Extrinsic Gettering with Epitaxial Misfit Dislocations

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Abstract
New results are presented on Ge doped Si epitaxial layers which contain interfacial misfit dislocations. Microscopic and chemical analyses showed the preferential gettering of several metallic species (Au, Cu, Ni, and Fe) at the misfit dislocations with semiquantitative correlation between dislocation density and the captured impurity concentration. Wafer curvature was measured and shown to be less than that for typical Si3N4and SiO2layers used in IC fabrication. The reduction of Schottky diode leakage current has been clearly demonstrated and attributed to gettering of residual impurities, as well as signifying that, the active surface device region is not deleteriously affected by spurious defect reactions at the buried epitaxial interface.