A deep-level transient spectroscopic study was made of deep-level defect centers on the n-side of p+n junction diodes which had been prepared by low- and high-temperature Al-ion implantation of n-type 6H-material. Two shallow Al-acceptor levels were detected in the n-type region, just beyond the implantation depth, via their minority-carrier emission signatures. The predominant level was situated at 0.26eV above the valence band, and was associated with a shallower level of low intensity. A comparison with photoluminescence results suggested that the predominant level (labelled Ak) and the shallower level (labelled Ah) were associated with the cubic and hexagonal lattice sites, respectively. Contrary to previously reports, which had noted the presence of many different implantation-induced donors within the implantation region, only a single deep donor level, at Ec - 0.44eV, was found to occur in the post-implantation region. This indicated that the various crystal damage sites had differing spatial distributions.

S.Fung, M.Gong, C.D.Beling, G.Brauer, H.Wirth, W.Skorupa: Journal of Applied Physics, 1998, 84[2], 1152-4