Electrical testing of gold nanostructures by conducting atomic force microscopy

We devised a method for the reliable electrical testing of nanoscale wire a rrays using conducting probe atomic force microscopy (AFM) in ambient condi tions. A key requirement of this approach is the formation of highly reprod ucible electrical contacts between the conducting tip and the sample. We di scuss the basic mechanical and electrical criteria of nanocontacts and deri ve a force-controlled protocol for the formation of low-ohmic contacts. Tip s sputter coated with platinum provided the mechanical stability for both t apping-mode imaging and the formation of low-ohmic contacts on gold samples . Nanostructures on the sample were identified by topographic imaging and s ubsequently probed using the AFM tip as a mobile electrode. We measured res istivities in arrays of nanowires or local potentials of wires within elect rical circuits, and detected electrical failures, thermal gradients, and sm all geometrical variations. The ability of this instrument to address elect rical characteristics with high spatial resolution makes it a powerful tool fur lithography developments and on-chip monitoring of nanoscale circuits. (C) 2000 American Vacuum Society. [S0734-211X(00)03103-6].