Atomic Layer Deposition of Iridium Oxide Thin Films from Ir(acac)₃ and Ozone

Abstract

Iridium oxide thin films were grown with atomic layer deposition (ALD) from Ir(acac) 3 and ozone between 165 and 200 °C. The films were successfully deposited on soda lime glass, silicon substrate with native oxide, and Al 2 O 3 adhesion layer. Saturation of the growth rate with respect to both precursors was verified and the film thickness depended linearly on the number of deposition cycles applied. The iridium oxide films had low impurity contents and good adhesion to all tested surfaces. IrO 2 film deposited at 185 °C had homogeneous depth profile and contained 3.5 at % hydrogen and less than 0.5 at % carbon impurities. Resistivities of about 40 nm thick IrO 2 films varied between 170 and 200 µΩ cm. The films deposited above 200 °C were metallic iridium. All the films deposited were crystalline according to X-ray diffraction patterns.