A CMOS micromachined capacitive tactile sensor with compensation of process variations

This paper presents a standard-CMOS-fabricated capacitive tactile sensor with high sensitivity and a sensing circuit with compensation of process variations. Both of the sensor and sensing circuit are fabricated on a single chip by a TSMC 0.35μm CMOS MEMS technology. In order to create high sensitivity of the sensor for sensing circuit, a T-shaped protrusion is proposed. This sensor is constituted by the metal layer and the dielectric layer without extra thin film deposition, and can be completed with few simple post-processing steps. With the fully differential correlated double sampling capacitor-to-voltage converter (CDS-CVC) and reference capacitor correction, process variations are compensated. The measured sensitivity of the sensing circuit is 18mV/fF.