A model for reactive ion etching of PZT thin films

In this work, a simplified model for the discharge kinetics and surface chemistry of r.f. discharges containing CF,, CHF, and Ar gas mixtures suitable for lead zirconate-titanate (PZT) etch rate simulation is presented. The electron density and the fraction of power dissipation in the discharge bulk, in the sheaths and due to the oscillating sheath boundaries were calculated by an electron kinetics model for given etching parameters. A Maxwellian electron energy distribution was assumed. For a parallel plate etching reactor with a plug gas flow parallel to the electrode surface, the ion energy flux determining the PZT etch rate was calculated. The fraction of power dissipated by ion bombardment was about 80%. A weak dependence of the ion energy flux on gas composition was obtained. (C) 1999 Elsevier Science S.A. All rights reserved.