What are MEMS?
Microelectromechanical systems (MEMS) describes a category of devices and a technique for manufacturing them. MEMS devices are tiny machines with elements ranging from 1-100μ, or about the thickness of human hair. MEMS sensors gather information from the environment; MEMS actuators execute given commands, or act, generally through highly controlled movements.
MEMS devices are made using the basic fabrication techniques and materials of microelectronics. Thin layers of materials are deposited onto a base and then are selectively etched away, leaving a microscopic 3D structure. In this way, MEMS processes construct mechanical as well as electrical components. The electrical elements on the chip process data while mechanical elements act in response to that data. Integrated circuitry provides the thinking part of the system while the MEMS component complements this intelligence with active perception and control functions.
In some cases, MEMS has dramatically improved existing applications. Crash sensors for airbag safety systems are a good example. These are actually MEMS accelerometers that measure the force of an automobile crash and deploy an airbag if the force is great enough. Delivering improvements in functionality, compliance with safety standards, and a reduction in components over previous airbag safety systems, the accelerometer moves in response to the vehicle’s acceleration. Hinge- or spring-mounted to limit its movement, this inertial mass returns it to central position when at rest. Sensitive electrical sensors in the chip read the mass’s movement and relay data to a connected microprocessor, which monitors the state of acceleration at rest and in motion. In a collision, there is a sudden change in acceleration. When that change reaches an unsafe level, the airbags are deployed.
MEMS micro mirrors are another case-in-point. They use microscopic moving mirrors to improve image quality and reliability, and are almost like a light switch made up of millions of hinge-mounted mirrors. Each mirror measures about 1/5 the width of a human hair and corresponds to one pixel in a projected image. The micro mirrors are mounted on tiny hinges that allow them to tilt toward the light source to reflect the light or away from it to block the light. This creates a light or dark point on the projection surface. The length of the time the mirror faces the light determines the brightness of each pixel. In color systems, MEMS micro mirror-based projectors can create more than 16 million shades of color—high quality enough to replace traditional film projectors. Texas Instruments DLP, for example, is comprised of millions of MEMS micro mirrors.
MEMS are now ubiquitous.
- MEMS microphones are in smartphones, smart speakers, smart home systems, TV remotes, VR headwear and many other consumer, industrial, agricultural, automotive and other applications
- MEMS accelerometers are deployed in even larger numbers in such devices, in almost every electronic device imaginable; gyros are also shipping in the hundreds of millions
- Pressure sensors, environmental sensors and numerous other types of MEMS sensors are deployed widely as well
Why are MEMS important?
MEMS is an innovative technology that, in one embodiment, generates continued, sustained improvements in, for example, the functionality of small microphones, small cameras, and small electrical signal filters for wireless communication. In its other, disruptive, embodiment, MEMS technology creates entirely new kinds of products, such as inexpensive, multi-axis inertial motion sensors useful for smartphone-based navigation, and Digital Micromirror Devices (DMD), arrays of MEMS micromirrors used for high speed, efficient, and reliable spatial light modulation in industrial, medical, telecom, security, and other applications.
What is the History and Current State of MEMS?
The physicist Richard Feynman delivered a talk at Caltech in December 1959 with the title "There's Plenty of Room at the Bottom." “What I want to talk about,” said Feynman, “is the problem of manipulating and controlling things on a small scale.” The potential benefits of doing so? Creating “The marvelous biological system.” “Miniaturizing the computer.” Deploying “a hundred tiny hands” for a world in which we are “Rearranging the atoms.” In one sense, a real sense, Feynman laid the roots for today’s MEMS industry.
From those very early days and origins, MEMS has enjoyed classic hockey stick growth: i.e. a dramatic increases in sales revenue or unit shipment growth over time that started at a normal, linear pace from the 1960s through to the 1990s, hit an inflection point and took off in the 2000s, and sustained its considerable momentum into the 2010s, fueled by such MEMS-enabled killer apps as the Nintendo Wii, the Apple iPhone, Bosch airbag systems, Epson ink jet printheads, microphones from Knowles Electronics, and blood pressure sensors from Acuity, Merit Sensor, and others.
What is the Future of MEMS?
The future of MEMS is rich with commercial possibilities, including the trillions of MEMS sensors envisioned to be used as the eyes and ears of the Internet of Things (IoT); the future of MEMS also includes local MEMS-based environmental monitoring devices; deployments in the MEMS-enabled quantified self movement and in personalized medicine applications; MEMS-containing wearables; and MEMS-reliant drones and other small personal robots.
Why Choose MEMS?
The compelling reasons why thousands of OEMs have successfully chosen MEMS devices to create competitive advantages for themselves in both sustaining innovation and disruptive innovation business models include these: MEMS-based solutions yield product cost advantages for a given functionality; employing MEMS devices usually results in a reduced BOM for a given product, and the lower parts count for MEMS-based products enables a more efficient supply chain; the inherent compatibility of MEMS devices with CMOS electronics simplifies design cycles and speeds time-to-market; MEMS components typically demonstrate less power consumed per a given function than do other, macro-based solutions; and the fact that MEMS device and product reliability is as good as any reliability can be – MEMS devices can deliver military / automotive / medical device-class reliability in rugged, real-world applications.