Structural Miniature
Integrated circuit fabrication techniques produce tiny mechanical structures alongside electronic circuits on a single silicon substrate. Micro-electro-mechanical systems include moving parts like beams, gears, and diaphragms that respond to physical stimuli. These devices occupy a volume measured in cubic millimeters.
Sensing Principle
Capacitive or piezoresistive changes in the internal structure translate motion into an electrical signal. In an accelerometer, the micro-electro-mechanical systems architecture uses a proof mass suspended by silicon springs. When the mass moves, the distance between the sensing electrodes changes the measured capacitance.
Manufacturing Sequence
Bulk micromachining and surface deposition create the layered features through a series of lithographic masks. Etching processes remove sacrificial layers to release the moving parts. Because micro-electro-mechanical systems are made using semiconductor equipment, they can be produced in high volumes at low unit costs.
This scalability led to their adoption in consumer electronics for screen rotation and image stabilization. The integration of the sensor and the amplifier on one chip reduces the noise interference from external wires.
Package Constraint
Hermetic sealing is required to protect the delicate mechanical parts from moisture and dust. Vacuum packaging or gas filling controls the damping of the moving structures. The micro-electro-mechanical systems housing often includes a lid with a specific cavity depth to allow the internal mass to move freely.
