Off-axis electron holography was used to map the electrostatic potential distribution of threading screw dislocations in differently n-doped 4H–SiC epitaxial layers. Observed phase contrast indicated the presence of a negatively charged dislocation core. Comparison between experimental and simulated potential profiles indicated that the density of trapped charges increased for a higher doped epilayer. Assuming a single level of the trap at the core, the ionization energy of the trap was calculated to be 0.89eV.

Electronic Structure Analysis of Threading Screw Dislocations in 4H–SiC using Electron Holography. S.Chung, R.A.Berechman, M.R.McCartney, M.Skowronski: Journal of Applied Physics, 2011, 109[3], 034906