SURFACE MICROMACHINED PRESSURE SENSORS WITH INTEGRATED CMOS READ-OUT ELECTRONICS

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 .