Electron-beam induced deposition of high-purity copper nanostructures is desirable for nanoscale rapid prototyping, interconnection of chemically synthesized structures, and integrated circuit editing. However, metalorganic, gas-phase precursors for copper introduce high levels of carbon contamination. Here we demonstrate electron beam induced deposition of high-purity copper nanostructures from aqueous solutions of copper sulfate. The addition of sulfuric acid eliminates oxygen contamination from the deposit and produces a deposit with ~95 at% copper. The addition of sodium dodecyl sulfate (SDS), Triton X-100, or polyethylene glycole (PEG) improves pattern resolution and controls deposit morphology but leads to slightly reduced purity. High resolution nested lines with a 100 nm pitch are obtained from CuSO4–H2SO4–SDS–H2O. Higher aspect ratios (~1:1) with reduced line edge roughness and unintended deposition are obtained from CuSO4–H2SO4–PEG–H2O. Evidence for radiation-chemical deposition mechanisms was observed, including deposition efficiency as high as 1.4 primary electrons/Cu atom.
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This material is based upon work supported by the National Science Foundation under Grant Numbers CMMI-1125998, CMMI-1538650, and ECCS-1542164.
Supplementary material for this article is available online.
Esfandiarpour, Samaneh; Boehme, Lindsay; and Hastings, J. Todd, "Focused Electron Beam Induced Deposition of Copper with High Resolution and Purity from Aqueous Solutions" (2017). Electrical and Computer Engineering Faculty Publications. 32.