National Academy of Engineering Honors Xin Zhang

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Xin Zhang and former graduate student Shusen "Forest" Huang inspect arrays of tiny infrared sensors.  Huang graduated in May 2007 with a Ph.D. in manufacturing engineering.
Xin Zhang and former graduate student Shusen "Forest" Huang inspect arrays of tiny infrared sensors. Huang graduated in May 2007 with a Ph.D. in manufacturing engineering.

The National Academy of Engineering selected Associate Professor Xin Zhang (MFG) to participate in the 13th annual US Frontiers of Engineering Symposium. Eighty-three engineers between the ages of 30 and 45 from across the country received invitations to the September meeting. The invitees, nominated by engineers or organizations and chosen from among more than 260 applicants, include representatives from industry, academia and government with research interests spanning a broad range of engineering and technical disciplines.

The NAE symposium gives a group of innovative, emerging leaders in engineering the opportunity to foster collaborations across disciplines by discussing several large scale engineering challenges. The 2007 meeting, scheduled for Sept. 24-26 at Microsoft’s Redmond, Washington campus, will address trustworthy computer systems, safe water technologies, modeling and simulating human behavior, biotechnology for fuels and chemicals, and the control of protein conformations.

“It’s interesting to go there. It’s important,” said Zhang. “You have a chance to interact and participate in discussions of important issues in science and engineering, and it’s very open — you have a chance to speak with people from government labs, industry and academics.” She hopes to contribute to the discussion on biotechnology for fuels and chemicals, in particular.

Zhang came to the College of Engineering in 2002 from MIT where she was a research scientist in the Microsystems Technologies Laboratory and Gas Turbine Laboratory. Her research in manufacturing engineering at BU encompasses work on biological, photonic and power applications of micro-electro mechanical systems (MEMS) as well as development of new manufacturing technologies and materials for MEMS and NEMS.

Zhang’s lab currently includes one visiting scholar, nine graduate students and four undergraduate researchers. Zhang and her team receive funding from the National Science Foundation, the Air Force Office of Scientific Research, the Army Research Laboratory, National Institute of Health and other organizations to work on a variety of projects in NEMS and MEMS research.  Recently, she won an NSF grant to study MEMS materials and published an article on one of her research interests, improving heat sensing technology.

With a three-year $150,000 grant from the Civil, Mechanical and Manufacturing Innovation (CMMI) division of the NSF, Zhang will study new MEMS materials.

Researchers today are more commonly adopting new amorphous thin films as building materials to build these millimeter-scale devices. The new materials hold promise for improving the fabrication of MEMS and the function of the devices beyond that of crystalline thin films, which until now have seen much more use in MEMS and semiconductor industries.

Knowing when and how to best use the amorphous thin films remains somewhat of a guessing game for researchers, though. Zhang will study how conditions such as heat or stress affect these materials’ mechanical properties, using one such material, plasma enhanced chemical vapor deposited silicon oxide thin film, as a case study. Understanding the reliability and characteristics of this material will help the MEMS industry best use these new materials.

“It’s really a unique integration between the pure research and applied science of MEMS technologies,” said Zhang.

Zhang also recently published research in the July issue of the Journal of Micromechanics and Microengineering that could lead to improvements in cantilever structures used in heat sensing. These infrared sensors are used in firefighting and military technology, medical equipment and for diagnosing structural weaknesses in buildings.

The devices’ heat sensing ability depends on arrays of tiny cantilevers. The degree of cantilever bending correlates to changes in heat. But the delicate cantilevers, each just 50 micrometers by 50 micrometers, can pre-bend during manufacture when they are layered just a half a micrometer apart from each other, ruining the sensitivity and usability of the final product.

Zhang’s research into the stresses that cause this premature bending may lead to improvements in cantilever manufacture, making the next generation of infrared sensing technologies more durable and more sensitive than those available today.

Xin Zhang's team uses this Cascade probe station to characterize MEMS structures and devices.
Xin Zhang's team uses this Cascade probe station to characterize MEMS structures and devices.