Elimination of carbon vacancies in 4H-SiC employing thermodynamic equilibrium conditions at moderate temperatures
2015 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, no 25Article in journal (Refereed) PublishedText
The carbon vacancy (VC) is a major point defect in high-purity 4H-SiC epitaxial layers limiting the minority charge carrier lifetime. In layers grown by chemical vapor deposition techniques, the VC concentration is typically in the range of 1012cm-3, and after device processing at temperatures approaching 2000 °C, it can be enhanced by several orders of magnitude. In the present study, both as-grown layers and a high-temperature processed one have been annealed at 1500 °C and the VC concentration is demonstrated to be strongly reduced, exhibiting a value of only a few times 1011cm-3 as determined by deep-level transient spectroscopy measurements. The value is reached already after annealing times on the order of 1 h and is evidenced to reflect thermodynamic equilibrium under C-rich ambient conditions. The physical processes controlling the kinetics for establishment of the VC equilibrium are estimated to have an activation energy below ∼3 eV and both in-diffusion of carbon interstitials and out-diffusion of VC’s are discussed as candidates. This concept of VC elimination is flexible and readily integrated in a materials and device processing sequence.
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2015. Vol. 107, no 25
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:kth:diva-181817DOI: 10.1063/1.4938242ISI: 000368442100019ScopusID: 2-s2.0-84953309501OAI: oai:DiVA.org:kth-181817DiVA: diva2:901577
QC 20160208. QC 201602162016-02-082016-02-052016-02-16Bibliographically approved