An example method of characterizing a semiconductor sample includes measuring an initial value, Vin, of a surface potential at a region of a surface of the semiconductor sample, biasing the semiconductor sample to have a target surface potential value (V0) of 2V or less, and depositing a monitored amount of corona charge (ΔQ1) on the region of the surface after adjusting the surface potential to the target value. The method also includes measuring a first value, V1, of the surface potential at the region after depositing the corona charge, determining the first change of surface potential (ΔV1=V1−V0), and determining the first capacitance value C1=ΔQ1/ΔV1, and characterizing the semiconductor sample based on V0, V1, ΔV1, ΔQ1 and C1.