Design of an Integrated Humidity Sensor with Digital Output in Double Metal CMOS Technology

Abstract

We present an integrated humidity sensor system designed for the 2μm, 5V, double-metal CMOS technology CMN20a of VLSI Technology provided through the multiproject wafer service of the Swiss Center of Electronics and Microtechnology CSEM. The design includes a humidity sensitive capacitor, a reference element, signal processing circuits, and digital control and conversion circuits, all integrated on the same chip. The sensor specific analog circuitry has been designed using the analog design expert system IDAC developed by CSEM. Test results on a previous humidity sensitive capacitor in CMOS technology are reported.