Surface-Micromachined CMOS-Mems Capacitive Pressure Sensor with Enhanced Sensitivity for Low-Pressure Applications

We present a grid-type MEMS capacitive pressure sensor fabricated using a 0.18 μm 1P6M CMOS processes combined with a surface micromachining technique. The innovative grid-type sensor design offers a better sensitivity over conventional planar structures, achieving a 25% improvement in mechanical sensitivity, as proved by finite element analysis (FEA) simulations. Experimental evaluations under air pressure loads up to 2.7 kPa show that the developed CMOS-MEMS sensor achieves a sensitivity of 24 fF/kPa with a nonlinearity of less than 2% Full Scale Span (FSS). These results confirm the effectiveness of the proposed sensor design and fabrication strategy for low-pressure applications requiring high precision, good sensitivity, and excellent linearity.