical role of the modulated electric field in enhancing the non-local collisional power absorption in striation mode.