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Register a new userLarge-scale defect accumulations in Czochralski-grown silicon
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Czochralski-grown silicon crystals were studied by the techniques of the low-angle mid-IR-light scattering and electron-beam-induced current. The large-scale accumulations of electrically-active impurities detected in this material were found to be different in their nature and formation mechanisms from the well-known impurity clouds in a FZ-grown silicon. A classification of the large-scale impurity accumulations in CZ Si is made and point centers constituting them are analyzed in this paper. A model of the large-scale impurity accumulations in CZ-grown Si is also proposed. In addition, the images of the large-scale impurity accumulations obtained by means of the scanning mid-IR-laser microscopy are demonstrated.
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Electrically detected magnetic resonance is used to identify recombination centers in a set of Czochralski grown silicon samples processed to contain strained oxide precipitates with a wide range of densities (~ 1e9 cm-3 to ~ 7e10 cm-3). Measurements reveal that photo-excited charge carriers recombine through Pb0 and Pb1 dangling bonds and comparison to precipitate-free material indicates that these are present at both the sample surface and the oxide precipitates. The electronic recombination rates vary approximately linearly with precipitate density. Additional resonance lines arising from iron-boron and interstitial iron are observed and discussed. Our observations are inconsistent with bolometric heating and interpreted in terms of spin-dependent recombination. Electrically detected magnetic resonance is thus a very powerful and sensitive spectroscopic technique to selectively probe recombination centers in modern photovoltaic device materials.
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