TY - JOUR
T1 - Nucleation and Conformality of Iridium and Iridium Oxide Thin Films Grown by Atomic Layer Deposition
AU - Mattinen, Miika
AU - Hämäläinen, Jani
AU - Gao, Feng
AU - Jalkanen, Pasi
AU - Mizohata, Kenichiro
AU - Räisänen, Jyrki
AU - Puurunen, Riikka L.
AU - Ritala, Mikko
AU - Leskelä, Markku
PY - 2016/10/18
Y1 - 2016/10/18
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84991772112&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.6b03007
DO - 10.1021/acs.langmuir.6b03007
M3 - Article
AN - SCOPUS:84991772112
SN - 0743-7463
VL - 32
SP - 10559
EP - 10569
JO - Langmuir
JF - Langmuir
IS - 41
ER -