Dr. Ming Zhang isn’t interested in the big picture. Zhang, operator of the only focused ion beam microscope in Missouri, is much more curious about things you can’t see with your own eyes.
Missouri University of Science and Technology recently hired Zhang to operate its focused ion beam (FIB) scanning electron microscope. The piece of equipment, which cost more than $1 million dollars, was purchased in 2008 with funds made available by the National Science Foundation and the U.S. Air Force Research Laboratory.
In addition to its magnification powers, the FIB machine allows researchers to modify the samples being analyzed. The multi-purpose machine has an electron microscope that magnifies objects up to a million times and a focused ion beam that can be used to bombard and remove atoms. The ion beam is what makes it possible to make impressions on a silicon wafer, for instance.
FIB technology has typically been used in Silicon Valley for computer chip repair and electronic circuit modifications. “If one transistor out of millions goes bad on a chip, the FIB is the best way to see what happened,” says Zhang, whose official title is senior research scientist at Missouri S&T’s Materials Research Center.
Once a problem has been identified, scientists like Zhang can practice a sort of nano-surgery by making a focused cut into a bad transistor and then performing a welding operation.
Zhang practiced this craft while at Northwestern University, which had FIB technology before Missouri S&T. After S&T got its machine last year, Zhang was hired specifically to help the campus utilize it.
The FIB machine will be used to assist with various research projects across campus. S&T researchers intend to employ the versatile instrument to study nano-scale changes in metals that have been stressed, ancient bacteria that are trapped in salt crystals, and the behaviors of special coatings used to paint aircraft.
The Air Force is currently using a non-chrome coating developed at S&T in the re-painting of F-15s. The chrome-free coating reduces health risks for workers who apply primer to military aircraft.
“The FIB is the best way to get a cross-section at site-specific positions to see how the coatings really work and behave,” says Zhang.
Missouri S&T departments may purchase time on the machine (under Zhang’s supervision) for a highly discounted hourly rate. But companies also send Zhang chips and other materials to study. Because S&T is the only university in Missouri with this type of equipment, it is able to charge companies a much higher – but still competitive – hourly rate for FIB analysis.
Before Zhang was hired, Dr. F. Scott Miller was one of the first S&T researchers to learn how to operate the machine. “One of the biggest advantages is that we’re used to looking at only the outer surfaces of materials,” says Miller, associate professor of materials science and engineering. “We now have the ability to look deeper and deeper into a sample. It’s like peeling the layers of an onion.”
Soon, Miller realized that he could also use the instrument to manipulate a sample. Not long after the new FIB machine had arrived in Rolla, Miller illustrated its capabilities to the rest of the campus by reproducing Missouri S&T’s logo near the eye of a sewing needle. Using the machine’s focused ion beam, Miller was able to etch a microscopic replica of the logo into the needle’s surface.