A Study of Deep Defect Levels in Semi-Insulating SiC Using Optical Admittance Spectroscopy

Abstract

Optical admittance spectroscopy (OAS), supported by electron paramagnetic resonance (EPR) measurements, is used to identify the controversial vanadium acceptor levels in vanadium-doped semi-insulating (SI) 4H-SiC and 6H-SiC. The V 3+/4+ levels for the cubic site are likely located at E c ) 0.67 ± 0.02 eV and E c ) 0.70 ± 0.02 eV in 6H-SiC and E c ) 0.75 ± 0.02 eV in 4H-SiC. A peak at 0.87 ± 0.02 eV in the 6H-SiC is tentatively assigned to the same transition at the hexagonal site and the associated transition in 4H-SiC is thought to occur near 0.94 eV. All assignments are supported by the observation of V 3+ in the EPR spectrum.

Review of SiC crystal growth technology

“…The other variant, the application of the acceptor-like V 4+ to V 3+ transition exhibits a transition energy of ca. 0.8 eV ( [146] and references therein) and may compensate low doped n-type SiC. In this case, resistivity values of up to 10 11 Ωcm have been reported in literature (see e.g.…”

“…The donor-like V 4+ to V 5+ transition exhibits a transition energy of ca. 1.6 eV in SiC ( [146] and references therein) and compensates residual acceptors like boron and aluminum which leads to the high resistivity value of >10 15 Ωcm ( [82] for 4H-SiC:V). The other variant, the application of the acceptor-like V 4+ to V 3+ transition exhibits a transition energy of ca.…”