Micro-electro-mechanical systems (MEMS) are microscopic structures fabricated by etching away tiny amounts of silicon using similar processes as are used to make computer chips. These small electronic and mechanical structures are already being used in a number of commercial applications such as, for example, the sensors used to deploy airbags in an automobile crash.
But the use of MEMS in sensing applications goes much farther than that. At Virginia Tech, two different research groups are applying these techniques to create tiny, ultrasensitive devices to detect chemical and biological materials for medical, environmental and security applications.
Dr. Masoud Agah, under an NSF Career grant, has been working on developing many MEMS devices in his MicrON research group. The current research at VT MEMS Lab centers on the development of CMOS-compatible three-dimensional silicon micromachining techniques, smart microchip coolers, micro gas analyzers for environmental and healthcare applications, and biochips for cancer diagnosis and cancer treatment monitoring. In addition, the lab is pursuing research to merge MEMS (top-down approach) and nanotechnology (bottom-up approach) in order to enhance the performance of the microsystems.
In the Center for Photonics Technology (CPT), Dr. Anbo Wang‘s group is using the same fabrication techniques to create tiny sensors on the tip of an optical fiber only a couple of microns in diameter. In one of CPT’s latest inventions, the MEMS structure is used to detect trace amounts of chemical and biological materials, as well as serving as a tunable optical filter. The new device is activated using only light traveling inside the fiber, and so requires no external electrical or mechanical energy, making it perfect for applications in hazardous or remote environments.
Both of these MEMS technologies create the opportunity to improve detection of trace materials, and will be important in medical and environmental sensing applications, including those relating to security.