Capacitive pressure sensor with monolithically integrated CMOS readout circuit for high temperature applications

Abstract

An integrated capacitive surface micromachined pressure sensor for high temperature applications was developed and characterized to work at temperatures up to 250 °C. The sensor and the CMOS readout circuit are processed on separation by implantation of oxygen (SIMOX) substrates. The readout circuit is programmable and allows calibration of linearity, offset and output range. The performance of a 20 and 50 bar sensor is discussed. Even without active temperature compensation the offset temperature coefficient (TCO) referred to full scale output (FSO) is less than 0.03%/°C between 25 and 150 °C and less than 0.09%/°C between 150 and 250 °C. The compensated linearity error is less than 0.4% FSO.