PLZT thin film etching using plasma techniques

The feasibility of patterning PLZT thin films by chemical plasma etching techniques was investigated using HCl and CF₄ in a DC hollow cathode discharge system. The thin films were deposited on silicon substrates using either RF magnetron sputtering or solution deposition methods. Etch rates and variations in film stoichiometry were measured as a function of substrate temperature and etching gas composition. Results show that films were etched in either HCl or CF₄, but substrate temperatures above 200°C were required before measurable etch rates occurred. The film stoichiometry varied as the etching system parameters were changed, showing considerable variation with substrate temperature and process gas mixture. Etch rates for the solution-deposited films in a CF₄ plasma were an order of magnitude larger than for the sputter-deposited films. The highest etch rate for sputtered films was obtained using a combination of HCl and CF₄, resulting in an etch rate six times greater than those measured using either gas alone