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The carbon vacancy (V C) 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 V C concentration is typically in the range of 10 12 cm-3 and after device processing at temperatures approaching 2000 C, it can be enhanced by several orders of magnitude. In the present contribution, we show that the cooling rate after high-temperature processing has a profound influence on the resulting V C concentration where a slow rate promotes elimination of V C. Further, isochronal annealing of as-grown and as-oxidized epi-layers protected by a carbon-cap was undertaken between 800 C and 1600 C. The results reveal that thermodynamic equilibrium of V C is established rather rapidly at moderate temperatures, reaching a V C concentration of only a few times 10 11 cm-3 after 40 min at 1500 C. Hence, the …
Trans Tech Publications Ltd
Publication date: 
1 Jan 2016

Hussein M Ayedh, Viktor Bobal, Roberta Nipoti, Anders Hallén, Bengt Gunnar Svensson

Biblio References: 
Volume: 858 Pages: 331-336
Materials Science Forum