Study of Surface Reaction Probability of CFx Radicals by Trench Deposition Method

The surface reaction probabilities of CF x radicals are determined with a trench deposition method for C:H:F films deposited by the discharge in a CF4/H2 mixture. It is found that the overall sticking probability of CF x is β=0.1-0.2 and 0.2 for substrates placed on the reactor wall and on the earth electrode, respectively. The respective roles of the sticky and less-sticky radicals (probably CF and CF2, respectively) are derived by making use of the film profiles, and their sticking probabilities are found to be about 1.0 and 0.05, respectively. Moreover, it is shown that the method is applicable to estimate the contribution of the ion-enhanced deposition, e.g., 50-60% of the film thickness for the present condition of the gas flow ratio of CF4/H2=19/16 at the rf discharge pressure of 0.4 Torr.