Focused ion beam etching of resist Ni multilayer films and applications to metal island structure formation

A new method to fabricate single-electron tunneling. structures with magnetic materials using focused ion beam (FIB) sputtering and lithography techniques is proposed. By using this method, a small metal island with a size comparable to or smaller than the FIB diameter, connected with source and drain electrodes via tunnel junctions, can be fabricated. In the present article, some important parameters in this method, such as sputtering yields of the photoresist (AZ 1350) and nickel (Ni) layers, were measured and cross-sectional images of the grooves delineated on a AZ/Ni/SiO2 substrate, which is the basic structure in this method, were observed. At present, a 0.4-mu m-wide groove is obtained. However, this width is limited not by a fundamental process but by noise in the scan signal and stage vibration. (C) 1998 American Vacuum Society.