TEMPERATURE DEPENDENCE OF AG/CU SPUTTERING RATIO FOR EUTECTIC

The relative sputtering rates of Ag and Cu from the Ag/Cu eutectic (60% Ag-40% Cu by atoms) were measured by means of the spectroscopic emission technique. The targets were bombarded by 100-eV Ar ions for target temperatures in the range of 80°to 285°C. At low target temperatures, the Ag and Cu sputtering yields vary with time of sputtering according to a simple sputtering model. However, at the higher temperatures surprisingly large differences were observed which could not be explained by a simple model. For example, Ag/Cu sputtering ratio variations greater than a factor of 10 were observed. After prolonged sputtering in the high-temperature range, a thick surface layer (∼1 μ) developed which was highly enriched in Cu. A model based on surface diffusion of Ag on Cu is proposed to explain the results. © 1969 The American Institute of Physics.