Microscopic photoluminescence evaluation of bright spots in Fe-doped InP wafers

Microscopic non-uniformity of Fe-doped semi-insulating InP wafers has been investigated by photoluminescence spectroscopy and mapping. A deep-level em ission with a peak around 1.1 eV appears at 15 K in addition to the band-ed ge emission due to the exciton recombination at 1.42 eV. An intensity ratio of the 1.1 eV band to the 1.42 eV band is correlated positively with the F e concentration, suggesting that the 1.1 eV band is associated with Fe. The intensity of the 1.1 eV band decreases at bright spots and lines with an o pposite intensity in contrast to the band-edge emission. This gives strong evidence for the idea that the origin of the bright spot and line is an Fe- depleted region where Fe is gettered by defects, most probably dislocations , through their strain field. (C) 2000 Elsevier Science B.V. All rights res erved.