Atomic Layer Deposition of Iridium Using a Tricarbonyl Cyclopropenyl Precursor and Oxygen

Atomic layer deposition (ALD) is an advanced technology that can be used to deposit extremely thin and conformal films of iridium (Ir). However, ALD techniques for Ir coating are not well-developed. In particular, new Ir precursors with high reactivity at a suitable low temperature are essentially required. In this study, we report a novel ALD precursor with improved reactivity by introducing a cyclopropenyl ligand. Tricarbonyl (1,2,3-η)-1,2,3-tri­(tert-butyl)-cyclopropenyl iridium (C18H27IrO3 or TICP) is used as an ALD precursor with molecular O2 as a reactant. Ir films are grown by ALD on a Si substrate at deposition temperatures ranging from 200 to 325 °C, and an ALD window of 250–275 °C and self-limiting growth at a rate of 0.52 Å cycle–1 at 250 °C are observed. The negligible O impurity content (