Abstract
In this work, we discuss the effects of component ratios on plasma characteristics, chemistry of active species, and silicon etching kinetics in CF(4) + O(2), CHF(3) + O(2), and C(4)F(8) + O(2) gas mixtures. It was shown that the addition of O(2) changes electrons- and ions-related plasma parameters rapidly suppresses densities of CF(x) radicals and influences F atoms kinetics through their formation rate and/or loss frequency. The dominant Si etching mechanism in all three cases is the chemical interaction with F atoms featured by the nonconstant reaction probability. The latter reflects both the remaining amount of fluorocarbon polymer and oxidation of silicon surface.