Silicon research promises better, stronger computer chips

Contact: Bob Ratliff

A team of Mississippi State University electrical engineers is turning sand into the next generation of semiconductors.

Their research focuses on silicon carbide technology for use in semiconductors, the building blocks for computer chips.

Commonly found in sand, silicon is the basic material for semiconductors. Adding carbon to silicon results in a superior product.

"The bonds between silicon and carbon are much stronger than the bonds between silicon and other additives," said associate professor Mike Mazzola. "The result is a material that is outstanding for high temperature, high voltage and high frequency applications."

Silicon carbide semiconductors can cost up to 1,000 times more than the garden variety silicon devices, but they are much more reliable. And, since one silicon carbide chip can replace several silicon devices in high temperature applications, costs may actually decline.

Silicon carbide semiconductors can work at temperatures of more than 600 degrees Celsius, compared to only about 125 degrees for those made only with silicon.

"One example of silicon carbide's benefits in high-temperature applications is the flameout detectors that the U.S. Air Force uses in its jet engines," said Stephen Saddow, director of MSU's Emerging Materials Research Laboratory. "One silicon carbide sensor the size of your small fingernail can replace a football-size stack of 20 silicon sensors."

Working with Mazzola and Saddow is assistant professor Ben Blalock, who is investigating various silicon carbide chip designs at MSU's National Science Foundation Engineering Research Center.

The university's expertise in silicon carbide research led to a partnership with the General Electric Corp. earlier this year. Support for the work increased recently with a $1.5 million Department of Defense grant jointly provided by the Office of Naval Research and the Ballistic Missile Defense Organization.

Mazzola said the offices Mississippi's congressional delegation, including United States senators Trent Lott and Thad Cochran (R-Miss.) and congressman Chip Pickering (R-Miss.), devoted considerable time to gaining government support for the technology.

"The support the university has received from our congressional delegation has helped Mississippi State achieve a leadership position in this fast growing technology," he said.

Current research is focusing on something called silicon substrates, which provide the foundation on which all semiconductors are made. The ability to use silicon substrates has the potential to make the cost of silicon carbide devices about the same as ordinary silicon.

Already, the MSU team is looking ahead to the practical applications of their research.

"There is international interest in the application of this technology to electric vehicles," Mazzola said. "Power companies also are interested in the technology as a step in moving large amounts of electrical power across the nation's power grid."

Additional interest also will come from the startup of new silicon carbide production companies, which traditionally depend on university research for support and for engineering graduates with the expertise they need.

"From growing the initial material to manufacturing the final chip product, Mississippi State has expertise in all the areas," Saddow said. "That puts us in a very strong position to be an important factor in attracting silicon carbide electronics industries to Mississippi."