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The properties of cobalt as a contaminant in p-type silicon are studied by using cobaltimplanted wafers annealed by RTP or by RTP plus a low temperature furnace annealing. It is shown that after RTP most cobalt is under the form of CoB pairs. A quantification of cobalt contamination is provided based upon SPV measurements and optical pair dissociation. However, this quantification fails in furnace-annealed wafers because of the formation of a different level. It is shown that the CoB level is located near the band edges, whereas the level formed upon a low temperature furnace annealing is located near midgap. Besides, when the cobalt concentration is high enough a small fraction of cobalt is in a level different from the CoB pair even in RTP samples. This level can probably be identified with a previously observed midgap level. It is suggested that the same level is formed in RTP plus low temperature furnace …
Trans Tech Publications Ltd
Publication date: 
1 Jan 2005

Maria Luisa Polignano, Daniele Caputo, Davide Codegoni, Vittorio Privitera, M Riva

Biblio References: 
Volume: 108 Pages: 571-576
Solid State Phenomena