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Computerworld - DEFINITION: MicroElectroMechanical Systems (MEMS) technology enables the creation of tiny machines that can work with microelectronics. MEMS also refers to the machines themselves, which add very small sensors and actuators that allow microchip-controlled systems to sense and control their environments.

“The very rich are different from you and me,” wrote F. Scott Fitzgerald. Similarly, very small things operate under different constraints than the machines and tools we’re accustomed to seeing and using in everyday life.

In the microscopic world, the standard principles of classical physics don’t always hold true. Factors such as weight, inertia and thermal mass become less important, while forces related to surface area, including friction and surface tension, take on much greater significance. Think about how an ant is able to carry something many times its own weight or a water bug can skate across the surface of a pond. It’s a different world down there.

We humans can take advantage of these differences through MEMS, in which tiny, sometimes microscopic mechanical elements are created on silicon chips using fabrication technologies similar to those used for making integrated circuits.

MEMS — also referred to as micromechanics or micromachines — can refer to both the technology and the specific devices, which range from a micrometer to a millimeter in size. Smaller devices are called NanoElectroMechanical Systems (NEMS) or simply nanotechnology. MEMS and NEMS operate using the principles of mechanics in tiny versions of the classical simple machines (inclined plane, wheel and axle, lever, pulley and screw). Today, MEMS refers to almost any miniaturized device, regardless of whether it’s based on silicon technology or traditional precision engineering.

Why Go Small?

Just as birds can fly but elephants can’t, MEMS devices can easily do things that are problematic for larger ones. For example, sensors and actuators are the most costly and least reliable parts of many human-scale machines and control systems. Large devices can’t move as quickly or as precisely as microscale machines; precision in large machines is expensive and often difficult to mass-produce.

In contrast, MEMS technology allows us to create complex electromechanical systems that can move, position, regulate, pump and filter, and to manufacture them in quantity using batch fabrication techniques originally developed for the semiconductor industry. This puts the cost and reliability of such small sensors and actuators on a par with those of electronic integrated circuits, enabling superior performance at much lower cost.

How to Make MEMS

MEMS are typically made on a silicon substrate using some of the same microfabrication technologies (indeed, sometimes the same machinery) designed to produce microprocessors and other electronic integrated circuits.