Micro-Electro-Mechanical Systems, or MEMS, is a technology consisting of miniaturized mechanical and electro-mechanical elements such as devices and structures that are made up by using the techniques of microfabrication. Physical dimensions of MEMS devices can vary from well below one micron to several millimeters. Likewise, the types of MEMS devices can vary from relatively simple structures having no moving elements, to extremely complex electromechanical systems with multiple moving elements under the control of integrated microelectronics.
The one main criterion of MEMS is that there are at least some elements having some sort of mechanical functionality whether or not these elements can move.
MEMS consists of miniaturized structures, sensors, actuators, and microelectronics, including micro sensors and micro actuators. Micro sensors are typically the devices that convert a measured mechanical signal into an electrical signal. They can measure temperature, pressure, chemical species, magnetic fields and radiations among other characteristics.
The real potential of MEMS starts to become fulfilled when these miniaturized sensors, actuators, and structures can all be merged onto a common silicon substrate along with integrated circuits like microelectronics. MEMS can be merged not only with microelectronics, but with other technologies such as photonics, nanotechnology, etc. thereby increasing its usage to a widespread application!