Reactive ion etching of lead zirconate titanate and ruthenium oxide thin films using CHClFCF.sub.3 or CHCl.sub.2 CF.sub.3 as an etch gas

A method of reactive ion etching both a lead zirconate titanate ferroelectric dielectric and a RuO.sub.2 electrode, and a semiconductor device produced in accordance with such process. The dielectric and electrode are etched in an etching gas of O.sub.2 mixed with either CHCl.sub.2 CF.sub.3 or CHClFCF.sub.3.