Evaluation of langasite (La3Ga5SiO14) as a material for high temperature microsystems

Lanthanum gallium silicate (langasite, La3Ga5SiO14) is a piezoelectric material with promising properties for micro-electromechanical applications at high temperatures. So far it has been used for SAW and BAW devices. This paper reports on the possibility of fabricating microstructures in langasite by wet chemical etching. The etching behavior of different chemicals applying different mask materials is investigated. As a first demonstrator a cantilever beam in langasite is produced showing the possibility of MEMS in langasite. The mechanical velocity spectrum and the electrical spectrum are recorded. Elevated temperatures are applied to the beam and another spectrum is recorded proving the functionality up to 700 °C.