The Role of Chlorine Atoms in Etching Silicon in the Plasma of CF2Cl2/O2

The paper describes a model of plasma chemical etching of silicon in CCl2F2/O2plasma with teflon coating of the reactor walls. It is established that the chlorine atoms lead to a shift in the maximum of the dependence of the etching rate of silicon on the oxygen content in the gas mixture to ~90%, in comparison with fluorine containing plasmas. It is shown that the proposed model of the process explains all the currently known experimental data for CCl2F2/O2plasma. The model is applicable to other chlorine containing mixtures, at least when silicon is etched.