Electron-Beam-Induced Deposition of Platinum from a Liquid Precursor

We demonstrate here the first focused electron-beam-induced deposition (EBID) of nanostructures using a liquid precursor. We have deposited sub-50 nm platinum (Pt) wires and dots from a dilute, aqueous solution of chloroplatinic acid. Existing EBID processes rely on the electron-beam stimulated decomposition of gaseous precursors; as a result, the deposits are highly contaminated (up to 75 at. % carbon or 60 at. % phosphorus for Pt processes). In contrast, we show that deposition of platinum by electron-beam reduction of platinum ions from solution leads to high-purity deposits (similar to 10 at. % chlorine contamination) at rates at least ten times higher than those obtained with other platinum precursors. Liquid-phase EBID offers a new route to deterministic, three-dimensional, nanometer-scale structures composed of multiple materials without complex multistep processing. Thus, it may prove important for prototyping and low-volume production of nanoscale devices and for repair and modification of nanoscale masks and templates used in high-volume production.