Title :
Flexible Conformal Micromachined Absolute Pressure Sensors
Author :
Ahmed, Moinuddin ; Chitteboyina, Murali ; Butler, Donald P. ; Celik-Butler, Zeynep
Author_Institution :
Dept. of Electr. Eng., Univ. of Texas, Arlington, TX, USA
Abstract :
The fabrication and characterization of micromachined piezoresistive absolute pressure sensors in a flexible substrate is presented. A suspended aluminum oxide diaphragm containing nichrome (Ni-80%/Cr-20%) piezoresistive sensors backed by a vacuum cavity was utilized to form the sensor. The piezoresistors were placed in a half-Wheatstone bridge geometry to provide a linear response and thermal stability. The average value of the gauge factor of nichrome was measured to be 1.95. The average normalized Hooge coefficient K1/f was found to be 4.64×10-11 for the nichrome piezoresistors. The pressure sensors displayed an average sensitivity of 1.25 nV/Pa and average value of noise equivalent pressure (NEPr) of 7.44 kPa in the bandwidth of 1-10 Hz in the 1/f -noise limited regime. In the Johnson noise-limited regime, the NEPr was found to be 10 Pa in a 1-Hz bandwidth.
Keywords :
1/f noise; bridge circuits; diaphragms; micromachining; microsensors; piezoresistive devices; pressure measurement; pressure sensors; resistors; thermal noise; 1/f-noise limited regime; Johnson noise-limited regime; NEPr; average normalized Hooge coefficient; bandwidth 1 Hz to 10 Hz; flexible conformal micromachined piezoresistive absolute pressure sensor; gauge factor measurement; half-Wheatstone bridge geometry; nichrome; noise equivalent pressure; piezoresistor; pressure 10 Pa; pressure 7.44 kPa; suspended aluminum oxide diaphragm; thermal stability; vacuum cavity; Cavity resonators; Electrical resistance measurement; Noise; Pressure measurement; Sensor phenomena and characterization; Voltage measurement; Absolute pressure sensor; flexible substrate; noise equivalent pressure; noise equivalent pressure.;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2015.2405071
