Jul 12 2016
Academic and industrial researchers have begun working side-by-side at the University of Chicago’s Pritzker Nanofabrication Facility, using some of the world’s most advanced tools to exploit the atomic and molecular properties of matter for emerging applications in science and technology.
The largest sources of contamination in a cleanroom are the occupants themselves. To protect the integrity of the cleanroom, users don special gear to contain the particles that they continually emit. (Credit: Robert Kozloff/University of Chicago)
“You can’t really do engineering systems from the molecular level up like we’re aiming to do without something like the Pritzker Nanofabrication Facility,” says Matthew Tirrell, dean and Pritzker Director of the Institute for Molecular Engineering.
Since the facility opened in February, its biggest users have been UChicago students in molecular engineering, physics, and chemistry working on their own projects and in collaboration with faculty members. There are also users from other university campuses as well as industry.
“We have students working on a variety of different projects, including making devices for applications in quantum information, working on devices that use microfluidic technology, and developing detectors for astrophysical applications,” says Andrew Cleland, the John A. McClean Sr. Professor of Molecular Engineering Innovation and Enterprise and faculty director of the Pritzker facility.
Microfluidic devices can be used to detect and measure the properties of single cells, viruses, or other biological components. In the astrophysical realm, researchers fabricate sensors for the South Pole Telescope to detect the cosmic microwave background radiation, the afterglow of the Big Bang.
The facility’s tools offer the capability of manufacturing devices ranging in size from a few inches down to 10 nanometers—a size that compares to the width of a human hair as the width of that hair does to the height of a human.
“Being able to craft objects on the nanometer scale with state-of-the-art equipment is going to enable extraordinary experiments on the campus,” says David Awschalom, the Liew Family Professor in Molecular Engineering and IME’s deputy director for space, infrastructure, and facilities.
Large nanofacility
Support for the 10,000-square-foot facility in the William Eckhardt Research Center came partly from a $15 million gift from the Pritzker Foundation. The National Science Foundation provided an additional $5 million to establish the Soft and Hybrid Nanotechnology Experimental Resource, a partnership between UChicago and Northwestern University. The NSF grant provides funding for support staff and training for external industrial and academic users who seek to develop nanostructure fabrication capabilities at the Pritzker facility and at Northwestern.
“Today’s clean room is the machine shop of our time,” says Awschalom. “A generation ago it was all about state-of-the-art mills, lathes, making very tiny structures with wire-cutting tools. Today it’s the nanofabrication facility and advanced etching techniques.”
But launching new technological products requires the involvement of industry, he notes.
“Universities are fantastic at generating creative concepts and ideas and developing proof-of-concept prototypes. To transition these ideas into society, it will be vital to engage the expertise of startup companies and industry.”
Facility users will complete training before using the cleanroom. They will pay an hourly fee for access, and may pay additional fees for the use of specific tools and equipment. The proceeds go to support the facility’s operations.
“Our plans are that this facility will eventually be open 24/7, meaning that it will have access for graduate students as well as external users any time of the day or night,” Cleland says. “Industrial users will be an important part of our user base, and they will also tie in our graduate students to the industrial efforts that are related to their research.”
Ultra-clean bays
As an ISO Class 5 cleanroom, the Pritzker facility contains air with 100 or fewer particles measuring five microns (one tenth the width of a human hair) or larger per cubic foot. Outside air typically contains more than a million dust particles of this size per cubic foot.
The facility sports a bay-and-chase design, with six bays (ultra-clean work spaces) alternating with chases (return-air spaces).
“One positive impact of our gift from the Pritzker Foundation was our ability to purchase new equipment for the facility,” says Sally Wolcott, the facility’s business manager. “This allowed the PNF to design and plan tool purchases such that bay one is completely empty, giving us room for expansion. We have money already earmarked, and we will continue to acquire tools based on need.”
The chases serve as giant vacuum cleaners, recirculating the air through nearly 1,000 filters to keep the facility clean. People working in the facility also must wear a special coverall, a hairnet, gloves, and covers for mouth and shoes.
“In its simplest terms, the Pritzker facility is used for three primary activities,” said Peter Duda, its technical director. “We add materials, we remove materials, and we use different techniques to create patterns in those materials. By layering all of those patterned materials that you’ve added and subtracted, you can create devices.”
The work is extremely precise. With the facility’s atomic-layer deposition tools, researchers can deposit a film one atomic layer at a time. One such material that can be grown this way is aluminum oxide, “a ceramic very similar to what your coffee cup is made of,” Duda says. But as an electrical insulator it is used in integrated circuits and in superconducting devices.
Superconducting devices are among the interests of David Schuster, assistant professor in physics and an IME fellow. Schuster plans to install his multi-angle electron-beam evaporation system in the Pritzker facility.
“It supports the evaporation of superconducting metals such as aluminum, niobium, and tantalum on wafers up to four inches in diameter,” Schuster says. The system can create high-quality superconducting Josephson junctions, which are a key element in superconducting circuits.
Schuster’s collaboration with Awschalom and Cleland signals more synergy to come between IME and other departments.
“Working with the Awschalom and Cleland groups has been wonderful, making UChicago one of the premier destinations in the world for quantum physics,” Schuster says.