PREFERENTIAL SPUTTERING IN GOLD-NICKEL AND GOLD-COPPER ALLOYS

The preferential sputtering of three alloys of gold and nickel and five alloys of gold and copper is studied. Binary alloys containing 6-26 at. % nickel and 6-57 at. % copper were used. Samples were scribed in situ to avoid the complication of a surface oxide film. For Ni/Au with an ion energy of 1 keV, the gold was sputtered preferentially leaving a nickel-enriched surface. For the 6% alloy the amount of enrichment was somewhat less than is predicted from pure element sputter yields, whereas for the other two alloys the enrichment is slightly higher than predicted. The thickness of the altered layer appears to be in the 50-75A range. For Cu/Au, very little preferential sputtering was observed.