Precipitation and dislocation decoration via extrinsic gettering of Co, Au and Pt by misfit dislocations in Si/Si-2%Ge epitaxy

Abstract

Previous work on the gettering activity of a well defined array of buried interfacial misfit dislocations (MDs) showed that the amount of nickel gettered by MD is dominated by the strong temperature-dependent solubility. Precipitation occurs on or in the immediate vicinity of MDs due to nucleation enhancement by strain effects. High temperature 〈1000°C〉 diffusion of gold resulted in the planar colony precipitates on two {111} planes associated with stacking fault formation. In this contribution, we discuss our continuing research pertaining to cobalt, gold (at low temperature), and platinum gettering by MDs which involves studying the nature of dislocation decoration and impurity precipitation in the Si/Si-2%Ge epitaxial system.All the samples used in this study have a buried Si-2%Ge epitaxial layer of ∼ 2 μm thickness.Co, Au and Pt were deliberately diffused into the wafer. The details of the sample structure and preparation are described in a preceding paper. Two-beam bright field and weak-beam dark field imaging techniques were performed on cross-section TEM specimens.