The Role of Oxygen on the Stability of Gettering of Metals to Cavities in Silicon

Abstract

The effect of oxygen implanted into epitaxial Si layers on the ability to getter Au to nanocavities, previously formed by H implantation and annealing, has been studied by Rutherford backscattering, transmission electron microscopy, and secondary ion mass spectrometry. We demonstrate that oxygen is gettered to cavities during extended annealing at 950 °C. Furthermore, the arrival of oxygen at cavities is not only shown to inhibit subsequent attempts to getter Au to cavities, but also to eject chemisorbed Au from the cavity walls. Similar behavior is observed in Czochralski Si, where the source of oxygen is within the Si itself.