Influence of power on the surface loss reaction of F radicals in a low pressure CF$_{4}$:O$_{2}$ ICP discharge

A zero dimensional modeling code Global\textunderscore kin, developed by Kushner is applied to model the CF$_{4}$/O$_{2}$ radio frequency inductively coupled plasma at applied powers of 80-300W, pressure of 25mTorr and temperature of 400K. The calculated results indicated that the Fluorine (F) is the dominant radical produced in CF$_{4}$:O$_{2}$ discharge which is lost mostly at the walls rather than in formation of F$_{2}$ molecules. We calculated the time integrated rate of F loss at the wall together with the relative contribution of wall reactions on the total loss of F corresponding to the sticking probabilities. The model predicts that although the absolute time integrated loss rates at the walls increase with power, but the relative contribution of the wall loss process decreases slightly upon higher powers. Furthermore, at lower O$_{2}$ contents (or high CF$_{4}$ contents), the relative contribution of the wall loss process is much lower because F radicals can also get lost in reactions with other plasma species such as CF$_{3}$ to form again CF$_{4}$. At equal contents of O$_{2}$ and CF$_{4}$, 35-45{\%} of the F radicals are lost at the walls, depending on the power. The numerical modeling results for CF$_{4}$ decomposition into new products are validated based on experimental data from literature.