Characterization of the SiO2/SiC Interface with Impedance Spectroscopy

Abstract

Using impedance spectroscopy (IS) for the characterization of SiO2/4H-SiC (MOS) structures, insight on the capacitive and resistive contributions in different physical regions of the MOS structures is obtained. Changing the DC bias conditions, semiconductor, interface as well as oxide traps can be detected. The MOS capacitance, as extracted from IS data, is different from the one obtained using capacitance voltage (CV) measurements, due to the possibility of distinguishing different charge transfer processes using IS. For instance, in the investigated capacitors, a clear contribution is revealed from ionic conduction processes at bias voltages close to zero.