Surface morphology and removal rates for dry- and wet-etched novel resonator materials Part I: La Ga Ta O 3 5.5 0.5 14

La3Ga5.5Ta0.5O14 shows promise for high temperature, high frequency crystal resonator applications. We report on two methods for thinning wafers of this material. Using wet chemical etching, we found that HCl- or HF-based solutions produced etching at room temperature, while HNO3 and H3PO4 produced practical rates at G708C. In all of these solutions, the etching was reaction-limited with activation energies )14 kcalPmoly1. Some degree of surface smoothing was achieved with HCl etching at elevated temperatures. The near-surface stoichiometry was unaffected by the wet etch treatments. Using dry etching, we found that Cl2-based discharges produced rates -950 A° Pminy1 under all conditions, with Cl2rAr maintaining the best surface morphology. q2000 Elsevier Science B.V. All rights reserved