Deep levels related to the carbon antisite-vacancy pair in 4H-SiC

Photo-induced current transient spectroscopy (PICTS) and electron paramagnetic resonance (EPR) are used to study irradiation-induced defects in high-purity semi-insulating (HPSI) 4H-SiC. Several deep levels with the ionization energy ranging from 0.1 to similar to 1.1 eV have been observed in irradiated and annealed samples by PICTS. Among these, two deep levels, labeled E370 and E700 at similar to 0.72 and similar to 1.07 eV below the conduction band, respectively, are detected after high-temperature annealing. The appearance and disappearance of these two deep levels and the EPR signal of the positive C antisite-vacancy pair (CSiVC+) in the sample annealed at 1000 and 1200 degrees C, respectively, are well correlated. Based on data from PICTS and EPR and the energies predicted by previous calculations for different charge states of dominant intrinsic defects, the E370 and E700 levels are suggested to be related to the charge transition levels (0|-) and (+|0), respectively, of the C antisite-vacancy pair. The activation energy of E-a similar to 1.1 eV in commercial HPSI 4H-SiC materials is, therefore, reassigned to be related to the single donor (+|0) level of CSiVC.Funding Agencies|Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR 2016-05362, VR 2016-04068]; EU H2020 project QuanTELCO [862721]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [KAW 2018.0071]; Japan Society for the Promotion of ScienceMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science [JSPS KAKENHI 20H00355, 18H03770]; [25390067]