Bulk acoustic wave resonators for infrared detection applications

This paper reports on the fabrication and application of Y-cut temperature-sensitive quartz resonators for infrared detection applications. The high thermal sensitivity of the Y-cut quartz crystal (90 ppm/K) and the high quality factor (>10,000) of the piezoelectric bulk acoustic wave resonators fabricated from such crystals enable the application of these devices as extremely sensitive uncooled thermal infrared (IR) detectors. We report the fabrication and performance of inverted mesa devices with 1 mm diameter and 18 mum thickness with 6.8 kHz/K of temperature sensitivity at 90 MHz.