Principles and Applications of Ubiquitous Sensing

Chapter 9Microelectromechanical Systems

A book about sensors will not be complete without consideration of microelectromechanical systems (MEMS). However, due to the vastness of the subject and its multi-disciplinary nature, a single chapter may not do it justice. Devoting to the subject more than a single chapter, on the other hand, makes the book unnecessarily disproportional. Moreover, there are a number of books (for example, by Bao 2005; Korvink and Paul 2010; Liu 2010; Lyshevski 2002; Maluf and Williams 2004) and articles (for example by Fedder et al. 2008; Judy 2001; Kaajakari et al. 2009; Reina et al. 2008) that readers wishing to get an in-depth insight may refer to. With this cautionary remark, this chapter is intended to give an introduction to MEMS and the most important design, fabrication, and integration processes. It wil also introduce some of the most representative and state-of-the-art MEMS sensors.

MEMS represent, as their name suggests, the miniaturised version of macro systems that have mechanical and electrical components. However, this description is not adequate, since the systems may also have optical, thermal, chemical, magnetic, biological, and other components (Challa et al. 2008; Krüger et al. 2002; Ma and Kuo 2003; Staples et al. 2006; Waggoner and Craighead 2007). The most pervasive MEMS are sensors, actuators, and optical devices, (such as mirrors, waveguides, and splitters. These systems have a wide range of applications owing to their small ...