Wafer-Scale Encapsulated Saw Temperature and Pressure Sensors for Harsh Environments

Passive SAW sensors do not require circuitry or power and are ideal for harsh environments or rotating machinery. AlN-based thin film SAW resonators for temperature and pressure sensors have been developed in this work using AlGe wafer-scale encapsulation for device protection, pressure reference, high stability, and small size. Temperature and pressure co-testing of both sensors up to 160°C and 60 bar revealed ~1% full-scale accuracy.