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

Abstract

The wet and dry etching behavior of La 3Ga 5.5Nb 0.5O 14 is reported. The ultimate application for this material is as crystal resonators whose operating frequency is inversely proportional to sample thickness. Reaction-limited wet etching in HCl or HF at ≥25°C, or HNO 3 at ≥60°C produced removal rates up to 9500 Å·min −1 (HCl at 65°C), with surface root-mean-square (RMS) roughnesses about a factor of two higher than on an unetched control sample. Dry etching in Cl 2-based plasmas produced removal rates up to 950 Å·min −1, with surfaces RMS values also about a factor of two higher than on control samples. Significant surface roughening occurred during dry etching when higher ion fluxes were used.