A Surface Acoustic Wave Pressure Sensor Based on Micro-Corona-Discharging Effect

摘要

This paper proposes a gas pressure sensor based on the field-induced electron emission and micro-corona phenomenon on the metal interdigitated (IDT) electrodes of the surface acoustic wave resonator (SAWR). The SAWR was fabricated on ST-cut quartz substrate with aluminum IDT electrodes and reflectors. With the micron-scale finger-gap of IDT electrodes covered with SiO2 passivation layer, the enhanced field-electrons emission from the edges of IDT fingers result in the micro-corona-discharging and thus the change in the dynamic resistance of SAWR. A high Q-factor SAWR was fabricated and the pressure-dependent S11 were tested and analyzed using this SAWR. Under gas pressure range from 0 ~ 601 kPa, the dynamic resistance of the SAWR varies from 24.569 Ω to 41.589 Ω at 25°C. The resistance rate reaches 69.3%, which is far higher than that of traditional piezoresistive sensors.