Microelectromechanical systems, commonly known as MEMS, are miniature devices that integrate mechanical and electrical components on a microchip. Though MEMS devices are measured on the microscale and even nanoscale, they are having an enormous impact across multiple industries by bringing together silicon-based microelectronics with microfabrication technology.
What are MEMS?
MEMS refer to devices that combine electrical and mechanical components and are measured in micrometers. At its simplest, a MEMS device integrates a mechanical element, sensor, actuator and controller on a common silicon substrate using microfabrication technology. The components are fabricated using techniques from integrated circuit (IC) manufacturing such as sputtering, etching, deposition and lithography. This allows the integration and co-fabrication of mechanical, electrical and fluidic components in devices that can sense, control and actuate on the micro-scale.
Applications of MEMS
MEMS have enabled the miniaturization of devices and systems across a wide range of applications. Some key areas where MEMS devices are making an impact include:
Automotive: MEMS sensors are now commonly used in automobiles for airbag deployment, drive-by-wire systems, engine management systems, navigation and stability control. MEMS pressure sensors, accelerometers and gyroscopes provide critical sensor data for advanced driver-assistance systems.
Consumer Electronics: Microelectromechanical systems accelerometers in smartphones and tablets allow touchscreens to sense orientation changes. MEMS gyroscopes and accelerometers enable motion tracking and augmented reality features. MEMS microphones are replacing traditional microphone designs.
Medical: MEMS pressure sensors, temperature sensors, glucose sensors, flow sensors and nebulizers are used in medical equipment, healthcare monitoring, drug delivery and lab-on-a-chip diagnostics. MEMS endoscopes provide minimally invasive surgery options.
Industrial: MEMS pressure sensors, gyroscopes, inertial measurement units (IMUs), temperature sensors and accelerometers enable condition monitoring, predictive maintenance, automation and process control across industries like oil & gas, manufacturing, energy and more.
Aerospace: MEMS gyroscopes provide precision navigation, guidance and control capabilities for aerospace applications like unmanned aerial vehicles, satellites, rockets and more. MEMS accelerometers enhance safety features.
How are MEMS Made?
MEMS Fabrication relies on the well-established techniques used in integrated circuit (IC) manufacturing like deposition, lithography, etching and bonding:
– Deposition: Materials like silicon, polymers and metals are deposited on a substrate using processes like sputtering and chemical vapor deposition to create thin films.
– Lithography: Photosensitive chemicals like photoresist are patterned on the deposited thin films using photolithography, which involves exposing the photoresist to light through a photomask to define patterns.
– Etching: Exposed or unexposed regions of the photoresist are selectively removed by wet or dry etching to transfer the pattern from the photomask to the underlying thin film material layer.
– Bonding: Additional wafers or device layers are bonded, often using anodic or fusion bonding, to add mechanical structures and form enclosed cavities.
– Doping: Ions are implanted into the silicon using a process called doping to add functionality by controlling conductivity.
– Release: Final release etching frees the movable mechanical structures.
All these steps are repeated to build up the multilayered structures which enables both electrical and mechanical parts to be fabricated together on the same silicon chip. Computer-controlled etching and deposition allows complex 3D structures at micro and nanoscales.
Future Growth of MEMS
According to industry analysts, the global MEMS market size is expected to continue its robust growth reaching over $86.3 billion by 2026, registering a compound annual growth rate (CAGR) of 10.4% during the forecast period.
Some factors driving the growing demand and market growth of MEMS include:
– Miniaturization of devices across consumer electronics, wearables, medical implants and more will push development of smaller MEMS components.
– Adoption of MEMS in newer domains like augmented reality, virtual reality, autonomous vehicles, drones, 3D printing and Internet of Things will open huge avenues.
– Advancements in fabrication like nanoimprint lithography, directed self-assembly, 3D multilayer fabrication processes will enhance MEMS capabilities.
– Material innovation in substrates, thin films, polymers and hybrid integration of MEMS with flexible, stretchable and biocompatible materials will expand applications.
– Improvements in MEMS reliability, lifetime, hermetic sealing and packaging technologies are needed for some industries like automotive and harsh environments.
The combination of microsystems technology and electronics has enabled the miniaturization of systems and enabled capabilities unimaginable few decades ago. MEMS technology has revolutionized sensing, actuation, information processing and control at micro and nano scales. With constant innovation driving further miniaturization across industries, MEMS will continue powering the development of life-changing microsystems and ubiquitous sensing networks of tomorrow.