Investigation on the Thin Film Pirani Vacuum Sensor Using A Constant Voltage Drive-Mode Diode-Heater
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A thin film Pirani vacuum sensor having a single micro-heater and two diode temperature sensors composed of pn junction diodes on the sensing cantilever, fabricated by micromachining technologies, is driven by a constant applied voltage driving mode using the diode heater to enhance the pressure sensitivity. In these experiments new diode-sensors are used as a temperature sensor, which has a proportional output signal voltage Δ<i>V</i> to the absolute temperature <i>T</i> as Δ<i>V</i>=α<i>T</i>. These new type diode-sensors are useful to measure the temperature difference Δ<i>T</i> between these diode sensors. In this pressure sensing the null detection method is adopted for accurate measurements. In the low pressure range such as 1×10<sup>-3</sup>-1×10<sup>0</sup> Pa the diode-thermistor will be useful because of its higher temperature sensitivity. It is demonstrated that this thin film Pirani vacuum sensor can measure the wide pressure range of 1×10<sup>-3</sup> to 1×10<sup>5</sup> Pa, which is about 2 order wider pressure range than that of usual Pirani gauge.
- The Journal of the Institute of Electrical Engineers of Japan
The Journal of the Institute of Electrical Engineers of Japan 128(5), 209-213, 2008-05-01
The Institute of Electrical Engineers of Japan