MEMS relate to a technology of very small electrically driven mechanical devices. MEMS converges at the nano-scale with NEMS and nanotechnology in general. MEMS are sometimes referred to as micro-machines or as micro systems technology (MST). MEMS include components between 1 to 100 micrometers in size, while MEMS devices can generally range in size from about 20 micrometers and larger. NEMS devices are smaller still. At the size scales of MEMS devices, and even more so NEMS devices, the standard constructs of classical physics are not always useful. Due at least to the large surface area to volume ratio surface effects, such as electrostatics and wetting, can dominate the volume effects such as inertia or thermal mass.
MEMS and NEMS can be fabricated using semiconductor device fabrication technologies normally used to make electronic devices. These include photolithographic patterning, sputtering, evaporation, and wet and dry etching.