A Charge Balanced Vertical Power MOSFET with Record High Balliga’s Figure of Merit: Design and Investigation

In this work, we design and simulate a high-performance vertical power MOSFET with a charge balanced drift layer, which modulates the R-BV relation from super quadratic to linear. The proposed device is designed with a super junction drift layer which modulates the R-BV relation from super quadratic to linear. The proposed device has the source and channel regions isolated from the super junction drift layer. This results in a significant improvement in the performance of the proposed device in comparison to the other conventional devices, in terms of Balliga’s figure of merit. A 2D TCAD simulation study reveals that the proposed device with an epitaxial layer thickness of 50 μm shows an ON resistance of 3.84mΩ.cm for a break down voltage of 833 V, which is the lowest among the resistances reported in the previous literature at this breakdown voltage. Further, the study of charge imbalances and the capacitance analyses including the calculation of gate charge has also been done. The values of Balliga’s figure of merit (FOM) calculated for all the drift thicknesses of the proposed structures are significantly outperforming the conventional super junction structures reported so far.