Researchers from North Carolina State University say they have developed a new manufacturing process and chip design for silicon carbide (SiC) power devices. The process, called PRESiCE, was developed specifcially to make it easier for companies to enter the SiC marketplace and develop new products.
“PRESiCE will allow more companies to get into the SiC market, because they won’t have to initially develop their own design and manufacturing process for power devices – an expensive, time-consuming engineering effort,” says Jay Baliga, Distinguished University Professor of Electrical and Computer Engineering at NC State and lead author of a paper on PRESiCE that will be presented later this month. “The companies can instead use the PRESiCE technology to develop their own products.”
Until now, SiC manufacturing processes have been kept proprietary. This has limited the market and kept the cost of SiC devices high. The NC State researchers developed PRESiCE to address this bottleneck with the goal of lowering the barrier of entry to the field for companies and increasing innovation.
The PRESiCE team worked with a Texas-based foundry called X-Fab to implement the manufacturing process and have now qualified it – showing that it has the high yield and tight statistical distribution of electrical properties for SiC power devices necessary to make them attractive to industry. Baliga says the team has made 1.2-kV state-of-the-art devices (power MOSFETs, ACCUFETs, and JBS rectifiers) in the X-Fab foundry. (JBS or junction barrier Schottky rectifiers combine a PiN a Schottky diode. An ACCUFET is an accumulation channel FET, basically a FET with a low forward voltage.) In addition, the team says they have monolithically integrated a JBS fly-back rectifier into the power MOSFET structure to create the power JBSFET which allows saving significant (~40%) chip area and reducing package count in half.
Right now, SiC devices cost about five times more than silicon power devices. “Our goal is to get it down to 1.5 times the cost of silicon devices,” Baliga says. “Hopefully that will begin the ‘virtuous cycle’: lower cost will lead to higher use; higher use leads to greater production volume; greater production volume further reduces cost, and so on. And consumers are getting a better, more energy-efficient product.”
The researchers have already licensed the PRESiCE process and chip design to one company, and are in talks with several others.
The paper, “PRESiCE: PRocess Engineered for manufacturing SiC Electronic-devices,” is scheduled to be presented at the International Conference on Silicon Carbide and Related Materials, held Sept. 17-22 in Washington, D.C. The paper is co-authored by W. Sung, now at State University of New York Polytechnic Institute; K. Han and J. Harmon, who are Ph.D. students at NC State; and A. Tucker and S. Syed, who are undergraduates at NC State. The work was supported by PowerAmerica, the Department of Energy-funded manufacturing innovation institute that focuses on boosting manufacturing of wide bandgap semiconductor-based power electronics.