Silicon microstructuring technology

Sensors, actuators and microsystems can be realized by silicon micromachining. The structures are typically three-dimensional. To realize them, the methods known from microelectronics are not suffucient but new structuring methods which allow deep etching are applied. For that reason, the microstructing of silicon is one of the characteristic and essential tasks of the technology of microelectromechanical systems (MEMS). In this review four important microstructing techniques are described: bulk micromachining by anistropic etching, reactive ion etching, surface micromachining and porous silicon technology. The basic principles are described, the technological realization is discussed and examples for applications in the field of microsensors are given.