Electron paramagnetic resonance of deep boron in SiC

In this letter we report the first EPR observation of deep boron centres in silicon carbide. A direct identification of the boron atom involved in the defect centre, considered as deep boron, has been established by the presence of hyperfine interaction with B-11 and B-10 nuclei in isotope enriched 6H-SiC:B crystals. Deep boron centres were shown from EPR spectra to have axial symmetry along the hexagonal axis. An correspondence between the EPR spectra and the luminescence, ODMR and DLTS spectra of deep boron centres have been indicated. The structural model for deep boron centre as a boron vacancy pair is presented and the evidences for bistable behaviour of deep boron centres are discussed.