Scalable Inhibitor-Free Area-Selective Atomic Layer Deposition of High-Quality Nitride Films via Plasma-Driven Nucleation Engineering

Abstract Driven by the aggressive scaling of semiconductor devices and the rise of heterogeneous integration, area-selective atomic layer deposition (AS-ALD) has emerged as a key technique for reducing costs and improving integration precision through its self-aligned capability. However, conventional inhibitor-based selective deposition methods suffer from limitations in materials compatibility, thermal stability, and process integration. Meanwhile, current inhibitor-free approaches typically rely on additional etching steps, which introduce surface damage and increase fabrication costs. To address these challenges, we report an approach that integrates atomic layer nucleation engineering (ALNE) with surface reduction (SR) using a radio frequency substrate-biased plasma. This method enables highly selective, inhibitor-free AlN film deposition by removing adsorbed precursors and suppressing nitride formation on the nongrowth surface (tungsten, W), thereby preserving nucleation selectivity. To further enhance film quality, a remote hydrogen plasma pretreatment is introduced to mitigate plasma-induced degradation on the growth area (silicon dioxide, SiO2) during the ALNE and SR processes. The resulting AlN films exhibit exceptional compositional purity with negligible impurity incorporation, effectively resolving the intrinsic trade-off between nucleation delay and film integrity in AS-ALD. Consequently, a near-perfect selectivity is achieved for over 200 ALD cycles between SiO2 and W surfaces, yielding a selective thickness window exceeding 20 nm. Furthermore, this technique demonstrates robust pattern selectivity and strong scalability down to ∼20 nm line widths, providing a reliable, high-density, and cost-effective solution for integration in next-generation semiconductor technology nodes.