Conductive nanostructure fabrication by focused ion beam direct-writing of silver nanoparticles

A focused ion beam has been used to directly pattern thin films of organometallic silver nanoparticles down to a resolution of 100nm. The unexposed regions were washed in hexane leaving the desired pattern, and subsequent annealing formed conductive, metallic features. Multiple-layer structures were also fabricated by spin-coating and exposing additional films of silver nanoparticles on top of already patterned structures. The sensitivity of the nanoparticles to 30keVGa+ ions was measured to be approximately 5μC∕cm2. Using this technique test structures were fabricated in two and three dimensions with resistivities as low as 288μΩcm and 13μΩcm for single- and multiple-layer structures, respectively, as compared to a value of 1.589μΩcm for bulk silver. To our knowledge, this is the highest demonstrated throughput for any electron or ion beam direct-write process utilizing metal-organic precursors.