Micromachined quartz resonator-based high performance thermal sensors

This paper presents the design, fabrication, and characterization of temperature sensitive quartz resonators fabricated using heterogeneous integration methods for realizing high-density, thermal conductance fluctuation limited thermal sensors for infrared imaging and biochemical sensing applications. An integrated quartz sensor array using CMOS-compatible micromachining techniques has been designed and fabricated. 241 MHz micromachined resonators from Y-cut quartz crystal cuts were fabricated with a temperature sensitivity of 22.162 kHz/°C. Infrared measurements on the resonator pixel resulted in a noise equivalent power (NEP) of 3.90 nW/Hz^1/2, detectivity D* of 9.17 ×10⁷ cmHz^1/2/W, and noise equivalent temperature difference (NETD) in the 8-12 μm wavelength region of 4 mK and a response time of <;30 Hz. In a unique new application a remotely coupled thermal sensor configuration was used to monitor biochemical reactions in real time.