V. Higgs et al., CATHODOLUMINESCENCE IMAGING OF MISFIT DISLOCATIONS IN SI SIGE EPITAXIAL LAYERS - THE INFLUENCE OF TRANSITION-METAL CONTAMINATION/, Materials science & engineering. B, Solid-state materials for advanced technology, 24(1-3), 1994, pp. 48-51
Cathodoluminescence (CL) spectroscopy and CL imaging have been used to
characterize misfit dislocations in as-grown Si/SiGe epilayers and th
ose contaminated with transition metal. The misfit dislocations in the
as-grown layers showed no radiative recombination (D bands) but only
the band exciton features from the Si substrate. CL monochromatic imag
ing with the Si substrate luminescence revealed dark line contrast, as
sociated with non-radiative recombination at the misfit dislocations.
Following contamination with low levels (10(10)-10(12) atoms cm-2) of
the transition metals Cu, Au, Fe or Ni and annealing, the D bands (D1-
D4) were observed. CL images indicated that D1 and D2 are associated w
ith point defects and that D3 and D4 are related to radiative recombin
ation at the misfit dislocations. After higher contamination with Cu,
Au or Ni, when the misfit dislocations were decorated by metal-related
microprecipitates, the radiative recombination at the dislocation was
quenched. The CL dark line contrast was observed from all the samples
, independent of contamination treatment.