A Physics-Based Modeling of Interelectrode MOS Capacitances of Power MOSFET and IGBT

The conventional and widespread modeling of interelectrode capacitances of power mosfet and insulated gate bipolar transistor is based on a single dipolar representation of the electric charge induced in the intercellular drain region. In this paper, it is proved by some experimental tests that this representation, symbolized by the gate transfer capacitance $C_{{\rm GD}}$, may not be physics-based, especially under negative gate polarization. Then, it is demonstrated that interelectrode MOS capacitances are fundamentally of three-port coupling origin. A physical capacitive model, available for both gate capacitance and gate transfer capacitance, is detailed, implemented in a simulation software, and compared with experiment.