This Partnerships for Innovation: Building Innovation Capacity project from Auburn University will be focused on building the basic foundations of a silicon-based high temperature integrated circuit technology. The final goal is to demonstrate a major polytype of silicon carbide (4H-SiC) metal-oxide semiconductor field-effect-transistor (that is, a 4H-SiC MOSFET)-based operational amplifier, operating at 250°C or higher. 4H-SiC is a wide-band gap semiconductor with a high critical breakdown field, high thermal conductivity, good bulk electron mobility, high chemical inertness, and mechanical hardness. These properties make 4H-SiC an extremely attractive material for electronics operating in harsh environments and at temperatures higher than 250°C, conditions under which conventional silicon-based electronics are very inefficient. In addition, the ability of SiC to oxidize to silicon dioxide, an insulator, naturally makes for MOSFETs. MOSFETs are voltage controlled electronic switches that are preferred over other devices as they offer a great deal of flexibility for circuit design. An efficient 4H-SiC MOSFET-based integrated circuit (IC) technology operating at high temperature will have a positive socio-economic impact in a variety of industrial and military applications. A limitation for employing 4H-SiC MOSFETs for this purpose is the low mobility of electrons in the conducting channel. This is primarily associated with a high density of traps at the oxide-SiC interface that results in carrier trapping and reduction of channel mobility. Recently, the Auburn group has demonstrated an advanced interface passivation process by incorporating phosphorus at and near the oxide-4H-SiC interface. This process results in a significantly reduced trap densities compared to the industry standard processes and accordingly results in at least a factor of two higher electron channel mobility compared to the state-of-the-art. The higher mobility is expected to result in significantly superior SiC operational-amplifiers. The intellectual merit of this proposal lies in the transfer of a fundamental materials science discovery to advanced applications taking future commercialization issues into consideration.
The broader impacts of this research are increasing U.S. technological competitiveness, increasing the business viability of small business partners, and developing students capable of contributing to the semiconductor industry. A high performance 4H-SiC IC technology has the potential to open a variety of new applications areas and markets. Some notable application areas are sensing and control circuits for geothermal, automotive and aeronautical sectors. Such technologies will have significant positive impact on U.S. competitiveness. The increased innovation capacity of the small business partners resulting from the success of this program would set the stage for building commercial prototypes to penetrate niche markets, increasing their business viability, and thus a future role in the nascent silicon carbide semiconductor industry. The success of such a technology would also create new possibilities for other end-user application-oriented businesses. An important aspect of the program is related to the education of graduate students. Students involved in this project will be exposed to the "food chain of semiconductor technology", ranging from basic semiconductor materials science to technology development and applications during their master's or doctoral research. Hands-on training related to a wide range of scientific and engineering problems will result in the development of young, highly trained scientists for the U.S. semiconductor industry. Additionally, the program will include workshops for high school students and teachers. Finally, existing close interactions with Tuskegee University, a local historically black university will be consolidated in this program.
Partners at the inception of the project are the lead institution: Auburn University; and two small technology-based businesses: CoolCAD Electronics LLC (College Park, MD), which performs analysis, design and prototyping for cryogenic, SiC and infrared (IR) electronics; and United Silicon Carbide Inc.(Monmouth Junction, NJ), which focuses on the design, fabrication, and commercialization of SiC technologies.
