Thin quartz resonators as a detector element for thermal infrared sensors

This work describes the manufacturing technology and packaging of a single-crystal quartz sensor with a thickness of 5 µm. The temperature dependence of the resonance frequency of quartz resonators can be used for thermal radiation sensors with a high signal-to-noise ratio. The sensitive element, in the form of a bowl or a cantilever, is ion beam etched and must be able to vibrate freely. Impedance measurements show the temperature-dependent vibration of the resonators. For higher frequencies, scattering parameters are measured using a vector network analyzer. The cantilever achieves a higher vibration amplitude than the bowl, although with many secondary resonances. The temperature coefficient of the resonance frequency is determined to be around 90 ppm K−1.