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.