Digital compensated capacitive pressure sensor using CMOS technology for low-pressure measurements

• Published in: Sensors and actuators. A, Physical Physical, 1992, Vol.34 (2), p.173-177
• Main Authors: Nagata, Tomio, Terabe, Hiroaki, Kuwahara, Sirou, Sakurai, Shizuki, Tabata, Osamu, Sugiyama, Susumu, Esashi, Masayoshi
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; Transducers
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/0924-4247(92)80189-A

A capacitive pressure sensor with digital output for low-pressure measurements has been fabricated using CMOS technology. The sensor output is compensated and adjusted by a newly developed method. The sensor has a hybrid configuration of an integrated sensor chip and a digital IC chip. Because of this configuration, the thermal sensitivity shift and thermal zero shift of the output are adjusted at the sensor chip, while the offset and full-scale span of the output are adjusted at the digital IC chip, independently. By using the new compensation and adjustment technique, a thermal sensitivity shift of 0.026% FS/°C and thermal zero shift of 0.013% FS/°C for a pressure range of 0-200 mm H 2O (0-20.39 Pa) and a temperature range of 25–75 °C have been obtained. These characteristics using the new compensation method are about 1/7 and 1/4 of those obtained by using a conventional method. Furthermore, a humidity countermeasure is proposed.