Scalable, Wide Bandgap Integrated Circuit Technology for Wide Temperature, Harsh Environment Applications

ABSTRACT: During this program, United Silicon Carbide, Inc. (USCi) will develop basic analog and digital circuit blocks capable of operation up to 500oC, based on 4H-SiC complementary lateral JFET technology. The following integrated circuits will be designed (i) operational amplifier; (ii) voltage reference circuit; and (iii) logic gates with the following functions NOT, NAND, NOR, AND, OR. In order to reduce the complexity of the fabrication process and to ensure better compatibility with the standard processes available in modern silicon fabs, we propose to develop a completely planar lateral JFET technology to realize a complementary JFET structure that would enable more efficient and faster logic architectures for digital and mixed signal high temperature capable integrated circuits. This Phase I study will provide concrete information to confirm the feasibility of the idea and critical information for the major R & D work in Phase II aimed at developing and commercializing basic analog and logic circuits capable of operation up to 500oC. BENEFIT: Various harsh environment applications, such as the propulsion systems of hybrid and all-electric vehicles, electrical actuation on military and commercial aircraft, space exploration, and energy exploration applications, require compact and efficient electrical power systems with reduced cooling requirements. Power modules based on Silicon Carbide (SiC) are able to provide the required performance in these application areas due to the unique material properties of SiC. The control electronics, used to control high power modules, need to be placed in close proximity to the power switches (to reduce noise and interference), where operation at elevated ambient temperatures above 200oC is required and higher switching frequency is desired to benefit from the capabilities of SiC power modules. In various sensing systems, placing the sensing circuit close to the actual sensor substantially reduces noise and interference problems and improves system reliability. Electronic circuits based on silicon devices are generally not able to operate at temperatures above 200oC because of excessive junction leakage currents, and even the most advanced silicon-on-insulator (SOI) devices are limited to about 300oC. While SOI circuits have been demonstrated to operate at 300oC, a common rating among the commercial products is 225oC. Wide band-gap materials can be used to build devices, capable of operation at higher temperatures. Silicon carbide (SiC) is the most mature material for high temperature applications. Even when operating at the same temperatures as SOI circuits (200oC-250oC), a better stability and reliability can be expected from circuits based on SiC, as they will not be operating at a condition that is close to their absolute maximum capabilities.