First principles investigation of hydrogen passivation for selective atomic layer deposition of Pt, Cu, and Au metals

Atomic layer deposition (ALD) is a critical technique in nanofabrication, enabling precise thin-film deposition at the atomic scale. As devices become increasingly smaller and more complex, there is a critical need for deposition techniques that offer atomic-scale precision and spatial selectivity to design intricate patterns and structures. This study investigates the effects of hydrogen passivation on the deposition behaviour of platinum (Pt), copper (Cu), and gold (Au) using first-principles simulations. The density functional theory-based nudge elastic band method was employed to evaluate the energy barriers associated with the initial adsorption reactions of precursors on hydrogen-passivated and bare silicon substrates. Additionally, vibrational frequency calculations were performed to assess the thermodynamics of the reactions analyzed. Results showed that hydrogen passivation significantly increased the energy barriers for Pt, Cu, and Au, effectively hindering the deposition process on passivated surfaces. This passivation acts as a selective masking layer, suggesting favoured deposition on hydrogen-free regions. Gold exhibited the highest potential barrier difference among the metals studied, while platinum demonstrated the most controlled reaction pathways. Overall, the findings highlight the potential of hydrogen passivation in achieving selective ALD for advanced nanoscale device manufacturing.