Regensburg 2002 – wissenschaftliches Programm
HL 33.3: Vortrag
Donnerstag, 14. März 2002, 11:00–11:15, H15
Erbium-implanted 4H and 6H silicon carbide — •Sergey A. Reshanov1, Oliver Klettke1, Gerhard Pensl1, and W.J. Choyke2 — 1Institut of Applied Physiks, University of Erlangen-Nürnberg — 2Department of Physics and Astronomy, University of Pittsburgh, USA
Implants of Er, Xe, Al and N with energies ranging from 120 keV to 2 MeV were carried out in n- and p-type 4H-/6H-SiC. Deep level transient spectroscopy (DLTS) and low temperature photoluminescence (LTPL) investigations were conducted on identical samples to identify and to correlate Er-related and implantation-induced defect centers. In n-type SiC implanted with Er, we found well-known DLTS damage levels: ID4, RD1/2, RD3 for the 4H polytype and ID6, ID7, Z1/Z2 for the 6H polytype. A strong Er-related line pattern was observed in the LTPL-spectra of n-type SiC. In p-type SiC implanted with Er, two DLTS peaks could unambiguously be associated with Er: Ev+0.75/0.78 eV in 4H and Ev+0.78/0.79 eV in 6H. On the other hand, no Er-related luminescence lines were observed in p-type SiC. The activation energy of the observed Er-related levels is independent of the applied electric field indicating that these centers are donor-like. Further the activation energy of Er-related centers decreases with increasing implanted Er concentration. In p-6H-SiC, we observed an implantation-induced defect level KR1/KR2 at Ev+0.4 eV. Conversion of p-type SiC into n-type by nitrogen implantation, recovers the photoluminescence. We suggest that the Er-associated levels in the lower half of the bandgap are likely not involved in the energy transfer mechanism, which is responsible for the Er luminescence.