Half-Cycle-Selective Thermal Activation Decouples Oxide Quality from Interfacial Oxidation in Atomic Layer Deposition

Abstract As semiconductor devices approach nanometer-scale dimensions, functional oxide integration increasingly requires the simultaneous improvement of oxide quality and preservation of chemically fragile interfaces. Conventional atomic layer deposition (ALD) imposes a single substrate temperature on all half-reactions, creating an intrinsic trade-off in which thermal conditions that densify and crystallize oxides also accelerate oxidant-driven interfacial oxidation. Temporal thermal-budget engineering is introduced as a route to break this coupling by selectively positioning intense pulsed light (IPL)-induced transient thermal activation within the ALD cycle. Placing IPL before the metal precursor pulse activates precursor-related surface reactions, while allowing the substrate to cool before the subsequent O3 pulse. This half-cycle-resolved thermal control reduces impurities, increases film density, and promotes tetragonal ZrO2 crystallization at 220 °C, while avoiding pronounced interfacial oxidation on oxidation-sensitive electrodes such as TiN, Mo, and W. The resulting ZrO2 films exhibit a dielectric constant of ∼33 with a small interfacial equivalent oxide thickness. This concept is extended to HfO2 ALD on Mo, and its applicability to high-aspect-ratio trenches is verified by crystalline ZrO2 formation with comparable crystallinity along sidewall and bottom regions. These results establish temporal thermal-budget engineering as a broadly applicable strategy for oxide integration on oxidation-sensitive electrodes and complex three-dimensional architectures.