Design and fabrication of high-Q langasite resonator arrays for high temperature applications

The design of piezoelectrically actuated plano-convex shaped resonators in lanthanum gallium silicate (langasite, LGS) was investigated and improved by finite element simulations. Especially effects of shape and clamping were simulated. Further, devices that demonstrate the working principle have been fabricated. The membrane arrays have shown operating temperatures of more than 700degC and are applied as high temperature gas detecting devices by means of CeO₂ sensor films. The special shape of the resonators causes an energy confinement and improves the quality factor at high temperatures. Wet etching, dry etching and masking technologies had to be applied for the fabrication. Simulation results could be confirmed by measurements.