Nucleation and Conformality of Iridium and Iridium Oxide Thin Films Grown by Atomic Layer Deposition

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Miika Mattinen
  • Jani Hämäläinen
  • Feng Gao
  • Pasi Jalkanen
  • Kenichiro Mizohata
  • Jyrki Räisänen
  • Riikka Puurunen

  • Mikko Ritala
  • Markku Leskelä

Research units

  • University of Helsinki
  • VTT Technical Research Centre of Finland

Abstract

Nucleation and conformality are important issues, when depositing thin films for demanding applications. In this study, iridium and iridium dioxide (IrO2) films were deposited by atomic layer deposition (ALD), using five different processes. Different reactants, namely, O2, air, consecutive O2 and H2 (O2 + H2), and consecutive O3 and H2 (O3 + H2) pulses were used with iridium acetylacetonate [Ir(acac)3] to deposit Ir, while IrO2 was deposited using Ir(acac)3 and O3. Nucleation was studied using a combination of methods for film thickness and morphology evaluation. In conformality studies, microscopic lateral high-aspect-ratio (LHAR) test structures, specifically designed for accurate and versatile conformality testing of ALD films, were used. The order of nucleation, from the fastest to the slowest, was O2 + H2 > air ≈ O2 > O3 > O3 + H2, whereas the order of conformality, from the best to the worst, was O3 + H2 > O2 + H2 > O2 > O3. In the O3 process, a change in film composition from IrO2 to metallic Ir was seen inside the LHAR structures. Compared to the previous reports on ALD of platinum-group metals, most of the studied processes showed good to excellent results.

Details

Original languageEnglish
Pages (from-to)10559-10569
Number of pages11
JournalLangmuir
Volume32
Issue number41
Publication statusPublished - 18 Oct 2016
MoE publication typeA1 Journal article-refereed

ID: 10942752