부산대학교 도서관

Previous studies have measured conventional power MOSFET [1] and IGBT [2] operation down to the temperature of 4.2K. However, super-junction (SJ) devices such as CoolMOS TM have only been characterised down to 80K. This paper presents the cryogenic behaviour of HEXFET®, MDMesh TM and CoolMOS TM down to the temperature of 20K for the first time. A linear reduction in breakdown voltage with temperature was observed down to approximately 150K, below which the breakdown voltages saturated at higher values than predicted. The gradient of the linear reduction and the temperature at which the saturation begins depend on the dopant concentration of the drift region and on the device structure. The on-state resistances were found to reduce dramatically down to 50K; below this temperature, some SJ devices exhibited significant carrier freeze-out effects while conventional devices like HEXFET® were less affected.