Forming Gas Annealing of the Carbon PbC Center in Oxidized Porous 3C- and 4H-SiC: An EPR Study

Abstract

Previous Electron Paramagnetic Resonance (EPR) studies identified the carbon dangling bond center as the main paramagnetic interface defect in 3C, 4H, 6H-SiC/SiO2. We demonstrate that this defect, called PbC center, can be passivated by forming gas annealing at 400°C. We have measured the PbC density at annealed 4H- and 3C-SiC/SiO2 interfaces and attributed its reduction to the transformation of the dangling bonds into EPR inactive C-H bonds. We have also studied the reverse phenomenon occurring during vacuum annealing at temperatures ranging from 600°C up to 1000°C and have determined a dissociation energy of ≈4.3 eV for the 3C and 4H polytypes.