High-purity and weakly-doped n-type epitaxial layers of 4H-SiC were implanted with N and C ions by using energies in the MeV range and doses from 2 x 108 to 109/cm2. Post-implant annealing was performed at 1100C prior to sample analysis by deep-level transient spectroscopy (DLTS). A drastic and irreversible instability of the prominent EH7 deep-level defect occurred during the first DLTS temperature scan because of the electric field applied during the measurements. Depending on the implanted species, EH7 could decrease (N implants) as well as increase (C implants) in strength and the effect was attributed to charge-state controlled annealing and formation processes of EH7. The origin of EH7 was discussed and the experimental data support a model invoking interstitial C atoms.

Electric Field Assisted Annealing and Formation of Prominent Deep-Level Defect in Ion-Implanted n-Type 4H-SiC. J.Wong-Leung, B.G.Svensson: Applied Physics Letters, 2008, 92[14], 142105