Vanderbilt University Register: NSF recognizes chemical engineer

by Vivian Cooper-Capps

Rogers

Bridget R. Rogers, assistant professor of chemical engineering at Vanderbilt University, has won the prestigious Career Award from the National Science Foundation for her research on alternative materials that could be used to make faster and more economical computer components.

The Faculty Early Career Development awards are considered NSF's most prestigious honor for junior faulty members. They range in amount from $200,000 to $500,000 and in duration from four to five years.

The national award, given to selected faculty for their exceptionally promising research, will enable Rogers and her associates to study thin films made of alloys that could replace the silicon dioxide currently used in transistors and other microelectronic devices that are the heart of computers and telecommunications devices.

The computer industry is searching for materials to replace silicon dioxide because it will not function properly as computer components continue to shrink in size.

"The semiconductor industry is well aware that it is rapidly approaching the functional limits of silicon dioxide used in computer transistors," Rogers said. "Successful replacement of silicon dioxide is a critical step in the continued drive to build faster, lower-power, more integrated circuits."

A layer of silicon dioxide is used to make the part of a computer transistor within an integrated circuit that plays the pivotal role in switching the transistor on or off. As the transistor is reduced in size, the silicon dioxide layer must also be reduced in thickness, ultimately becoming too thin to function adequately to control the transistor's electrical current.

Rogers and her multidisciplinary team are studying certain thin films made of alloys strong enough at the molecular level to replace silicon dioxide as transistors are made smaller.

To study these extremely thin films, Rogers designed a unique ultra-high-vacuum chemical vapor deposition reactor that deposits the alloy and allows the researchers to study their properties before they are exposed contaminants in the air.

Rogers and her associates will use an instrument called a spectroscopic ellipsometer, recently purchased through a grant from the U.S. Defense University Research Instrumentation Program, to study alloy films of aluminum oxide and zirconium oxide. The laser equipment will be installed in the reactor and will allow the researchers to analyze the materials in place by studying their response to varying wavelengths and angles of laser light.

The films will also be analyzed in three other Vanderbilt laboratories to determine their electrical, chemical and physical properties.

"What we're looking for is an alloy that can deliver the strong insulating qualities required," Rogers said. "Because the probability is low that a material system can meet all the required criteria, we will need to make trade-offs between materials and study ways to work around the shortfalls inherent in the materials. We expect our research to lead to solutions to these problems for the microelectronic device industry."