Annealing behavior of the carbon vacancy in electron-irradiated 4H-SiC

Electron paramagnetic resonance (EPR) was used to study the annealing behavior of the positively charged carbon vacancy ($\mathrm{EI}5$ center) in electron-irradiated $4\mathrm{H}\text{-}\mathrm{SiC}$ . At $\sim 1000°\mathrm{C}$ the EPR signal of the defect starts decreasing gradually. Clear ligand hyperfine structure is still observed after annealing at $1350°\mathrm{C}$ , while the central line can be detected after a $1600°\mathrm{C}$ anneal. A similar annealing behavior was also observed for the $\mathrm{EI}6$ center suggesting that this defect may be also the positively charged carbon vacancy but at the hexagonal lattice site.