Comparative Performance Evaluation and Analysis of High Voltage Superjunction, Charge-Balanced, and Conventional 4H-SiC DMOSFETs at Cryogenic and High Temperatures

We have experimentally investigated the static performance of 3.3kV Superjunction (SJ), a 3.3kV Charge-Balanced (CB), and 1.2kV commercial conventional (Conv) 4H-SiC DMOSFETs between cryogenic (77K) and high (423K) temperatures. Our results show that the RON,sp increases by 2.6^x, 2.8^x, and 3.4x from 300K to 77K for the 3.3kV SJ and CB, and 1.2kV Conv devices, respectively, showing a characteristic “bathtub”-shaped temperature dependence. The extracted BVDSS temperature coefficients are +0.06^%/K, +0.02^%/K, and +0.01%/K (223K to 423K) for the 3.3kV SJ and CB, and 1.2kV Conv DMOSFETs. Extracted field-effect mobility of SJ and CB devices is generally proportional to T, indicating coulombic scattering being dominant. The projected RON,sp vs. BV trade-off at 77K is mainly limited by channel resistance up to 5 kV in Conv devices and up to 10 kV in SJ devices, due to inversion mobility degradation and increase of threshold voltage. For the CB DMOSFET, it is expected to fall between that of Conv and SJ devices due to the parasitic JFETs in the CB drift region. These results establish a benchmark for the static performance of 4H-SiC SJ and CB DMOSFETs, offering valuable insights into their suitability for low- and high-temperature applications.