Overview

Microelectromechanical systems (MEMS) are considered one of the major advances of industrial technologies in the past decades. MEMS technology was derived initially from the integrated circuit (IC) fabrication technologies. Now, microfabrication is a diverse spectrum of processing techniques that involve a wide range of disciplines from chemical sciences to plastic molding. As the name suggests, MEMS covers micron-sized, electrically and/or mechanically driven devices. Compared with the conventional mechanical or electrical systems, these MEMS devices are five to six orders of magnitude smaller in size. In fact, these dimensions are in the same range as the average diameter of human hair (about 50 ?m, 50 10 ^-6m, or 50 ?m). An MEMS device can be a single piece of hardware that produces outputs directly based on the inputs from external sources. The outputs can be mechanical and fluidic movement, electrical charges, analog signals, and digital signals. Often several microcomponents are integrated, such as the lab-on-a-chip device, which performs the multistage processing of the inputs and produces several different types of outputs, all in one single miniature device. The small sizes of MEMS make them portable and implantable. The manufacturing cost of MEMS is far from prohibitive because of the wide use of the batch-processing technologies that grow out of the well-developed IC industry. MEMS, therefore, offer opportunities to many areas of application, such as biomedical and information technology, that were thought not achievable using conventional devices. Estimates of the potential commercial market size were as high...