Ambient Temperature Compensation of Thin Film Pirani Vacuum Sensor
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A thin film Pirani vacuum sensor having a single microheater and two diode-thermistors (Th-A and Th-B) composed of pn junction diodes on the micro-air-bridge (MAB) is fabricated by micromachining technologies. A method to eliminate the ambient temperature effects based on double pulse-heating (pulse duration: 125ms) up to two different temperatures, <i>T<sub>h</sub></i> and <i>T<sub>l</sub></i>, above the room temperature in vacuum sensing is proposed. Pulse-heating has also a merit to prevent temperature increase of the sensor chip. It is demonstrated that the Pirani gauge with a cantilever type MAB structure can almost compensate the ambient temperature effects by double pulse-heating. A method to correct the errors due to the non-linearity in the I-T relationship of the diode-thermistor as a very sensitive temperature sensor is also described.
- The Journal of the Institute of Electrical Engineers of Japan
The Journal of the Institute of Electrical Engineers of Japan 127(3), 136-139, 2007-03-01
The Institute of Electrical Engineers of Japan