Authors:	M. Van Daele, M. Griffiths, A. Raza, S. Matthias, F. Eduardo, J.-Y. Feng, R. Ramachandran, S. Clemmen, R. Baets, S. Barry, C. Detavernier , J. Dendooven
Title:	Plasma-enhanced atomic layer deposition of nanostructured gold near room temperature
Format:	International Journal
Publication date:	9/2019
Journal/Conference/Book:	ACS Appl. Mater. Interfaces
Volume(Issue):	40(11) p.37229-37238
DOI:	10.1021/acsami.9b10848
Citations:	13 (Dimensions.ai - last update: 24/11/2024) 11 (OpenCitations - last update: 27/6/2024) Look up on Google Scholar
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Abstract

A plasma-enhanced atomic layer deposition (PE-ALD) process to deposit metallic gold is reported, using the previously reported Me3Au(PMe3) precursor with H2 plasma as the reactant. The process has a deposition window from 50 to 120 °C with a growth rate of 0.030 ± 0.002 nm per cycle on gold seed layers, and it shows saturating behavior for both the precursor and reactant exposure. X-ray photoelectron spectroscopy measurements show that the gold films deposited at 120 °C are of higher purity than the previously reported ones (<1 at. % carbon and oxygen impurities and <0.1 at. % phosphorous). A low resistivity value was obtained (5.9 ± 0.3 μΩ cm), and X-ray diffraction measurements confirm that films deposited at 50 and 120 °C are polycrystalline. The process forms gold nanoparticles on oxide surfaces, which coalesce into wormlike nanostructures during deposition. Nanostructures grown at 120 °C are evaluated as substrates for free-space surface-enhanced Raman spectroscopy (SERS) and exhibit an excellent enhancement factor that is without optimization, only one order of magnitude weaker than state-of-the-art gold nanodome substrates. The reported gold PE-ALD process therefore offers a deposition method to create SERS substrates that are template-free and does not require lithography. Using this process, it is possible to deposit nanostructured gold layers at low temperatures on complex three-dimensional (3D) substrates, opening up opportunities for the application of gold ALD in flexible electronics, heterogeneous catalysis, or the preparation of 3D SERS substrates