Detection of sputtered neutral atoms by nonresonant multiphoton ionization

A nonresonant multiphoton ionization method was applied for the detection of sputtered neutrals using a time-of-flight mass spectrometer. The preliminary results for Cu, Ni and Cu-Ni alloy samples are reported from the viewpoint of a semiquantitative surface analysis. Photoions from pure elements were a reflection of their sputtering yield ratios. The estimated composition of an alloy during sputtering at room temperature is almost the same as that of bulk. On the other hand, anomalous copper-enriched flux was detected at 800 K, and the result was explained by the enhanced segregation and diffusion of copper through the ion-damaged surface layer.