Extrinsic gettering via the controlled introduction of misfit dislocations

As an alternative to existing gettering techniques, extrinsic gettering by misfit dislocations is described and gettering efficiency evaluated. Uniform arrays of misfit dislocations were generated at epitaxial Si interfaces by incorporation of 0.1–1% of Ge. The dislocations were shown to be confined to the interface by means of optical and electron microscopies. The misfit dislocations were used as extrinsic gettering sinks for metallic impurities deliberately introduced and diffused towards the dislocations. Transmission electron microscopy and secondary ion mass spectrometry analyses showed the preferential precipitation of Cu and Au at the misfit dislocations.