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In area-selective processes, such as area-selective atomic layer deposition (AS-ALD), there is renewed interest in designing surface modification schemes allowing to tune the reactivity of the nongrowth (NG) substrates. Many efforts are directed toward small molecule inhibitors or atomic layers, which would modify selected surfaces to delay nucleation and provide NG properties in the target AS-ALD processes allowing for the manufacturing of smaller sized features than those produced with alternative approaches. Bromine termination of silicon surfaces, specifically Si(100) and Si(111), is evaluated as a potential pathway to design NG substrates for the deposition of metal oxides, and TiO2 (from cycles of sequential exposures of tetrakis-dimethylamido-titanium and water) is tested as a prototypical deposition material. Nucleation delays on the surfaces produced are comparable to those on H-terminated silicon that is commonly used as an NG substrate. However, the silicon surfaces produced by bromination are more stable, and even oxidation does not change their chemical reactivity substantially. Once the NG surface is eventually overgrown after a large number of ALD cycles, bromine remains at the interface between silicon and TiO2. The NG behavior of different crystal faces of silicon appears to be similar, albeit not identical, despite different arrangements and coverage of bromine atoms.
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Inhibition of atomic layer deposition of TiO2 by functionalizing silicon surface with 4-fluorophenylboronic acid
As the size of the components in electronic devices decreases, new approaches and chemical modification schemes are needed to produce nanometer-size features with bottom-up manufacturing. Organic monolayers can be used as effective resists to block the growth of materials on non-growth substrates in area-selective deposition methods. However, choosing the appropriate surface modification requires knowledge of the corresponding chemistry and also a detailed investigation of the behavior of the functionalized surface in realistic deposition schemes. This study aims to investigate the chemistry of boronic acids that can be used to prepare such non-growth areas on elemental semiconductors. 4-Fluorophenylboronic acid is used as a model to investigate the possibility to utilize the Si(100) surface functionalized with this compound as a non-growth substrate in a titanium dioxide (TiO2) deposition scheme based on sequential doses of tetrakis(dimethylamido)titanium and water. A combination of X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry allows for a better understanding of the process. The resulting surface is shown to be an effective non-growth area to TiO2 deposition when compared to currently used H-terminated silicon surfaces but to exhibit much higher stability in ambient conditions.
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- PAR ID:
- 10545246
- Publisher / Repository:
- AIP Publishing
- Date Published:
- Journal Name:
- Journal of Vacuum Science & Technology A
- Volume:
- 42
- Issue:
- 3
- ISSN:
- 0734-2101
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1116/6.0003316
