From cantilever beams to multisensor microsystems

Henry Baltes, Oliver Brand, D. Lange, C. Hagleitner, M. Zimmermann

Physical Electronics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland

Our first cantilever-based chemical sensor has been demonstrated in 1992. This was a mass-sensitive humidity sensor using silicon oxide beams coated with polyimide [T. Boltshauser, M. Schonholzer, O. Brand, H. Baltes: Micromech. Microeng. 2 (1992) 205-207]. In this talk, however, our most recent examples of CMOS compatible cantilever-based chemical and force sensors are reviewed. The first is a single-chip CMOS resonant beam gas sensing system with on-chip self excitation for the detection of volatile organic compounds with sub-pg mass resolution. This device has recently been incorporated in a handheld multisensor system exhibited at the Hannover Messe in April 2001. The second example is a CMOS-based 10-cantilever array for constant force parallel scanning atomic force microscopy (AFM) with beams, thermal actuators, piezoresistive sensors, and their circuits combined on one chip. In both cases, the system integration with on-chip circuitry is decisive for performance.