Dynamics of electron power absorption in capacitive radio-frequency CF4 plasmas operating in the striation mode

Abstract

The dynamics of the electron power absorption in radio-frequency CF4 capacitively coupled plasmas operating in the striation mode is investigated based on a particle-in-cell/Monte Carlo collision model. In the striation mode, the mean electron energy within the bulk plasma exhibits a spatially modulated structure with high-energy peaks. Using the Boltzmann term analysis method, we demonstrate that non-local collisional power absorption, rather than Ohmic heating, dominates the formation of these peaks. Through test particle trajectory calculations, we demonstrate that most of the energetic electrons can traverse the spatially modulated electric field and this transportation process is responsible for most of the non-local collisional power absorption. Some low-energy electrons undergo multiple rebounds and are confined within the spatially modulated field; however, the power absorption by these electrons is negligible compared to ones capable of passing through the modulated field.