Photoluminescence Spectroscopy of 4H- and 6H-SiC.
Abstract
Typical undoped bulk grown SiC shows n- or p-type conductivity due to residual impurities such as nitrogen, boron, or aluminum. In order to produce high resistivity material, vanadium can be used as a compensating dopant. Since vanadium is an amphoteric dopant in SiC, it produces either a donor state, V sub Si (4+) (3d sup 1 )-> V sub Si(5+) (3d sup 0), or an acceptor state, V sub Si(4+) (3d sup 1)-> V sub Si(3+)(3d sup 2). Thus, vanadium doping can compensate both n- and p-type conductivity. In this work, vanadium doped and undoped 4H- and 6H-SiC grown by the sublimation method have been studied using low temperature photoluminescence (PL). It was found that the luminescence observed between 0.85 to 0.95 eV of the intra-3d-shell transition of V sub Si(4+) (3d sup 1) increased by an order of magnitude in samples intentionally doped with vanadium compared to samples unintentionally doped. In addition, the dominant visible-region luminescence was attributed to titanium which is an isoelectronic trap in SiC. The presence of a broad peak centered at approx. 1.90 eV in some samples is believed to be attributed to donor-acceptor pair recombination between a Ti sub Si-N sub c complex donor and the boron defect complex acting as an acceptor. Finally, the Ti sub Si-N sub c complex donor location in the bandgap of 6H-SiC is estimated to be E sub c-0.54 eV.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1994
- Accession Number
- ADA289326
Entities
People
- William A. Davis
Organizations
- Air Force Institute of Technology