Development of Water Cluster Ion Beam Source and Its Application

Abstract

Water cluster ion beam source was developed. Multiply-charged water clusters were generated by ambient or vacuum electrospray. Cluster ions (represented as [(H 2 O) 90,000 ＋100H)] 100＋) impact the solid sample under vacuum with kinetic energy of 10 6 eV. Supersonic collisions of water droplets with the surface lead to the atomic/molecular level sample desorption, high-e‹ciency ionization, and non-selective surface etching without sample modiˆcation. By this technique, inorganic materials and organic materials can be etched with etching rates of a few and 10 nm/min, respectively. This technique was successfully applied to the interface analysis for CuO/ Cu.