Investigation of Electrical Characteristics on SiC MOSFET and JBS-Integrated MOSFET at Cryogenic Temperatures

In this article, a 1.2-kV conventional MOSFET and a MOSFET integrated with a junction barrier Schottky diode (JBSFET) were fabricated with a consistent process flow. The electrical characteristics of MOSFET and JBSFET, including static performance, structural capacitance, and switching performance have been systematically analyzed in the temperature range of 80-300 K. Experimental results show that the third quadrant voltage drop of JBSFET is smaller than MOSFET and hardly changes with decreasing temperature. The gate-drain capacitance of MOSFET and JBSFET increases by more than 50% at 80 K, due to the cryogenic incomplete ionization of the P-Base. The switching performance of the two devices is affected by the temperature dependence of threshold voltage, structural capacitance, and interface state charges, manifesting in a reduction in turn-on speed and voltage tailing at cryogenic temperatures. According to the results, JBSFET has better potential for low-temperature applications due to its stable third-quadrant characteristics. The cryogenic incomplete ionization of the P-Base region has a significant impact on the output characteristics, structural capacitance, and switching performance.