The Structure of the D-Center in Silicon Carbide — A Study with Electron Nuclear Double Resonance

Abstract

Boron-doped 6H-SiC has been studied for many years intensively. With DLTS the isolated boron acceptor and a deep donor called D-center was observed ([1] – [5]). The D-center was assumed to be a boron-vacancy complex. Up to now neither the structure nor the chemical composition of the D-center is known. In order to determine the electronic and microscopic structure of this defect we investigated boron doped 6H-SiC with Electron Nuclear Double Resonance (ENDOR). To correlate our ENDOR measurements with the energy levels known from DLTS for boron-related defects Photo-EPR (Electron Paramagnetic Resonance) and Photo-ENDOR measurements were carried out. From those measurements it is clear that with ENDOR indeed the D-centre was investigated. Our ENDOR measurements show that boron is a component of the D-center. From symmetry and quadrupole interaction observed we conclude that the D-center is not an isolated boron defect, but perturbed by an adjacent defect. The microscopic structure of the D-center as determined from our ENDOR analysis will be discussed.