Beryllium implantation induced deep levels in 6H-silicon carbide

Beryllium has been implanted into both n- and p-type 6H-silicon carbide (SiC) with high and low doses. Upon subsequent annealing at 1600°C, Beryllium implantation induced deep levels have been investigated by deep level transient spectroscopy. Five deep level centers labeled as BE1-BE5 were detected from high dose beryllium implantation produced pn junctions. A comparative study of low dose beryllium implanted n-type 6H-SiC sample proved that the BE1-BE3 centers were electron traps located at 0.34, 0.44, and 0.53eV, respectively below the conduction band edge. At the same time, the BE4 and BE5 centers were found to be hole traps situated at 0.64 and 0.73eV, respectively, above the valence band edge. In the case of beryllium implanted p-type 6H-SiC, four hole traps labeled as BEP1, BEP2, BEP3, and BEP4 have been observed. The observed levels of the hole traps BEP1 and BEP2 at 0.41 and 0.60eV, respectively, above the valence band agree well with those from the Hall effect data from material with beryllium acting as doubly charged acceptor. The other hole traps BEP3 and BEP4 at 0.76 and 0.88eV, above the valence band, respectively, are thought to be due to beryllium implantation induced defects or complexes.