A Micromachined Resonant Low-Pressure Sensor With High Quality Factor

Abstract

This article presents a micromachined resonant low-pressure sensor with high quality factor. In this sensor, an island-diaphragm structure was developed, translating low pressures under measurements to frequency shifts of resonators, and improving quality factors of resonators by eliminating modal interferences between resonators and the pressure-sensitive diaphragm. Numerical simulations were conducted, confirming that the developed resonant low-pressure sensor can work properly in the measurement range without modal interference due to the island-diaphragm structure. The fabrication process of the developed resonant low-pressure sensor including key steps of deep reactive ion etching, resonator release and anodic bonding was conducted in this study. Experimental characterization showed high quality factors of resonators (>30000), which were significantly better than previous study (<10000). Moreover, low fitting errors (within ±2 Pa), low hysteresis (within ±2 Pa) and high accuracies (measurement errors within ±2 Pa) were also characterized in the low pressure range of 0.1 kPa-1 kPa and the temperature range of −40 °C–60 °C, validating the high performances of the developed resonant low-pressure sensor.