scope:

For SiC MOSFET, the gate-charge characteristic behaves different to conventional silicon power MOSFETs. The most distinct point is the absence of a real Miller plateau. Due to short n-channels, which are typically used in SiC MOSFETs, practically a Miller "ramp" is measured. The standard QG extraction methods [1] cannot be easily applied. Furthermore, the presence of a VGS,TH hysteresis [2] makes it necessary to define clearly the starting gate voltage for QG measurement and extraction. The following document defines a QGS,TOT, QGD and QGS,TH which can be extracted from a measured QG waveform.

The test and extraction method can be applied to the following:

• N-Channel SiC MOSFET (vertical structure)

• Wafer and package levels