Build-up and degradation of small-molecule inhibitor layers in area-selective atomic layer deposition revealed by density functional theory

• Applicant: Professor Dr. Ralf Tonner-Zech
• Subject Area: Theoretical Chemistry: Molecules, Materials, Surfaces
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 535639476

Area-selective atomic layer deposition is an emerging bottom-up approach in semiconductor manufacturing. It relies on precursor molecules initiating growth on one surface while a second surface stays clean. This is mainly achieved by layers of growth-inhibiting molecules on the second surface. While self-assembled monolayers (SAMs) have been the first systems to be studied, smaller molecules (SMIs) are now in the research focus due to more favorable properties (e.g., volatility, selectivity). The processes of surface inhibition and the growth by atomic layer deposition are dominated by surface chemistry that we and others could reveal for several systems in the past. The most pressing question is how the inhibiting layer can be kept stable and, thus, how decomposition can be prevented. This is important since selectivity is only achieved with an intact inhibitor layer. Since experimental investigations are complicated in these systems, computational surface chemistry approaches with density functional theory applying periodic boundary conditions can reveal the major mechanisms. This project thus aims to provide a comprehensive overview of decomposition pathways from first principles methods. We selected three systems important for area-selective atomic layer deposition as test cases. We will apply systematic surface adsorption investigations, electronic structure analysis with energy decomposition analysis methods, and surface reactivity investigations with static (NEB) and dynamic (molecular dynamics) methods. A kinetic Monte Carlo approach will be developed. The goal is to pinpoint the most critical factors governing the stability of inhibitor layers across different systems and provide new avenues for experimental investigations in the future. To this end, we continue collaborating with the Bent group (Stanford U) to test the theoretical predictions.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partner: Professorin Dr. Stacey F. Bent