Measured versus predicted high temperature langatate behavior up to 900°C

This paper reports on surface acoustic wave (SAW) device measurements from room temperature to 900degC along six different orientations on langatate (LGT) wafers. The temperature behavior measured is compared to numerical predictions based on elastic constants extracted at high temperatures using resonant ultrasound spectroscopy techniques. SAW delay lines were fabricated on LGT wafers prepared at the University of Maine using 100 nm platinum-rhodium-zirconia electrodes capable of withstanding temperatures up to 1000degC. The frequency responses were used to extract the SAW velocities and temperature coefficients of delay. The results reported verify the existence of temperature compensated orientations at high temperature, which reinforce the interest in using LGT as a high temperature piezoelectric substrate.