Atomic Layer Nucleation Engineering: Inhibitor-Free Area-Selective Atomic Layer Deposition of Oxide and Nitride

Abstract

Area-selective atomic layer deposition (AS-ALD) has attracted attention due to the process demand for semiconductor device scaling. Here, we propose the “atomic layer nucleation engineering (ALNE)” technique, an inhibitor-free AS-ALD of an oxide (Al2O3) and a nitride (AlN) with nearly 100% selectivity between the dielectric (SiO2) and the metal (Pt). The key is to add a radio-frequency substrate bias after precursor exposure and purge in each ALD cycle, where the energy from the ignited plasma selectively removes the precursors on the metal owing to the relatively lower binding energy compared to those on the dielectric, thereby inhibiting the film growth on the metal. This critical step enables the AS-ALD without selectivity loss up to 100 ALD cycles, leading to significant thickness differences of ∼14.9 and ∼8.7 nm for Al2O3 and AlN between the dielectric and metal surfaces. The realization of AS-ALD of Al2O3 and AlN by ALNE is also confirmed on the Pt/SiO2 patterned substrate. The ALNE offers a novel concept and approach to achieve high-selectivity AS-ALD, which is critical to further extension of Moore’s law.