It was recalled that the plastic relaxation of SiGe layers on (100)Si led to the formation of misfit dislocations at the hetero-interface and of threading dislocations throughout the heterostructure. A deep-level transient spectroscopic investigation was made here of dislocations in n-type Si/Si0.88Ge0.12/Si heterostructures that had been grown by means of selective epitaxy using low-pressure chemical vapor deposition. Deep-level transient spectroscopy was used to detect the deep states that were associated with dislocations. Measurements were performed on large-area samples (63% relaxation) as well as on small-area samples (4% relaxation) that had been grown selectively on the same wafer. The bias-dependent deep-level transient spectroscopic peak heights were consistent with a spatially varying dislocation density. This variation, and the corresponding deep-level transient spectroscopic peaks for large and small areas, permitted one of the deep levels to be associated with misfit dislocations at the hetero-interface. A second one was associated with threading dislocations, and a third one was associated with defects that were located in the SiGe layer; near to the interface.

O.Chretien, R.Apetz, L.Vescan: Semiconductor Science and Technology, 1996, 11[12], 1838-42