Mirror electron microscope observations were conducted for a 4μm-thick n-doped 4H-SiC epitaxial layer. If the sample was simultaneously illuminated with ultra-violet light of a slightly greater energy than the band-gap energy of 4H-SiC, in-grown stacking faults could be clearly observed in mirror electron microscopic images. These observations were performed non-destructively, as almost all irradiated electrons returned without impinging the sample surface due to the negative voltage applied to the sample. High spatial resolution observation via mirror electron microscopy showed that multiple in-grown stacking faults were stacked up. The phenomenon in which the contrast of the in-grown stacking faults vanished in the absence of ultra-violet illumination and under ultra-violet illumination with a lower energy than the band-gap energy revealed that the origin of the contrast was the negative charging of in-grown stacking faults trapping electrons excited by ultra-violet light.

Non-Destructive Observation of in-Grown Stacking Faults in 4H-SiC Epitaxial Layer using Mirror Electron Microscope. M.Hasegawa, T.Ohno: Journal of Applied Physics, 2011, 110[7], 073507