microelectromechanical

Microelectromechanical systems (MEMS) are devices that integrate mechanical elements, sensors, actuators, and electronics on a common substrate, typically silicon, at micrometer-scale dimensions. MEMS combine electrical and mechanical functionality to sense, control, and manipulate small forces and motions.

Fabrication relies on microfabrication techniques derived from the semiconductor industry. Processes such as photolithography, etching (bulk and surface), and thin-film deposition create movable structures like cantilevers, bridges, gears, mirrors, and resonators. Materials commonly used include doped silicon, silicon nitride, silicon carbide, glass, and various polymers. Devices are often encapsulated to protect delicate moving parts and to control the operating environment.

MEMS devices embed sensing and actuation functionalities. Sensors convert physical quantities such as acceleration, pressure, temperature, magnetic fields, or chemical presence into electrical signals; actuators induce motion, tilt mirrors, drive micropumps, or operate microvalves. The tight integration of sensing, processing, and actuation enables compact, low-power systems with high functionality.

Applications span numerous sectors. In consumer electronics, MEMS accelerometers and gyroscopes enable motion sensing in smartphones, tablets, and wearables. Automotive uses include airbag deployment sensors and tire-pressure monitoring. Medical and biology fields employ MEMS for lab-on-a-chip diagnostics and implantable sensors. Optical devices use MEMS mirrors in displays and projectors, while RF MEMS are explored for communications.

Manufacturing and integration often couple MEMS with CMOS electronics on the same wafer or in stacked packages, with packaging playing a critical role for reliability. Challenges include packaging complexity, reliability under varying environments, stiction, wear, and cost, but the technology continues to enable smaller, cheaper, and more capable sensing and actuation solutions.