Carbene-Derived Small Molecule Inhibitors for Area-Selective Atomic Layer Depositions

Area-selective atomic layer deposition (AS-ALD) is a self-aligned thin-film deposition method with the potential to overcome key challenges in semiconductor miniaturization and energy-efficient manufacturing. A key component of AS-ALD is the deposition growth resist that inhibits ALD. Among these, small molecule inhibitors (SMIs) have emerged as a promising alternative to traditional polymer and self-assembled monolayer (SAM) resists, offering higher spatial resolution and broader compatibility with diverse substrates and ALD chemistries.

In this study, we present a novel carbene-based SMI to evaluate its ability to inhibit Al₂O₃ and TiO₂ growth on silicon. We compare its mechanism to that of SAMs and validate the SMI layer’s stability and performance using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). In addition, we demonstrate the patterning of the SMI resist and the area-selective deposition of TiO₂ via contact printing techniques.

The results show that deposition selectivity can be tuned through simple SMI surface reactions. The developed monolayers exhibit inhibition performance comparable to the conventional resists such as hydrogen-terminated silicon and SAMs, while offering improved stability under ambient conditions. Depth profile analysis suggests that the growth of ALD film follows a different mechanism compared to the defect-driven mechanism that is generally observed on SAMs. This work contributes to advancing bottom-up semiconductor fabrication strategies, which are critical for future electronic, photonic, and quantum technologies.