Purification of platinum and gold structures after electron-beam-induced deposition

The technique of electron-beam-induced deposition (EBID), when performed with organic precursors, typically results in relatively low metal content due to the partial decomposition of the organic precursor, leaving carbon-rich remnants in the deposition. Here we describe a method applied to noble-metal structures deposited using EBID, consisting of a post-treatment step of heating in a reactive atmosphere of oxygen, whereby the amount of carbon in the structure is strongly reduced. As a result, we have been able to increase the purity of platinum deposits from 15 at.% to nearly 70 at.%, and gold similarly from 8 at.% to nearly 60 at.%. The resistivity of these structures has also been improved by up to four orders of magnitude, to achieve (1.4 +/- 0.2) x 10(4) mu Omega cm in the case of platinum.