Etching characteristics of Pb(Zr,Ti)O3 thin films in Cl2/Ar and CF4/Ar inductively coupled plasmas: effect of gas mixing ratios

The investigation of Pb(Zr,Ti)O3 (PZT) etching mechanism in both Cl2/Ar and CF4/Ar plasmas was carried out. It was found that, in CF4/Ar plasma, etch rate has a maximum at 80% Ar, while for Cl2/Ar plasma, etch rate keeps a constant value up to 40% Ar. The volume densities and fluxes of active species in both gas mixtures derived from the zero-dimensional (0-D) plasma models change in same manner while a nonmonotonic behavior was not observed. However, the analysis of surface kinetics confirmed the possibilities of nonmonotonic etch rate behavior in both gas mixtures due to a concurrence of physical and chemical pathways in ion-assisted chemical reaction.