Dopant Profiling on 4H Silicon Carbide P+N Junction by Scanning Probe and Secondary Electron Microscopy

The availability of two-dimensional (2-D) dopant profiling techniques to Silicon Carbide (SiC) pn junction is discussed. We compared the results of scanning capacitance microscopy (SCM), scanning spreading resistance microscopy (SSRM), and secondary electron microscopy (SEM), where the cross-sections of a SiC wafer with n-type epi-layers and highly-doped p and n regions were used. The SSRM current image was very similar to the contrast in the SEM image. The junction depth derived from the SSRM profiles and SEM images showed a good agreement with that of secondary ion mass spectrometry (SIMS) data. On the contrary, the junction depth obtained from the SCM measurements was considerably underestimated. At present, the complementary use of SSRM and SEM is thought to be effective for the quantitative 2-D dopant profiling of SiC devices.