Photoluminescence of ring-distribution of oxygen precipitates in Czochralski silicon

We have investigated a Czochralski-grown silicon single crystal which contains a ring-shaped distribution of oxidation-induced stacking faults (OSFs) by using a photoluminescence (PL) technique. After two-step annealing at 800°C and 1000°C in N2, dislocation-related D lines have been observed. The observed D lines are due to the dislocations generated from the oxygen precipitates induced by the two-step annealing. The intensities of the D lines in the ring area are weaker than those in the other area. This result coincides with the fact that the density of the oxygen precipitates in the ring area is lower than that in the other area. The strong dependence of the spatial variations in the PL intensity on the penetration depth of the excitation light indicates that the dislocations around the oxygen precipitates are more closely correlated with the ring area in the deeper region from the surface.