Abstract:
The photoluminescence related to dislocation formation in silicon wafers subjected to the bending mode of central symmetry by a circular male die, which has never been used for this purpose before, is investigated. An original technique whose efficiency was very recently demonstrated in the bending experiments on silicon wafers allows one to simultaneously determine the mechanical stress on the stretched and compressed sides of a wafer by the shift of the $520.5$ cm$^{-1}$ band in the Raman spectra. Plastic deformation of the wafer under mechanical loading is carried out at $T = 700^\circ$C for one hour. It is shown that all four known dislocation luminescence bands (lines $D1$–$D4$) and extended structural defects $\{113\}$ appear on the stretched side of the wafer outside the central part. On the compressed side of the wafer outside the central part, lines $D3$ and $D4$ are clearly visible, as well as the edge luminescence line, but lines $D1$ and $D2$ are absent. When approaching the center of the wafer the $D3$ and $D4$ lines prevail on the stretched and compressed sides with residual deformation, and the $D4$ line dominates in the very center. In this way, some prominent changes in the dislocation luminescence of plastically deformed silicon wafers under tensile and compressive stresses produced by the bending mode of central symmetry are evident.
Keywords:silicon, bending mode of central symmetry, plastic deformation, photoluminescence.
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