Low-pressure plasma cleaning of Au and PtIr noble metal surfaces

The effect of low-pressure hydrogen and oxygen plasma cleaning of Au and PtIr was investigated by X-ray photoelectron spectroscopy. Hydrocarbon contamination was efficiently removed by hydrogen and oxygen plasma. Hydrogen plasma additionally reduces oxygen compounds, especially metal oxides, while oxygen plasma results in the formation of a surface layer of Au₂O₃ and PtO, respectively. Both noble metal oxides are unstable and decompose with time. The decomposition of metal oxides occurs in parallel with the recontamination of the surface. Metal oxides can be removed completely for Au and partially for PtIr by an additional cleaning with hydrogen plasma. Hydrogen plasma treatment is very promising for noble metal surface cleaning.