Papers by Keyword: Recombination Activity

Abstract: Light microscopy, electron backscatter diffraction and transmission electron microscopy is employed to investigate dislocation structure and impurity precipitation in commonly occurring dislocation clusters as observed on defect-etched directionally solidified multicrystalline silicon wafers. The investigation shows that poligonised structures consist of parallel mostly similar, straight, well-ordered dislocations, with minimal contact-interaction and no evidence of precipitate decoration. On the other hand, disordered structures consist of various dislocation types, with interactions being common. Decoration of dislocations by second phase particles is observed in some cases. Enhanced recombination activity of dislocations may therefore be a result of dislocation interaction forming tangles, microscopic kinks and jogs, which can serve as heterogeneous nucleation sites that enhance metallic decoration.

Abstract: We report on a light-beam-induced current (LBIC)-analysis of metal silicide defects arising from co-precipitation of copper and nickel in Cz-silicon-bicrystals produced by wafer direct bonding. Large colonies of silicide precipitates in the one wafer emerging from undisturbed growth from few nucleation sites were observed in different orientations with respect to the surface which correspond to Si {110} planes. From this, the colonies formed during copper-nickel co-precipitation reveal the same attributes as those colonies typical for copper precipitation in the absence of nickel. Oxygen related defects associated with a higher defect distribution in the other wafer were characterized by means of high resolution Transmission Electron Microscopy (TEM) and their temperature dependent LBIC signal.

Abstract: Silicon samples doped with gallium and intentionally contaminated with iron have been studied by means of electron beam current (EBIC), capacitance voltage (CV) and deep level transient spectroscopy (DLTS) methods. Reverse bias anneal (RBA) treatments at temperatures of 390-420K were used to move hydrogen and dissolved iron atoms away from the surface. A new procedure was developed to find dislocations lying on desirable depth from the surface and to analyze the depth distribution of their recombination contrast. Iron contaminated dislocations do not noticeably change their recombination activity when kept in an electrical field as high as 104 V/cm at 420K for several hours. This implies a tight binding of iron atoms at dislocations. The binding energy of iron with dislocations seems to be much larger than for Fe-Ga and H-Ga pairs. Low temperature hydrogenation of iron contaminated dislocations does not produce any passivation effect. In opposite, the recombination activity of the dislocations significantly increases after RBA treatment.