Silicon carbide (SiC) bipolar junction transistors (BJT's) promise compact, high power density, rugged, low loss power switching for motor control and electric power conversion compared to silicon (Si) devices. High power density is achieved with the wide band gap, high thermal conductivity, high breakdown voltage and high switching frequency capability of SiC. The higher switching frequency enabled by SiC allows smaller power supply components, resulting in development of more compact power systems. SiC BJT's have received increasing attention due to difficulties with gate channel mobilities for SiC MOSFET-type devices. However, as SiC bipolar devices are scaled to higher power, breakdown voltage decreases. This decrease in breakdown voltage is ascribed to poor material properties, particularly in epitaxial layers. In this SBIR program Extreme Devices, in collaboration with Rensselaer Polytechnic Institute, proposes to design and fabricate high power SiC BJT's using state-of-the-art high power device design rules and Extreme Devices' novel supersonic molecular beam epitaxy process. The combination of device design and the improved epitaxial SiC provided by supersonic beams will deliver increased device performance. In Phase I, demonstration 300V, 5A SiC BJT's will be designed, fabricated and characterized. Phase II will design, fabricate and package larger, higher power devices.High power SiC BJT's have advantages over both Si BJT's (higher thermal conductivity, higher breakdown voltage, higher temperature operation, lower losses and higher switching frequency) and SiC MOSFET's. These properties open the door to production of smaller, more powerful circuitry for both military and commercial power control and distribution.
Keywords: Transistor, Silicon Carbide, Electronic Materials, Power Semiconductor, High Temperature
