High Temperature SAW Gas Sensor on Langasite

Novel Surface Acoustic Wave (SAW) devices using the new langasite (LGS) family of crystals have been designed, fabricated, and tested for high temperature (up to 750°C) gas sensor applications. The devices were fabricated using platinum (Pt) and palladium (Pd) thin film technology and were mounted in a high temperature sealed stainless steel chamber for gas testing. The high temperature SAW sensors have been exposed to temperatures from 250°C to 750°C and cycled more than ten times in that temperature range over periods from two to six weeks. Gas sensing of C2H4 in N2 and H2 in N2 with baselines of O2 and N2 on the LGS SAW devices has been performed from 250°C to 550°C and is reported for the first time in this paper