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

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The conventional and widespread modeling of interelectrode capacitances of power <emphasis emphasistype="smcaps">mosfet</emphasis> 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 <formula formulatype="inline"><tex Notation="TeX">$C_{{\rm GD}}$</tex></formula>, 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. </para>