A study of defects generated in Czochralski-grown Si during two-step annealing

Abstract

A variety of oxygen-related micro-defects (spherical and octahedral precipitates, their agglomerations, dislocations and dislocation loops) with dimensions in the range 0.1-100 mu m were revealed using X-ray topography and transmission electron microscopy after two-step annealing of Czochralski-grown silicon. The defects are distributed in a non-uniform way across the samples with the gradient of their density normal to the crystal surface.

Characterization of defects in mono-like silicon for photovoltaic applications using X-ray Bragg diffraction imaging

“…Many precipitates are present in monolike crystals. Within the Cz-grown seeds, the thermal process can lead the oxygen, already present in the matrix, to form SiO 2 precipitates (see for instance Bialas & Hesse, 1969;Lefeld-Sosnowska et al, 1995;Can Cui et al, 2008). The SiO 2 forms at high temperature (973-1073 K), and its thermal dilation is about five times smaller than that of Si.…”

Dislocations Generated in Si Annealed under Normal or High Pressure

“…They were generated in the crystal after 10 h of annealing in the second step of the process when the oxygen precipitates were already formed. The samples cut from the same as-grown crystal, annealed up to 8 h at 1423 K do not show any dislocations [9]. The most important dislocation sources activated in Cz-Si during annealing are the large precipitates, around which the dislocation loops are emitted by punching.…”

“…The dislocation sets generated by other than punching mechanism were revealed in the crystals by large oxygen precipitates, detected on topographs [9], and only surface dislocations, emanating from the crystal edge in the sample without such large precipitates, were seen in the X-ray topographs.…”

X-ray study of dopant state in highly doped semiconductor single crystals

“…These methods were applied successfully for the study of doped crystals after postgrowth heat treatment when generating defects in them were well pronounced [5][6][7][8]. In the as-grown state, when there are a few defects or they have a very fine size and weakly deform crystal lattice, the standard diffraction methods are not sufficiently sensitive.…”