LOW-DRIFT ODOUR AND VAPOUR RATIOMETRIC RESISTIVE ELEMENTS FOR ANALOGUE CMOS SMART SENSORS

摘要

Five different designs of conducting polymer resistor networks are proposed based upon a ratiometric principle. This overcomes the problems caused by both the wide range of polymer resistance values (i.e. 10 Ω to 100 kΩ) with standard interface circuitry, and their significant temperature dependence. Discrete devices have been realised by the electrochemical deposition of conducting polymers across the resistive elements. Their response to ethanol vapour in air is reported and improvements in device performance observed. A CMOS version has also been designed, based upon an 0.8 μm AMS silicon process, with integrated thermodiode and heater and is suitable for spray coated polymer resistors.