Ultra-High Sensitivity Surface-Micromachined Capacitive Differential Pressure Sensor for Low-Pressure Applications

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 $\mu \text{m}$ with a thickness of 1 $\mu \text{m}$ and the chip size is $1.5\times 2\times 0.6$ 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]