It was recalled that low-temperature photoluminescence spectroscopy was a very sensitive tool for investigating the presence of dislocations, and that the main dislocation-related bands (D1-D4) could be attributed to a range of causes. These included intrinsic properties of the dislocations, and impurity-related phenomena. The photoluminescence was a competitive recombination process, and non-radiative processes had to be measured in order to understand the overall effect of impurities. The photoluminescence spectroscopy sampled a volume which was large in comparison with the dislocation itself, and therefore had an averaging effect. High resolution room temperature photoluminescence mapping was used to detect defects in wafers. A comparison with defect-etching results showed that there was a one-to-one correlation between the defects which were detected by photoluminescence micro-scans and those revealed by defect etching. Whole-wafer mapping revealed a number of differing defect types epilayers. The ability to record whole-wafer photoluminescence maps facilitated the rapid identification of inhomogeneities and defects. High-resolution photoluminescence micro-maps revealed that the defect area contained a high density of misfit dislocations, and that the nucleation site exhibited strong non-radiative recombination. A common defect type was analysed by using plan-view transmission electron microscopy and optical microscopy, and these results revealed the presence of a high density of defect loops and stacking faults. These were consistent with the high recombination rate at the defect site.

Photoluminescence Characterization of Defects in Si and SiGe Structures. V.Higgs, F.Chin, X.Wang, J.Mosalski, R.Beanland: Journal of Physics - Condensed Matter, 2000, 12[49], 10105-21