An investigation of the SrBi2Ta2O9 (SBT) etching mechanism in a Cl-2/Ar plasma was carried out. Experiments showed that an increase of the Ar mixing ratio under constant pressure and input power conditions leads to increasing an etch rate of SBT, which reaches a maximum value when the Ar is 80% of the gas. The modeling of volume kinetics using the measured electron temperature and electron density indicated monotonic changes of both densities and fluxes of active species such as chlorine atoms and positive ions. Nevertheless, an analysis of surface kinetics in the framework of an ion-assisted etching mechanism confirms the possibility of nonmonotonic etch rate behavior due to the concurrence of physical sputtering and chemical etching activated by ion bombardment. (C) 2003 American Vacuum Society.