Preanneal effect on the ring-shaped distribution of oxygen precipitates in Czochralski-grown silicon

Abstract

An anomalous ring-shaped distribution of oxygen precipitates in Czochralski-grown Si is investigated, using x-ray-diffraction topography and Fourier transform infrared spectroscopy. The appearance of the ring area, corresponding to a region of oxidation-induced stacking faults, strongly depends on the preanneal before the precipitation anneal at 1000 °C. The single precipitation anneal at an elevated temperature without any preanneal maintains the distribution of precipitation nuclei formed at 450 °C during cooling from crystal growth; however, the ring-shaped distribution is not affected by the existence of thermal donors. Therefore, it is concluded that the precipitation nuclei formed at 450 °C do not have any relationship to thermal donors.

Oxygen precipitates distributed around random grain boundaries in a cast-grown multicrystalline silicon crystal

“…Generally, in LSI Si wafers are subjected to two-step annealing to form oxygen precipitates. 16,28,29) Preannealing causes the formation of precipitation nuclei, and postannealing at a higher temperature causes the growth of oxygen precipitates. However, in the mc-Si specimen of this study, both oxygen precipitates and GBs that must be precipitation nuclei have already existed in the as-grown crystal without preannealing.…”

“…11,12) There have been many studies investigating oxygen and oxygen precipitates in sc-Si being used for large-scale integration (LSI) devices. [13][14][15][16][17] Oxygen atoms occupy an interstitial site in the Si crystal, and if the oxygen concentration exceeds the solid solubility, precipitation takes place in the crystal. The oxygen precipitation is used to be enhanced by the presence of nitrogen, carbon, or point defects.…”

X-ray diffraction study of defect distribution in Czochralski grown silicon highly doped by As

“…On the basis of kinematic [1][2][3] and dynamic [4] theories, methods have been worked out that allow us to determine the defect parameters from x-ray diffraction measurements (diffuse scattering, Borrmann effect, etc) [5][6][7]. These techniques were successfully applied in many experimental studies of the structural perfection of single crystals [5][6][7][8][9][10][11][12][13][14][15][16][17][18]; diffuse scattering analysis proved to be useful for the structural characterization of surface layers also [19][20][21][22]. Some problems existing in this area of study, particularly the effect of clusters of large size, were considered in theoretical studies [23][24][25].…”

“…The large size (>1 µm) defects (precipitates, their agglomerates, dislocation loops, stacking faults) were studied by x-ray topography [12,13,17]; in other cases x-ray diffractometry methods (mostly diffuse scattering) were employed [8-11, 14, 15, 17, 18].…”

Non-destructive techniques applied to the detection of oxygen or metallic precipitates in annealed Cz silicon wafers

“…These defects are known to be spread differently along the diameter of the silicon ingot. Frequently, ring-like patterns of microdefects have been observed after crystal growth or after subsequent annealings [5,6] in silicon wafers. Fourier transform infrared spectroscopy (FTIR) has been frequently used to measure [O i ] and to characterize precipitates (by different absorption bands), as have other common techniques such as electron microscopy [7] and defect etching.…”