A method of characterizing a wide-bandgap semiconductor material is provided. A substrate is provided, which includes a layer stack of a conductive material layer, a dielectric material layer, and a wide-bandgap semiconductor material layer. A mercury probe is disposed on a top surface of the wide-bandgap semiconductor material layer. Alternating-current (AC) capacitance of the layer stack is determined as a function of a variable direct-current (DC) bias voltage across the conductive material layer and the wide-bandgap semiconductor material layer. A material property of the wide-bandgap semiconductor material layer is extracted from a profile of the AC capacitance as a function of the DC bias voltage.