Evaluating Depth Distributions of Dislocations in Silicon Wafers Using Micro-Photoluminescence Excitation Spectroscopy

Combining micro-photoluminescence spectroscopy and photoluminescence excitation spectroscopy, we are able to observe the evolution of the luminescence spectra from crystalline silicon wafers under various excitation wavelengths. By interpreting the relative change of the luminescence spectra, we can detect and examine the distributions of the dislocations, as well as of the defects and impurities trapped around them, segregated at different depths below the wafer surface. We show that in multicrystalline silicon wafers, the dislocations and the trapped defects and impurities, formed during the ingot growth and cooling, are distributed throughout the wafer thickness, whereas those generated in monocrystalline wafers by a post-diffusion thermal treatment are located near the wafer surface.