Thermoelastic effects in Pt IDTs. Impact on the behavior of high-temperature LGS-based SAW devices

Delay lines based on Pt electrodes and the LGS orientations with (0°, 138.5°, 26.7°) and (0°, 22°, 31°) Euler angles are experimentally investigated up to 700°C. Big discrepancies between the frequency-temperature laws for devices made with different Pt relative thicknesses are observed, in particular on the (0°, 22°, 31°) orientation. Simulations show that this phenomenon could be related to the large thermoelastic effects happening in Pt electrodes when the temperature rises.

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