H. Dudaicevs et al., SURFACE MICROMACHINED PRESSURE SENSORS WITH INTEGRATED CMOS READ-OUT ELECTRONICS, Sensors and actuators. A, Physical, 43(1-3), 1994, pp. 157-163
In this paper a single chip pressure and temperature sensor system wit
h on chip electronics is presented. The capacitive pressure sensor is
fabricated using a CMOS process with additional surface micromachining
steps to form the membranes. The membrane dimensions have been optimi
zed for a pressure range of 2, 3.5, 10 and 35 bars, respectively. The
temperature sensor shows a straight linear output signal in a temperat
ure range of 0 to 70-degrees-C. For the signal processing switched cap
acitor circuits are used. The sensor signals are converted to a pulse
width modulated output signal. The silicon chip has an active area of
3.5 mm2. Between 0 and 80-degrees-C a temperature dependence of the pr
essure signal of less than 200 ppm/C referring to full scale was found
.