Improvement of the electrical and interfacial propertie of TiN/ZrO2 by a modulated atomic layer deposition process with controlled O-3 dosing

Abstract

In this work, we have studied the atomic layer deposition (ALD) of ZrO2 under various O-3 dosing conditions and wsystematically investigated the interfacial properties of ZrO2/TiN during ALD fabrication using the CpZr(N(CH3)(2))(3) and O-3 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 O-3 dosing to realize the high performance of a metal-insulator-metal (MIM) capacitor device. The initial ALD cycles proceeded with low O-3 dosing to suppress the oxidation of the TiN substrate, and the subsequent bulk film was grown with high O-3 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.