Gate Capacitance and Conductance-Voltage Characteristics of Vertical 4H-SiC MOSFETs

We have characterized gate capacitive and conductive behaviors of commercial Si and 4H-SiC vertical MOSFETs that have never been reported previously. The characteristics and possible physical reasons are determined and corroborated with device simulations. The measurements were carried out on different 1200V 4H-SiC MOSFETs from several vendors by impedance analyzer. Typical C-V characteristics of gate-controlled diodes are observed in those MOSFETs, while several conductance peaks are also captured in G-V measurements. These conductance peaks, reproduced with numerical simulations, are not necessarily related to the behavior of any interface states at the gate oxide/ 4H-SiC interface.