In recent years, area‐selective atomic layer deposition (AS‐ALD) has attracted increasing interest for its applications in back‐end interconnect processes, and selective deposition of Al2O3is of particular interest because Al2O3can serve as an etch hard mask. However, Al2O3is one of the most difficult ALD systems to block. In this work, a strategy is presented to enhance the blocking ability of dodecanethiol (DDT) self‐assembled monolayers (SAMs) against Al2O3ALD. It is shown that by conducting DDT deposition on a slightly oxidized Cu surface, which is mainly composed of Cu2O, rather than on a freshly acid‐etched Cu surface, which mainly consists of metallic Cu, the quality of the DDT SAM can be improved. It is further shown that the DDT SAMs formed on Cu2O‐covered Cu substrates are about 3–4 times more effective in blocking Al2O3than that on acid‐etched Cu surfaces when ALD is performed under subsaturation condition. However, as the Cu oxidation process continues, CuO is formed and the blocking ability of DDT degrades. Finally, selective Al2O3deposition on DDT‐treated Cu/low‐
Elucidating metal oxide growth mechanisms is essential for precisely designing and fabricating nanostructured oxides with broad applications in energy and electronics. However, current epitaxial oxide growth methods are based on macroscopic empirical knowledge, lacking fundamental guidance at the nanoscale. Using correlated in situ environmental transmission electron microscopy, statistically-validated quantitative analysis, and density functional theory calculations, we show epitaxial Cu2O nano-island growth on Cu is layer-by-layer along Cu2O(110) planes, regardless of substrate orientation, contradicting classical models that predict multi-layer growth parallel to substrate surfaces. Growth kinetics show cubic relationships with time, indicating individual oxide monolayers follow Frank-van der Merwe growth whereas oxide islands follow Stranski-Krastanov growth. Cu sources for island growth transition from step edges to bulk substrates during oxidation, contrasting with classical corrosion theories which assume subsurface sources predominate. Our results resolve alternative epitaxial island growth mechanisms, improving the understanding of oxidation dynamics critical for advanced manufacturing at the nanoscale.
more » « less- Award ID(s):
- 1905647
- PAR ID:
- 10227928
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 12
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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