Simultaneous Interface Defect Density and Differential Capacitance Imaging by Time-Resolved Scanning Nonlinear Dielectric Microscopy

We investigate non-uniformity at SiO2/SiC interfaces by time-resolved scanning nonlinear dielectric microscopy, which permits the simultaneous nanoscale imaging of interface defect density (Dit) and differential capacitance (dC/dV) at insulator-semiconductor interfaces. Here we perform the cross correlation analysis of the images with spatially non-uniform clustering distributions reported previously. We show that Dit images are not correlated with the simultaneous dC/dV images significantly but with the difference image between the two dC/dV images taken with different voltage sweep directions. The results indicate that the dC/dV images visualize the non-uniformity of the total interface charge density and the difference images reflect that of Dit at a particular energy range.