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Published on: June 16, 2014
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Relation between Reactive Surface Sites and Precursor Choice for Area-Selective Atomic Layer Deposition Using Small
Marc J M Merkx1, Athanasios Angelidis1, Alfredo Mameli2
1Department of Applied Physics, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands.
Summary
Small molecule inhibitors (SMIs) are crucial for area-selective atomic layer deposition (ALD). This study reveals that chemical passivation, alongside steric shielding, is essential for effective precursor blocking in ALD processes.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Area-selective atomic layer deposition (ALD) utilizes small molecule inhibitors (SMIs) for bottom-up fabrication.
- Challenges exist in completely blocking precursor adsorption due to SMI size and short exposure times.
Purpose of the Study:
- To determine if steric shielding alone is sufficient for effective precursor blocking in area-selective ALD.
- To investigate the necessity of chemical passivation in conjunction with steric shielding.
- To understand why certain ALD precursors are more difficult to block than others.
Main Methods:
- Investigated the blocking efficacy of acetylacetone (Hacac) as an inhibitor.
- Studied the adsorption behavior of aluminum precursors: trimethylaluminum (TMA), dimethylaluminum isopropoxide (DMAI), and tris(dimethylamino)aluminum (TDMAA).
- Evaluated precursor blocking by comparing steric shielding with chemical passivation strategies.
Main Results:
- DMAI and TDMAA were more effectively blocked than TMA.
- DMAI and TDMAA adsorb on the same surface sites as Hacac, facilitating blocking.
- TMA exhibits reactivity with additional surface sites, making it harder to block.
- Chemical passivation plays a critical role in enhancing precursor blocking.
Conclusions:
- Effective precursor blocking in area-selective ALD requires both steric shielding and chemical passivation.
- The reactivity of the precursor with surface groups on non-growth areas is key to successful blocking.
- Understanding precursor-surface interactions is vital for optimizing area-selective ALD processes.
