TITLE:
Output Drifting of Vacuum Packaged MEMS Sensors Due to Room Temperature Helium Exposure
AUTHORS:
Douglas Sparks, Jay Mitchell, Sangwoo Lee
KEYWORDS:
MEMS; Helium; Resonator; Pressure Sensor; Pirani Gauge
JOURNAL NAME:
Journal of Sensor Technology,
Vol.3 No.4,
December
20,
2013
ABSTRACT: Exposure of absolute pressure sensors, resonant microtube density, binary concentration sensors and chip-scale vacuum packaged pirani gauges to room temperature helium resulted in a gradual drift in sensor output. No effect was found for differential pressure sensors and pirani gauges vacuum packaged with ceramic or metal packages. The observed results apply to other vacuum packaged MEMS devices such as gyroscopes, voltage controlled oscillators, infrared and Coriolis mass flow sensors. Potential causes for this loss of hermeticity are discussed as well as application limitations for MEMS sensors.