A MicroPirani Pressure Sensor Based on the Tungsten Microhotplate in a Standard CMOS Process
Jiaqi Wang; Zhenan Tang; Jinfeng Li; Fengtian Zhang
Industrial Electronics, IEEE Transactions on
Volume 56, Issue 4, April 2009 Page(s):1086 - 1091
Digital Object Identifier 10.1109/TIE.2009.2012421
Summary:This paper reports a tungsten microhotplate fabricated in a standard CMOS process and the implementation of a MicroPirani pressure sensor with it. A monolithic constant-current circuit including an operational amplifier is used to bias the tungsten microhotplate to measure the gas pressure. The sensor shows a linear response to the gas pressure in the range of 1-100 Pa when driven by a constant current of 7 mA. In this regime, the sensitivity of the sensor is 0.23 mV/Pa, the linearity is 4.95%, and the hysteresis is 8.69%. The MicroPirani pressure sensor in this paper can be used in a medium-vacuum measurement. Because tungsten in a standard CMOS process has a large temperature coefficient regardless of the different manufacturing processes, the design of the tungsten microhotplate can be applied to other thermal-based sensors, even in different standard CMOS processes.
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