DNA origami are of potential use in positioning non-DNA components for fabrication of plasmonic, magnetic, or nanoelectronic structures. Several recent studies of the tolerance of DNA origami to lithographic processing steps have found surprising stability of this biomolecule when heated in the absence of water. We find that heating DNA origami to 1000 C on silicon drives carbon from the DNA several nanometers into the silicon, creating silicon carbide replicas of the origami. DNA origami with dimensions of 2 x 70 x 90 nm adhered to cationic monolayers on silicon surfaces and were capped with 20 nm of silicon oxide via chemical vapor deposition before rapid thermal processing at 1000 C for 90 seconds. After brief HF etching, silicon chips normally form a hydrophobic H-terminated monolayer, but the processed chips remained hydrophilic even after 20 minutes of etching, indicating an alteration in their surface chemistry. Rectangular features the same size as the DNA origami templates were observed by AFM and SEM. Depth profiling with X-ray photoelectron spectrometry revealed carbon at binding energies consistent with silicon carbide. We hope to report on the fate of some other elements in the origami, particularly the phosphorous atoms, which are n-type dopants in silicon or silicon carbide.

Pyrolysis of DNA origami drives carbon atoms into the substrate forming silicon carbide replicas

253rd National Meeting (2017)

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