Integrated chemical microsensor systems in CMOS-technology

The aim in utilizing microfabrication techniques and CMOS technology for chemical sensors is to devise more intelligent, more autonomous, more integrated, and more reliable gas sensor systems at low costs in a generic approach. Since the sensor market is strongly fragmented, i.e., there exists a large variety of applications with different needs and sensor requirements, a modular approach or "toolbox strategy" relying on CMOS as platform technology was identified as a very promising approach. The application then dictates the microsensor system architecture and the nature of its components: As soon as the target analytes and their concentrations as well as the boundary conditions of detection are specified, the optimum transducer, the necessary driving and signal conditioning circuitry, as well as interface and communication units can be selected from the CMOS-toolbox, and the different modules can then be combined to arrive at a custom-designed monolithic CMOS microsensor system. Several examples of monolithically integrated chemical microsensor systems are presented. The evolution from single transducers, which are integrated with the necessary driving and signal conditioning circuitry, to monolithic multi-sensor arrays and fully developed systems with on-chip sensor control and standard interfaces is shown.