The influence of oxygen on the minority carrier lifetime of silicon is reported. Bulk annealed, oxygen‐rich crystals subsequently sliced into wafers show lifetime degradation with annealing time. Silicon oxide precipitates and punched out dislocation loops induced during annealing are identified as electrically active defects responsible for the observed lifetime degradation. Increase in device yields (diodes) and improved lifetime in epitaxial films obtained with oxygen‐rich wafers as substrates are a result of “intrinsic gettering” of oxygen‐rich wafers. It is shown that “external gettering” cannot improve minority carrier lifetime in silicon wafers if during processing “intrinsic gettering” is activated. It is also shown that “external gettering” such as impact sound stressing (ISS) is very effective in improving lifetime for wafers not containing “intrinsic gettering” sources.

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)~) X-ray interference fringes observed in X-ray topographs of silicon crystals bombarded with high energy ions (dose > 10'5 ions/cm2) are described. The X-ray fringes are used to analyze the deformation state of the crystal. It is shown that the bombarded crystal is a special kind of bicrystal composed of a thick perfect bulk crystal topped by a thinpractically perfect layer crystal. Both crystals have the same crystallographic orientation and the same lattice constant but are separated by a small rigid body displacement. Contrast and geometry of the observed X-ray patterns agree with the theoretical patterns calculated by Bonse and Hart [I] on the basis of a layer/bulk bicrystal model, and are also supported through transmission electron microscopy results. The ion range calculated from the interference fringes is in good agreement with the experimentally determined range. Rontgeninterferenzen, beobachtet in Rontgentopogrammen von

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Diffusion-induced dislocations in silicon have been studied by x-ray diffraction microscopy. Lines lying in a (001) diffusion plane forming rectangular arrays have been identified as edge dislocations in [11̄0] and [110] directions with Burgers vectors ½ [110] and ½ [11̄0] and (001) glide plane.