Characterizing Self-Assembled Monolayer Breakdown in Area-Selective Atomic Layer Deposition.

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Self-assembled monolayers (SAMs) are vital for area-selective atomic layer deposition (AS-ALD) by inhibiting ALD processes.
• Understanding SAM integrity and breakdown during ALD is critical for successful AS-ALD.
• Nucleation on SAM-protected surfaces during ALD and its effect on SAM structure require further investigation.

Purpose of the Study:

• To investigate the structural evolution and crystallinity of octadecyltrichlorosilane (ODTS) SAMs before and after ALD.
• To understand the breakdown mechanisms of ODTS SAMs under ZnO and Al2O3 ALD conditions.
• To explore substrate dependency by comparing Si and sapphire substrates.

Main Methods:

• Utilized synchrotron X-ray techniques to analyze SAM crystallinity and structure.
• Employed electron microscopy to examine SAMs and deposited materials.
• Systematically studied ODTS SAMs exposed to ZnO and Al2O3 ALD on Si and sapphire substrates.

Main Results:

• ODTS SAM crystallinity and structure remained intact until substantial material deposition occurred.
• ZnO ALD resulted in dispersed nanoparticles on ODTS SAMs, while Al2O3 ALD formed a continuous film.
• Similar SAM structural evolution and ALD nucleation were observed on both Si and sapphire substrates.

Conclusions:

• ALD processes influence SAM structure and nucleation behavior, with material-dependent morphologies.
• SAM integrity is maintained until significant deposition, impacting AS-ALD effectiveness.
• The findings provide crucial insights into SAM-ALD interactions for advanced material fabrication.