Preparation of iridium metal films by spray chemical vapor deposition

Abstract

<jats:title>Abstract</jats:title><jats:p>Metal Ir films were prepared by spray chemical vapor deposition (CVD) in air from an Ir precursor, (1,3-cyclohexadiene)(ethylcyclopentadienyl)iridium, Ir(EtCp)(CHD). Film deposition was ascertained at 270–430°C on a SiO<jats:sub>2</jats:sub>/Si substrate and the deposition rate increased with the deposition temperature but was saturated above 330°C. The obtained films consisted of Ir metal without any iridium oxide impurity irrespective of the deposition temperature. Films tended to orient to (111) with increasing deposition temperature. Resistivity of these Ir films decreased with increasing film thickness and reached to values on the order of 10<jats:sup>-6</jats:sup> Ω・cm, which was the same order of the values for bulk Ir metal. Good step coverage was observed for the Ir metal films deposited at 270°C and 330°C. This shows that the simple spray CVD process in air is a good candidate for depositing Ir metal films with good conductivity and step coverage.</jats:p>

High-Performance Iridium Thin Films for Water Splitting by CVD Using New Ir(I) Precursors

“…The precursor chemistry of Ir­(III) is thus not further discussed; however, the reader is referred to review articles by Karakovskaya et al, Garcia et al and Vasilyev et al, which thoroughly summarize the known Ir­(III) and Ir­(I) precursors. The general bonding motif for Ir­(I) precursors is a stabilizing neutral ligand such as 1,5-cyclooctadiene (COD), − 1,3-cyclohexadiene (CHD), carbonyl (CO), , and ethylene (C 2 H 4 ), while the anionic ligand, e.g., acetylacetonate (acac), cyclopentadiene (Cp), or ketoiminate, shields the positively charged iridium central metal atom. With the variation of the neutral and anionic ligand backbone, parameters such as volatility, thermal stability, and reactivity of the complexes can be precisely tuned to facilitate low-temperature MOCVD processes or to create liquid precursors for direct liquid injection (DLI) CVD processes with enhanced growth rates.…”