What’s a MEMS device?

The machines you see around you everyday are composed of two integrated components, mechanical and electrical, that work together to accomplish a desired task. But did you know that these machines have been improved over the years with the inclusion of even smaller machines, so small you can’t even see with your naked eye?

These tiny machines are called MEMS devices. MEMS stands for micro-electromechanical systems because they:

• Are very tiny: their components are between 0.001 to 0.1mm in size, and the total system is usually 0.02 to 1mm in size
• Involve electrical and mechanical components, albeit on a much simpler scale than the machines seen around us: the electrical part relays or receives an electrical signal to non-MEMS devices, while the mechanical part senses a specific parameter (ex. temperature or force) or makes a specific motion (ex. actuating a tiny piece in the system).

MEMS devices from Sandia National Laboratories

The machines you see every day are typically built using manufacturing techniques you may be familiar with, like drilling, milling, turning, etc. But these techniques are nowhere near precise enough to make these MEMS devices, so they’re made instead via electrochemical processes similar to those used to fabricate IC chips, such as guided etching, in specialized clean rooms that remove any particles that could damage these tiny systems.

You can find MEMS devices in a lot of the technology you use everyday. For example, have you ever wondered how your car knows to fire the air bag or not? A MEMS accelerometer can detect large changes in velocity in the milliseconds required to save the passengers’ life. Ever wonder how your screen automatically rotates accordingly as you rotate your phone? That’s due to the phone’s MEMS gyroscope! Check out this teardown to see the MEMS gyroscope in the iPhone 4.

The iPhone 4 gyroscope: a MEMS device! (iFixit)

Check out more applications of MEMS here!