Microelectromechanical structures in langasite (La3Ga5SiO14) by wet chemical etching

Lanthanum gallium silicate (langasite, La₃Ga₅SiO₁₄) is a new 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 was investigated. Further, the effect of doping on the etching behavior was studied. As a first demonstrator a cantilever beam in langasite has been produced showing the possibility of MEMS in langasite. The resonance spectrum of this device was recorded at temperatures up to 600°C.