SEM observation of p-n junction in semiconductors using fountain secondary electron detector

When we observe a p-n junction in a certain semiconductor using scanning electron microscope, the p-type region may be brighter than n-type region in a secondary electron (SE) image. To clarify this origin, the p-n junctions in 4H-SiC was observed using fountain secondary electron detector (FSED) as shown in Fig (a). The original FSED image in (b) shows the brighter p-region than the n-region. By subtracting background, the line profiles of FSED signal across p-n junction were recorded according to the SE energies. The analysis of these curves gives us the detailed information of p-n junction.258