11.1. Introduction: MEMS

MEMS is an abbreviation for "micro electro-mechanical system" [1]. These devices feature the integration of mechanical elements, sensors, actuators and operating electronics on a common silicon substrate with the use of microfabrication technology [2].

While the electronic circuits (either analog or digital) are fabricated using integrated circuit process sequences (CMOS, BiPolar or BiCMOS processes), the micromechanical part is made by micromachining. Micromachining techniques selectively etch away parts of the silicon wafer or add new structural layers to form the required mechanical and electromechanical devices [3].

Microelectronic integrated circuits (ICs) handle the signal processing, while micromachined parts serve as sensors and actuators which allows the microsystems to sense and control the environment.

Components of MEMS are:

• microsensors;

• microactuators;

• microelectronics;

• microstructures.

Since MEMS devices are manufactured by batch fabrication techniques, similar to ICs, unprecedented levels of functionality, reliability and sophistication can be placed on a small silicon chip at a relatively low cost. With thin films, the photolithographic fabrication procedures make it possible to build extremely small, high precision mechanical structures using the same processes that have been developed for electronic circuits [4].

MEMS promises to revolutionize nearly every product category by bringing together silicon-based microelectronics with micromachining technology, thereby enabling the realization of a complete system-on-a-chip [5].

MEMS technology is enabling new discoveries in science and engineering such as the polymerase chain reaction (PCR) microsystems for DNA amplification and identification,...