Fabrication of nanometer-sized magnetic structures using e-beam patterned deposition masks

We report on the development of a novel technique designed to study dimensional effects in sputter-deposited magnetic materials and multilayer nanostructures without the need for post-deposition patterning. Wires with widths ranging from 40 to 1000 nm have been deposited on Si wafer substrates through a deposition mask fabricated by e-beam lithography. A bilevel resist masking scheme allows smooth, near vertical sidewall profiles, and the resulting structures can be exposed using a simple lift-off process. This process was used to fabricate test structures of Fe, Cu, and Co which were characterized by scanning electron microscopy, atomic force microscopy, and ac resistivity measurements from 3 to 300 K. While the wire structures are geometrically well defined, transport measurements reveal high crystalline defect densities which must be eliminated to fabricate low-dimensional magnetoresistive structures.