The "clean" referenced here isn't the white-glove kind of clean. It's
far to the extreme of that. The clean room is rated for two layers of
clean – one is Class 100, which means that it has no more than 100
particles measuring 500 nanometers or more in a cubic foot of air, and
the other is Class 1,000, which means it has no more than 1,000 such
particles per cubic foot.
For reference, an ordinary room would register about 100,000 particles per cubic foot.
To keep the air this clean, the air in the room is constantly pushed through filters, changing the air up to 300 times an hour.
Such hyper-clean conditions are mandatory because work at nanometer
length scales can be sabotaged by unwanted particles. Without such
measures, Xiao said, it would be like trying to frost a wedding cake
while someone is throwing basketballs at you.
The clean room has four separate bays for processes including
lithography, deposition of thin films, etching, and thermal processing.
Several doctoral candidates – including Xiangyu Ma, Jimmy Hack, and
Sarah Geiger – were at their nanofab stations Tuesday, properly suited
up with their clean-room gear.
"We're getting the tools up and running and they're helping us
qualify the tools," said Scott McCracken, facility specialist. "They're
starting to do some work as well, starting some of their own projects."
Ma, whose adviser is Doty, said his research includes development of
new semiconductors for future generations of computers. Hack has been
using a device called a magnetron sputterer to ionize particles, which
helps to deposit material onto silicon. And Geiger is working with
organic photoresist, which will be used in microfluidics and
"We're all really excited," Ma said.
The nanofabrication technology makes the University more appealing to
students and faculty with such interests, and George Watson, physicist
and dean of the College of Arts and Sciences, said he is taking the
opportunity to recruit new faculty.
"This is opening up new opportunities," he said.
Ira Winston, chief infrastructure officer at the University of
Pennsylvania's School of Engineering and Applied Science, saluted UD's
accomplishment and that of his former colleague, Iulian Codreanu, who is
now operations director of UDNF.
"We thought we built the premiere facility," Winston said. "But they
[UD] made some choices we didn't make. They have some things we don't.
So I know some of our users will be coming here. Collaboration is going
to happen. We have some things they don't and they have some things we