Improvement of the electrical and interfacial propertie of TiN/ZrO2 by a modulated atomic layer deposition process with controlled O3 dosing

Highlights: • Atomic layer deposition of ZrO₂ is performed with varied O₃ dosing. • The interfacial layer of high-k ZrO₂/TiN is studied. • Modulated ALD reduces interface layer and enhances electrical properties. • This study presents a useful strategy for metal/insulator interface optimization. -- Abstract: In this work, we have studied the atomic layer deposition (ALD) of ZrO₂ under various O₃ dosing conditions and systematically investigated the interfacial properties of ZrO₂/TiN during ALD fabrication using the CpZr(N(CH₃)₂)₃ and O₃ reactant combination. In a typical ZrO₂ ALD process, the oxidation condition fundamentally determines the interface oxidation and bulk film properties. High oxidation power is required to enhance the crystallinity of the ZrO₂ film with low defect densities but inevitably causes the growth of the interfacial oxide, which reduces the dielectric constant of the resulting film. In the current study, we propose a modulated ALD process with controlled O₃ dosing to realize the high performance of a metal-insulator-metal (MIM) capacitor device. The initial ALD cycles proceeded with low O₃ dosing to suppress the oxidation of the TiN substrate, and the subsequent bulk film was grown with high O₃ dosing to improve the crystallinity of the ZrO₂. As a result, we achieved a high dielectric constant ZrO₂ material with a reduced defect density and a minimum interface capacitance equivalent thickness (CET) of the TiN/ZrO₂/TiN MIM capacitor under modulated oxidation conditions. This work provides a useful method to control the interface and bulk properties of dielectric layers at the atomic level.