Deep-level photoluminescence due to dislocations and oxygen precipitates in multicrystalline Si

Abstract

We have demonstrated the presence of a dislocation-related component and a component due to oxygen precipitates in a broad deep-level photoluminescence (PL) band in multicrystalline Si at room temperature. In PL intensity mapping, the lower-energy side of the deep-level PL band at about 0.79 eV appeared as a dark line along a small-angle grain boundary (SA-GB) surrounded by a bright band on either side, while the higher-energy side at about 0.87 eV as a bright line along the SA-GB. These intensity variations agree with the low-temperature PL intensity patterns for well-established dislocation-related lines of D1/D2 and those for oxygen precipitates, respectively. These patterns were observed around SA-GBs with a misorientation angle of 1–2°, and were assumed to be due to the distribution of secondary defects or impurities trapped by the strain field around dislocation clusters forming SA-GBs and that of preferential oxygen precipitation on the dislocations. A spectral component associated with the D3/D4 lines was also extractable from the deep-level PL at about 0.94 eV. The intensity increased on SA-GBs with the angle of <1°, where oxygen precipitation did not occur. This corresponds to the generally accepted idea that the D3/D4 lines are related to the intrinsic nature of dislocations.