Abstract

Many methods have been proposed for etching ferroelectric thin film, such as PLZT and BaTiO₃ for optical waveguide modulator applications, including wet chemical etching, chemical plasma etching, and reactive ion beam milling. In this paper, etching of the film with plasma by using pure argon is discussed and the experimental results on etching PLZT thin films are reported. Since a strictly physical process is involved during etching, because of the chemical inactivity between argon and thin film material, this etching process gives the advantage of preserving the stoichiometry of the thin film material. It turns out that the etching rate is lower than that of the chemical plasma etching, but a much better channel edge quality that is more suitable for optical waveguide applications is produced. SEM micrographs and optical waveguiding results will be presented. To address the issue of photoresist hardening problem during the long etching, a metal mask is used. The advantages and drawbacks of the etching method for fabrication channel waveguide modulators will be discussed.

© 1992 Optical Society of America