Copper Precipitation at the Silicon-Silicon-Dioxide Interface: Role of Oxygen

Abstract

Copper contamination is often the origin of the lifetime degradation during processing of solar cells. Its behaviour during oxidation is investigated in this paper. It is shown by analytical transmission electron microscopy that the thermal oxidation of Czochralski silicon induces at the silicon-silicon-dioxide interface the precipitation of large copper colonies associated with oxidation-stacking-fault (OSF) Frank partial dislocations decorated with oxygen. The precipitation process is different in float-zone silicon where the Frank partial dislocations bounding the OSFs are themselves nucleation sites for copper precipitates.