University of North Texas Resource Magazine: Advanced Research

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UNT Resource magazine >> Advanced Research

The University of North Texas has taken a big step into the tiny realm of nanotechnology — the engineering of materials at atomic and molecular levels. With the opening this year of the new Laboratory for Electronic Materials and Devices, UNT becomes a major player in the increasingly important area of electronic materials.
    The 2,300-square-foot laboratory — located in the basement of the Engineering Technology Building — will support both basic and applied research on new materials used in electronic devices of all kinds. The U.S. Department of Commerce has identified advanced materials as one of five emerging technologies the United States must master to remain competitive in the world marketplace.
    The laboratory was conceived as a cross-disciplinary research center engaging faculty and students from the chemistry, physics, biological sciences and engineering technology departments, as well as UNT's materials science department.
    The core of the new laboratory's instrumentation was donated to UNT by Texas Instruments. Although the research equipment was associated with three separate laboratories at TI, faculty members in the UNT Department of Materials Science saw the potential value of combining the three components into a single comprehensive research tool that would enable them to create new materials for use in a wide range of advanced electronic applications.
    The result is a laboratory with capabilities unique among academic materials science laboratories in the United States and available in only a few such laboratories in the world.
    "This lab represents an important expansion in the sciences at UNT," says Bruce Gnade, professor and chair of the Department of Materials Science. The creation of the laboratory, he says, provides a boost to the materials science program and to the university's growing reputation as a research center.

Atom by atom
The initial research programs in the new lab will focus on the field of advanced dielectric (insulating) materials. These materials, made up of compounds of silicon, germanium or a combination of the two, are considered essential to progress in the continuing miniaturization of integrated circuits. Research at the lab will focus on the physics and chemistry of advanced electronic materials required for microprocessors used in computers, telecommunications and electronically based information systems of the future.
    "This is the area of research with the highest activity," says Robert M. Wallace, director of the laboratory and professor of materials science. "It's where industry is putting most of its materials research money, and it's the area in which industry expects the most results from the research community."
    One of the unique characteristics of the laboratory is that the three principal components — the Molecular Beam Epitaxy System, the Surface Science System and the Ion Beam Accelerator System — are coupled to provide a continuous vacuum in which to transport samples.
    "The idea is to be able to grow a film on a silicon wafer, move it throughout the systems and analyze it without ever taking it out and exposing it to the air," explains Wallace. A film is a very thin layer of material — a tiny fraction of the thickness of a human hair.
    Because each operation is performed in an ultrahigh vacuum environment, an electronic device or component may be synthesized, modified and characterized in a continuous process.
    "If the film is exposed to the air," he says, "it becomes contaminated. It's no longer what we intended it to be."
    The vacuum in the system is 10-10 Torr, which corresponds to the vacuum in space at an altitude of about 30 miles above the Earth's surface.
    "We'll be able to 'grow' materials one layer of atoms at a time," says Gnade. "The actual materials may be no more than 10 atomic layers thick. We want to control the process at the atomic level. Making devices smaller and building them atom by atom — that's what this system is designed to do."
    And, says Wallace, the research team will be trying to understand how these films grow and how to control their growth in a reproducible way.

Lab components
It's in the MBE System that the thin films will be deposited on a silicon or germanium wafer. Three independent deposition chambers are connected by a transport system that allows the wafer to move through the process in a continuous vacuum. The three different chambers are used to deposit semiconductors, metals and dielectrics. The MBE is coupled to the Ion Beam Accelerator System and the Surface Science System, both of which are used to evaluate the structures created in the MBE System.
    The second component — the Surface Science System — will analyze, or "characterize," the surface of materials chemically and physically to determine their suitability for electronic applications. Examining the materials using X-ray photoelectron, Auger electron and ultraviolet photoelectron spectroscopies, the SSS will dissect the surface atom by atom.
    The 20-foot-long, seven-ton Ion Beam Accelerator System is a particle accelerator that can analyze the atomic makeup of electronic materials by bombarding them with a particle beam, then detecting the resulting scattered particles, X-rays and events that are characteristic of each particular element.
    An instrument known as a Variable Temperature Scanning Tunneling Microscope, located in the laboratory on a specially designed vibration-isolation floor, will also be used to analyze materials. It has a spatial resolution of better than one atom at temperatures approaching absolute zero.

