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.

Micrometer-Scale Deep-Level Spectral Photoluminescence From Dislocations in Multicrystalline Silicon

“…On the other hand, the doublet D3/D4 was believed to represent the intrinsic nature of dislocations [8], [15]. This was confirmed recently by Tajima et al [1], [20], who employed micro-PL (μPL) spectroscopy with a high spatial resolution to examine the distribution of D lines around the sub-GBs, finding that D1/D2 were distributed around the sub-GBs, whereas D3/D4 were located directly at the sub-GBs.…”

Distribution of radiative crystal imperfections through a silicon ingot

“…They also observed pairwise similarity between D1/D2 and D3/D4 regarding their spatial distribution. Oxygen precipitates has also been found to be a possible origin of the D-lines by Pizzini et al 10 and Tajima et al 11 Arguriov 12 proposed D1 and D2 to be generated by transitions between one-dimensional bands on 60…”

Photoluminescence Analysis of Oxygen Precipitation around Small-Angle Grain Boundaries in Multicrystalline Silicon Wafers

“…In contrast, the intensity of the deep-level emissions became strong around SA-GBs. We reported that deep-level emissions at room temperature consist of multiple bands [7]. One deep-level PL labeled D b around 0.87 eV was ascribable to oxygen precipitates.…”

“…The intensity of the D b band became higher on SA-GBs, reecting that these grain boundaries acted as preferential precipitation sites for oxygen [7]. Another deep-level PL labeled D a1 around 0.79 eV, which was attributable to secondary defects or impurities attracted by a strain eld around SA-GBs, appeared as bright bands surrounding SA-GBs [7]. Objectives of the present study were to investigate the relationship between these deep-level emissions and the density of SA-GBs and to identify the origin of the D b band emission.…”

“…One deep-level PL labeled D b around 0.87 eV was ascribable to oxygen precipitates. The intensity of the D b band became higher on SA-GBs, reecting that these grain boundaries acted as preferential precipitation sites for oxygen [7]. Another deep-level PL labeled D a1 around 0.79 eV, which was attributable to secondary defects or impurities attracted by a strain eld around SA-GBs, appeared as bright bands surrounding SA-GBs [7].…”