title: A CMOS micromachined capacitive tactile sensor with integrated readout circuits and compensation of process variations.
abstract: This paper presents a capacitive tactile sensor fabricated in a standard CMOS process. Both of the sensor and readout circuits are integrated on a single chip by a TSMC 0.35 μm CMOS MEMS technology. In order to improve the sensitivity, a T-shaped protrusion is proposed and implemented. This sensor comprises the metal layer and the dielectric layer without extra thin film deposition, and can be completed with few post-processing steps. By a nano-indenter, the measured spring constant of the T-shaped structure is 2.19 kNewton/m. Fully differential correlated double sampling capacitor-to-voltage converter (CDS-CVC) and reference capacitor correction are utilized to compensate process variations and improve the accuracy of the readout circuits. The measured displacement-to-voltage transductance is 7.15 mV/nm, and the sensitivity is 3.26 mV/μNewton. The overall power dissipation is 132.8 μW.
authors.forename: Tsung-Heng
authors.initials: TH
authors.lastname: Tsai
authors.forename: Hao-Cheng
authors.initials: HC
authors.lastname: Tsai
authors.forename: Tien-Keng
authors.initials: TK
authors.lastname: Wu
mesh_terms: D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D055616:Microtechnology / Q000295:instrumentation*; D012666:Semiconductors