Photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), and defect etching have been used to characterize epitaxial stacking faults (ESF) in silicon epilayers grown by low-pressure chemical vapor deposition (LPCVD) and oxidation-induced stacking faults (OISF) in high-purity float-zone (FZ) Si. No dislocation-related luminescence was observed from either ESFs or OISFs grown under clean conditions. Deliberate surface contamination, followed by annealing with Cu, Fe, Ni, Ag, or Au in the range 4×1012–2×1016 atoms cm−2 introduced dislocation luminescence features, with a maximum intensity at ≊4×1012 atoms cm−2. TEM examination revealed that there was no evidence for precipitation at low levels of contamination but as the contamination level increased metal-related precipitates were observed on the bounding partial dislocations.

The precipitation of oxygen in silicon and the resulting defect formation have been studied in bulk n-type wafers with varying oxygen content subjected to CMOS processing. The results are consistent with the previously reported existence of a threshold initial oxygen concentration for the occurrence of substantial oxygen precipitation during typical CMOS processing. Processed wafers from the sample set with the lower initial oxygen content exhibited marked radial non-uniformity of precipitation. Through the use of a combination of Fourier-transform infrared (FTIR) microspectroscopy, x-ray topography, chemical etching and TEM it has been possible to demonstrate a direct, quantitative correlation between t h e spatial variation of oxygen loss from solution and the associated defect formation, along with an analysis of the precipitate morphology. In the near-edge region of these wafers the precipitate number density changes by more than two orders of magnitude over a few millimetres, with a linearly related increase in the number of oxygen atoms lost from solution. Both these parameters are quantitatively correlated with changes in x-ray topographic image contrast, thereby defining useful detection limits for the application of x-ray topography to oxygen precipitation studies under the specific conditions employed.