Atomic Layer Deposition of Iridium Thin Films Using Sequential Oxygen and Hydrogen Pulses

Atomic layer deposition (ALD) is an advanced thin-film deposition method based on self-limiting surface reactions that allows for the controlled deposition of conformal, high-quality thin films of various materials. In this study, we aimed to explore how modifying the deposition chemistry affects the growth and properties of iridium films. We demonstrated a new ALD process using sequential pulses of iridium acetylacetonate [Ir(acac) 3 ], oxygen (O 2 ), and hydrogen (H 2 ) and compared this to the established Ir(acac) 3 + O 2 process in the wide temperature range of 200–350 °C. A reaction scheme is proposed to explain how both oxygen and hydrogen affect the film growth. Comprehensive information on film properties was obtained for both processes. In particular, the strong (111) texture seen in this study has not been reported before for ALD iridium films. Changes in film properties, especially lowered resistivity, stronger (111) texture, and faster nucleation compared to the Ir(acac) 3 + O 2 process, should motivate further studies on O 2 + H 2 processes of platinum metals.