Simulation study of conduction-state charge imbalance in high voltage super-junction power MOSFET

In high voltage super-junction (SJ) power transistor, to achieve high breakdown voltage, exact charge balance between the p-pillar and n-pillar is required. However, if there is a charge imbalance due to doping difference between the n and p pillars, the field profile gets disturbed, and BV is reduced. Effect of the gate voltage variation on the forward blocking capability is investigated using simulation. The electric field profile and the potential contour distribution are investigated during conduction state using simulation tool. Results are summarized in the form of FBV-V_GS plots for three different cases of possible drift layer doping variation.