Gas Pressure Measurement Using Micro-Corona-Discharging Effect In Surface Acoustic Wave Resonators

This paper reports a gas pressure sensor using surface acoustic wave resonator (SAWR) based on both the fieldinduced electron emission and the micro-corona-discharging (MCD) phenomena. With the micron-scale fingergap of electrodes covered with SiO2 passivation layer, the enhanced field-effect emission (FEE) at electrodes result in the micro-corona-discharging and thus the change in the dynamic resistance of SAWR. A high Q-factor SAWR was fabricated on ST-cut quartz substrate using microelectronics processing technology, and the gaspressure-dependent return-loss was tested, and the MCD theory and the equivalent circuit model of SAWR were used to analyze the test results. Under argon pressure range from 0 to 601 kPa, the dynamic resistance of the SAWR varies from 24.569 to 41.589 Omega at 25 degrees C. The resistance rate reaches 69.3%, which is far higher than that of traditional piezoresistive pressure sensors. At the same time, the oxygen pressure was also tested by the SAWR as a comparison. The SAW-based gas pressure sensors have the potential for measurement of the superhigh pressure.