Precise XPS depth profile of soda-lime-silica glass using C60 ion beam

Ar ion sputtering is one of the most accepted techniques for depth profiling in practical X-ray photoelectron spectroscopy (XPS) analysis, while this technique is known to be inadequate for quantitative analysis of glass including mobile ions such as soda-lime-silica glass. For the precise depth profiling on XPS depth analysis, three methods, (i) coating of conductive thin film on glass surface, (ii) sample cooling at the temperature of −130 °C and (iii) buckminsterfullerene (C₆₀) ion sputtering, were investigated to suppress the migration of mobile ions in glass. In our best knowledge, it is the first time to succeed the precise XPS depth analysis of soda-lime-silica glass (70.4SiO₂, 0.9Al₂O₃, 7.3MgO, 7.8CaO, 13.6Na₂O in mol%) without compositional change by using C₆₀ ion sputtering. The precise analysis revealed that the ion implantation during Ar ion sputtering principally resulted in the compositional change due to the migration of mobile ions.