Fabrication of nanoscale metal paths in oxide thin layers by noble-gas ion beams

We investigated the fabrication process of a nanostructure with alumina insulator layer and nanoscale Cu paths punching through an alumina layer inserted between magnetic multilayers. Ion-beam-assisted oxidation was applied to an AlCu layer, where ion beams with three kinds of noble gases of different mass, Ne, Ar and Xe, were compared. The heavy gas overcame the trade-off between the increasing purity of nanoscale Cu paths and the decreasing oxygen defects of the alumina. It is considered that the high mobility of surface atoms in the AlCu layer brought about by the heavy-gas ion beam promotes segregation of alumina and Cu.