Conducting AFM studies of metal surface contact resistance for NEMS switches

Surface contact resistances of 12 electronic metals on tungsten used as structural metal were studied. Ultra Sharp conductive Si AFM tip was used to measure current versus voltage (I-V) characteristics as well as for imaging the change in the metal surface morphology after subsequent I-Vs. The structural metal was DC sputtered and the electronic metals for improving the contact resistance were deposited by lift-off technique. The change in the contact resistance and surface morphology due to anodic oxidation and/or alloying and other effects were studied using the AFM imaging as well as studying the I-Vs. This is the first study showing the evolution of surface morphology and electrical properties as a function of switching cycles.