The micro mechanical device embedded with electronics/electrical system fabricated through a mix of integrated circuit manufacturing and micro-machining process where material is shaped by etching away micro layers is called Micro Electro Mechanical System (MEMS). The intelligent electronic system part is integrated in the same way of IC device fabrication. The most popular material used for MEMS is Silicon for it's semiconductor , physical and commercial properties.
Micro-Electro-Mechanical Systems consists of mechanical elements, sensors, actuators, and electrical and electronics devices on a common silicon substrate.
The sensors in MEMS gather information from the environment through measuring mechanical, thermal, biological, chemical, optical, and magnetic phenomena. The electronics then process the information derived from the sensors and through some decision making capability direct the actuators to respond by moving, positioning, regulating, pumping, and filtering, thereby controlling the environment for some desired outcome or purpose. The advantages of semiconductor IC manufacturing such as low cost mass production, reliability are also integral to MEMS devices.
The size of MEMS sub-components is in the range of 1 to 100 micrometers and the size of MEMS device itself measure in the range of 20 micrometers to a millimeter.
Some of the advantages of MEMS devices are,
1. Very small size, mass, volume
2. Very low power consumption
3. Low cost
4. Easy to integrate into systems or modify
5. Small thermal constant
6. Can be highly resistant to vibration, shock and radiation
7. Batch fabricated in large arrays
8. Improved thermal expansion tolerance
There are plenty of applications for MEMS. As a breakthrough technology, MEMS is building synergy between previously unrelated fields such as biology and microelectronics, many new MEMS and Nanotechnology applications will emerge, expanding beyond that which is currently identified or known.
MEMS technology finds applications in the below general domains
1. Airbag Systems
2. Vehicle Security Systems
3. Intertial Brake Lights
4. Headlight Leveling
5. Rollover Detection
6. Automatic Door Locks
7. Active Suspension
2. Sports Training Devices
3. Computer Peripherals
4. Car and Personal Navigation Devices
5. Active Subwoofers
1. Earthquake Detection and Gas Shutoff
2. Machine Health
3. Shock and Tilt Sensing
3. Equipment for Soldiers
1. Polymerase Chain Reaction (PCR) microsystems for DNA amplification and identification
2. Micromachined Scanning Tunneling Microscopes (STMs)
3. Biochips for detection of hazardous chemical and biological agents
4. Microsystems for high-throughput drug screening and selection
5. Bio-MEMS in medical and health related technologies from Lab-On-Chip to biosensor & chemosensor.
The commercial applications include:
1. Inkjet printers, which use piezo-electrics or thermal bubble ejection to deposit ink on paper.
2. Accelerometers in modern cars for a large number of purposes including airbag deployment in collisions.
3. Accelerometers in consumer electronics devices such as game controllers, personal media players / cell phones and a number of Digital Cameras.
4. In PCs to park the hard disk head when free-fall is detected, to prevent damage and data loss.
5. MEMS gyroscopes used in modern cars and other applications to detect yaw; e.g. to deploy a roll over bar or trigger dynamic stability control.
6. Silicon pressure sensors e.g. car tire pressure sensors, and disposable blood pressure sensors.
7. Displays e.g. the DMD chip in a projector based on DLP technology has on its surface several hundred thousand micromirrors.
8. Optical switching technology, which is, used for switching technology and alignment for data communications.
9. Interferometric modulator display (IMOD) applications in consumer electronics (primarily displays for mobile devices).
10. Improved performance from inductors and capacitors due the advent of the RF-MEMS technology
Few examples of real MEMS products are,
1. Adaptive Optics for Ophthalmic Applications
2. Optical Cross Connects
3. Air Bag Accelerometers
4. Pressure Sensors
5. Mirror Arrays for Televisions and Displays
6. High Performance Steerable Micromirrors
7. RF MEMS Devices
8. Disposable Medical Devices
9. High Force, High Displacement Electrostatic Actuators
10. MEMS Devices for Secure Communications
MEMS devices used in Space exploration field include:
1. Accelerometers and gyroscopes for inertial navigation
2. Pressure sensors
3. RF switches and tunable filters for communication
4. Tunable mirror arrays for adaptive optics
5. Micro-power sources and turbines
6. Propulsion and attitude control
7. Bio-reactors and Bio-sensors, Microfluidics
8. Thermal control
9. Atomic clocks