Future research
Construction of the laboratory got under way in the late summer of 1999 and was completed by April of this year. The lab's research apparatus is being commissioned in stages, Wallace says. The Surface Science System was already taking data in July. The MBE went online in the fall, and the Ion Beam Accelerator System should be up and running by the end of the year.
    Both Gnade and Wallace worked with the equipment at TI before they came to UNT.
    "The lab was designed from our experience of how an industrial laboratory works," Wallace explains.
    He says that design of the lab infrastructure allows for changes in research direction.
    "As our funding changes, as we change research interests, we can add or decommission equipment and keep right on going."
    Wallace and Gnade have secured approximately $2 million in research funding from an array of federal, state and industry sources. The university has invested $700,000 for construction of the lab, and the contribution from Texas Instruments in excess of $3 million includes the apparatus as well as supplies, spare parts and a portion of the lab's infrastructure.
    The laboratory will also be involved in at least two more areas of research in the near future. Researchers will study devices based on field emission arrays, which have a variety of potential applications including high-power amplifiers, spacecraft propulsion for very long missions, improved flat-panel displays for televisions and computer screens, and decontamination of air contaminated by chemical or biological warfare agents. A key area of research for these devices is improving the basic understanding of long-term reliability and stability of performance over time.
    The other initiative involves molecular electronic devices, which use biological principles to construct electronic circuits. Researchers will explore the possibility of using single molecules or assemblies of molecules to perform traditional electronic functions.
    Industrial researchers, Wallace points out, don't always have the time to determine why processes in the field of materials science work as they do.
    "That's why they're interested in funding academic research," he says. "That's the missing link. That's the kind of problem that fits in a university environment."

Partners in research

UNT's new Laboratory for Electronic Materials and Devices owes its existence to a major donation by Texas Instruments. The Dallas-based company reorganized its internal research and development effort in 1998, and the apparatus that it no longer needed is now the core of the new UNT facility.
      Valued at $3.5 million, it's part of a total package of $6 million of equipment designated by TI for member institutions of the Metroplex Research Consortium for Electronic Devices and Materials. The organization, which includes UNT as well as Southern Methodist University, Texas Christian University and the University of Texas at Arlington, was formed to advance the study of electronic devices and materials at member schools. An estimated 4,500 students at the four universities are majoring in areas relevant to the aims of the consortium.
      "The gift shows confidence in the university and in the research we'll be able to do," says Bruce Gnade, professor and chair of the UNT Department of Materials Science. Such confidence, he says, can only enhance the university's reputation in the field of materials science. This, in turn, could lead to broader interest in UNT's program by other leaders in the industry.
      It's a gift that will keep on giving to the donor as well as to the recipient. Robert Wallace, professor of materials science and director of the new laboratory, points out that the research conducted there "will be in the electronic world where TI does business."
      Also, the proximity of UNT to TI headquarters means greater interaction and exchange between university researchers and the company.
      "It's much easier for TI to collaborate with a local university laboratory than with a university far removed," Wallace says.
      But perhaps the greatest benefit to TI will be the UNT graduates, whom Wallace calls "an educated work force tailored to TI's needs." Again, because of the closeness of the two institutions, TI can recruit new employees right in its own backyard, he says.
      Wallace's observations echo the sentiments of Thomas J. Engibous, TI chair, president and CEO. "This donation will provide needed tools to the local universities for long-term research in areas that are important to TI's future," he said when the company announced the gift in October 1998. "There are clear benefits to Texas Instruments of having strong university research programs in the region. They are valuable partners in joint research developments with TI and enhance our ability to recruit the top technical graduates."
      Obviously, the ability of UNT graduates to secure good jobs will also be enhanced, says Rollie Schafer, UNT's vice provost for research and professor of biological sciences. "Thanks to TI, undergraduate and graduate students at UNT will benefit from direct participation in cutting-edge research and interactions with industry," he says. The result will be an annual group of graduates in high demand in the high-tech world.