Ultra-High Sensitivity Surface-Micromachined Capacitive Differential Pressure Sensor for Low-Pressure Applications
Tapio Pernu, Jaakko Saarilahti, Jukka Kyynäräinen, Teuvo Sillanpää
Abstract
An ultra-high sensitivity surface-micromachined capacitive differential pressure sensor and capacitance bridge readout circuit, with amplitude balancing for differential low-pressure gas measurement applications, was designed, fabricated, and characterized. The sensor membrane has a diameter of 800 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> with a thickness of 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> and the chip size is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.5\times 2\times 0.6$ </tex-math></inline-formula> mm3. The characterized sensor pressure range is 0–2000 Pa, with a full-scale capacitance difference span of 0.95 pF. Typical pressure error within the pressure range of 0–2000 Pa is ±0.5%, and the temperature coefficient is 0.044%/°C, both respectively from the pressure reading. [2022-0017]