Investigation of defect levels in 6H‐SiC single crystals

Abstract

PACS 61.72. Ji, 71.55.Ht Defect levels in the n-type bulk 6H-SiC have been investigated by deep level transient spectroscopy (DLTS) and photoinduced transient spectroscopy (PITS). From the DLTS spectra, four electron traps at E c -0.53 eV (T1), E c -0.64 eV (T2), E c -0.67 eV (T3) and E c -0.69 eV (T4) , respectively, were revealed. The centers T1, tentatively identified with carbon vacancies, were found to be located in the vicinity of dislocations. The centers T2 and T3 were assigned to the known deep-level defect Z 1 /Z 2 occurring both in 4H and 6H SiC polytypes. The PITS measurements revealed two shallow traps with activation energies 20 and 60 meV, as well as a deep trap at 0.66 eV. The origin of the first trap still remains unclear. The latter two traps are tentatively identified with a nitrogen atom in hexagonal site and a complex involving a boron atom and silicon antisite, respectively.

Compensating defect centres in semi-insulating 6H-SiC

“…The centres TU10 (500 meV) and TU11 (650 meV) can be identified with the known electron traps at E c -0.50 eV and E c -0.64 eV occurring either in the as grown or electron irradiated n−type 6H−SiC [20,21]. The former trap has been attributed to a carbon vacancy and the latter has been as− signed to a complex involving a silicon antisite [20,21] ture photoluminescence spectra [3,4].…”

“…The former trap has been attributed to a carbon vacancy and the latter has been as− signed to a complex involving a silicon antisite [20,21] ture photoluminescence spectra [3,4]. However, the micro− scopic structure of this defect still remains unknown.…”

Characterization of epitaxial 4H-SiC for photon detectors

“…The respective activation energies E T , apparent capture cross sections σ T and concentrations N T are listed in table 1. In particular the peak B, corresponding to an activation energy of 0.64 eV and an apparent capture cross section of 4.7×10 −15 cm −2 , can be identified with the well-known Z 1 /Z 2 defect, typical of both as-grown 4H and 6H-SiC [18][19][20][21]. Although different authors have investigated the characteristics of this defect, its nature has not been unambiguously established.…”