July 2004

MEMS Blow past Air Bags

A new generation of micromachines could transform everything from eye surgery to cell-phone reception.

By Gregory T. Huang

A new generation of micromachines is coming to market. So far, commercial versions of tiny sensors and actuators built on silicon chips have performed simple tasks such as switching telecommunication signals on and off or triggering air bag deployment. The next wave of microelectromechanical systems-or MEMS-however, should bring devices that perform a broader range of tasks cheaply and efficiently. MEMX, a spinoff of Sandia National Laboratories in Albuquerque, NM, is commercializing advanced versions of the technology in products that could transform everything from eye surgery to cell-phone reception.

The key to these new applications is a sophisticated yet affordable fabrication process that stacks five layers of 2.5-micrometer-thick films onto chips with tremendous precision. The extra layers of tiny sensors, gears, and electronics-most commercial MEMS devices have only two or three layers-enable not only more complex machines but also more flexibility in product design. "It's utterly amazing what they can build," says Terry Turpin, chief scientist of Columbia, MD-based Essex, a leading optical-communications company. Says Turpin, who has worked on optics for 35 years, "It's the most sophisticated MEMS stuff I have ever seen."

That sophistication could soon go to work in your mobile phone. MEMX has developed tunable cell-phone components that sense signal fluctuations caused by changing weather conditions and distances to cellular towers and can automatically adjust a phone's circuits to compensate. That will mean fewer dropped calls, better sound quality, and longer battery life. MEMX is also building movable arrays of mirrors that will let patients preview the effects of certain eye surgeries by looking through an eyepiece. The arrays work by precisely filtering the light that interacts with the cornea on the basis of computer models of the surgery.

MEMX is working with various corporate partners to commercialize the products soon, says Paul McWhorter, the company's cofounder and chief technology officer. Expect to see cell phones with the tunable components on the market in 18 months and the first eye surgery simulators in two years. With the support of large investors like Agilent and recent grants from the U.S. government, MEMX is also working on farther-out products like micro surgical tools and implantable biodevices for automatic drug delivery.

Since 2000, the year MEMX was founded, a number of other MEMS companies that targeted specific industries, such as telecom, have folded. Now, wider-scale commercialization of microdevices promises to open new markets and allow the technology to "mature in the field," says Al Romig, a vice president and former chief technology officer at Sandia. That could put this new class of tiny machines to work in your life.