Microsensors for physical signals: Principles, device design, and fabrication technologies
Microsensors are miniaturized devices, fabricated using silicon-based and related technologies, that convert input physical and chemical signals into an output electrical signal. The key driving force in microsensor research has been the integrated circuit (IC) and micromachining technologies. The latter, in particular, is fueling tremendous activity in micro-electromechanical systems (MEMS). In terms of technology and design tools, MEMS is at a stage where microelectronics was 30 years ago and is expected to evolve at an equally rapid pace. The synergy between the IC, micromachining, and integrated photonics technologies can potentially spawn a new generation of microsystems that will feature a unique marriage of microsensor, signal-conditioning and -processing circuitry, micromechanics, and optomechanics possibly on a single chip. In this paper, the physical transduction principles, materials considerations, process-fabrication technologies, and computer-aided-design (CAD) tools will be reviewed along with pertinent examples drawn from our microsensor research activity at the Microelectronics Laboratory, University of Waterloo.