Impact of Cu contamination on the electrical properties of a direct silicon bonded (110)/(100) interfacial grain boundary

Cu contamination of a "model" grain boundary (GB) created by direct silicon bonding of (110)/(100) wafers has been investigated by monitoring the hole emission from GB states. It is found that the electronic states at the clean GB are localized, whereas following Cu contamination, they transform into bandlike states with much larger hole capture cross sections. Following an increase in Cu contamination at the GB by a quenching anneal, the density of GB states decreases, while the GB neutral level remains constant, essentially independent of contamination temperature. It is believed that the electrically active Cu-related states present at the GB are generated from the surfaces of localized Cu precipitates, whereas quench cooling from a higher contamination temperature produces a lower density of large precipitates which results in a reduced density of Cu-related GB states. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3032655]