Effect of interface layer on growth behavior of atomic-layer-deposited Ir thin film as novel Cu diffusion barrier

Choi, Byoung Geol; Lee, Jong Ho; Lee, Hong Kee; Kim, Joo Hyung

doi:10.1016/j.apsusc.2011.06.093

Cited by 15 publications

(6 citation statements)

References 25 publications

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“…A direct relationship between the surface energy and nucleation delay in Ir ALD using the Ir(acac) 3 /O 2 process was also demonstrated recently. 57 In addition, other effective variables, such as the adsorption coefficient of the precursor 67 and the hydrogen-donating ability of the substrate, 68 which is related to the nature of the precursor−substrate bonds, have been reported. However, these findings still seem to be applicable only to specific cases.…”

Section: Resultsmentioning

confidence: 99%

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

Park

Kim

et al. 2022

Chem. Mater.

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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 (C 18 H 27 IrO 3 or TICP) is used as an ALD precursor with molecular O 2 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 (<2 at. %) and low resistivity (13 μΩ cm) indicate that pure metallic Ir films are formed. The differential delay of nucleation depending on the substrate surface is explained in terms of the dominant surface functional group, indicating possible application of the current ALD process toward area-selective deposition of Ir. Density functional theory calculations show that the adsorption of the Ir precursor is feasible on Si and Ru but is unfavorable on hydroxyl-terminated SiO 2 . Ru is adopted as the seed layer for conformal deposition on a SiO 2 trench, and a step coverage of ∼100% is obtained. Finally, an Ir thin film grown on a threedimensional titanium substrate shows overpotentials (at 10 mA cm −2 ) of ∼65 mV for the hydrogen evolution reaction and ∼336 mV for the oxygen evolution reaction in an acid electrolyte, which suggest its potential application as a water-splitting catalyst.

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Section: Resultsmentioning

confidence: 99%

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

Park

Kim

et al. 2022

Chem. Mater.

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“…Conventional thermal Ir ALD has been carried out using a sequential combustion-type surface reactions using molecular oxygen as the oxidant at temperatures above 220°C. [64,156], and (ethylcyclopentadienyl)(1,5-cyclooctadiene)iridium (EtCpIr(COD)) [157][158][159]. Ir(acac) 3 has a lower vapor pressure than the latter two precursors, which necessitates heating to at least 150°C to get a reasonable vapor pressure for the ALD process [65].…”

Section: Ir Aldmentioning

confidence: 99%

Atomic layer deposition—Sequential self-limiting surface reactions for advanced catalyst “bottom-up” synthesis

Elam

Stair

2016

Surface Science Reports

271

215

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Catalyst synthesis with precise control over the structure of catalytic active sites at the atomic level is of essential importance for the scientific understanding of reaction mechanisms and for rational design of advanced catalysts with high performance. Such precise control is achievable using atomic layer deposition (ALD). ALD is similar to chemical vapor deposition (CVD), except that the deposition is split into a sequence of two self-limiting surface reactions between gaseous precursor molecules and a substrate. The unique self-limiting feature of ALD allows conformal deposition of catalytic materials on a high surface area catalyst support at the atomic level. The deposited catalytic materials can be precisely constructed on the support by varying the number and type of ALD cycles. As an alternative to the wet-chemistry based conventional methods, ALD provides a cycle-by-cycle "bottom-up" approach for nanostructuring supported catalysts with near atomic precision. In this review, we summarize recent attempts to synthesize supported catalysts with ALD. Nucleation and growth of metals by ALD on oxides and carbon materials for precise synthesis of supported monometallic catalyst are reviewed. The capability of achieving precise control over the particle size of monometallic nanoparticles by ALD is emphasized. The resulting metal catalysts with high dispersions and uniformity often show comparable or remarkably higher activity than those prepared by conventional methods. For supported bimetallic catalyst synthesis, we summarize the strategies for controlling the deposition of the secondary metal selectively on the primary metal nanoparticle but not on the support to exclude monometallic formation. As a review of the surface chemistry and growth behavior of metal ALD on metal surfaces, we demonstrate the ways to precisely tune size, composition and structure of bimetallic metal nanoparticles. The cycle-by-cycle "bottom up" construction of bimetallic (or multiple components) nanoparticles with near atomic precision on supports by ALD is illustrated. Applying metal oxide ALD over metal nanoparticles can be used to precisely synthesize nanostructured metal catalysts. In this part, the surface chemistry of Al 2 O 3 ALD on metals is specifically reviewed. Next, we discuss the methods of tailoring the catalytic performance of metal catalysts including activity, selectivity and stability, through selective blocking of the low-coordination sites of metal nanoparticles, the confinement effect, and the formation of new metal-oxide interfaces. Synthesis of supported metal oxide catalysts with high dispersions and "bottom up" nanostructured photocatalytic architectures are also included. Therein, the surface chemistry and morphology of oxide ALD on oxides and carbon materials as well as their catalytic performance are summarized.

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“…Several other factors such as the growth temperature, ,, substrate, ,− precursor selection, , and ALD process parameters have also been found to affect the nucleation delay. Various surface pretreatments, such as UV–ozone, oxygen plasma, argon plasma, and acid treatments, can improve or alter the nucleation of the ALD noble metals. − For example, surface carbon contamination can limit the adsorption of the noble metal precursor .…”

Section: Nucleationmentioning

confidence: 99%

Atomic Layer Deposition of Noble Metals and Their Oxides

2013

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Atomic layer deposition (ALD) is an attractive method to deposit thin films for advanced technological applications such as microelectronics and nanotechnology. One material group in ALD that has matured in 10 years and proven to be of wide technological importance is noble metals. In this paper, thermal ALD of noble metals and their oxides is reviewed. Noble metal films are mostly grown using O2 as the nonmetal precursor in a combustion-type chemistry. Alternatively, lower growth temperatures can be reached via noble metal oxide growth with consecutive reactions with ozone and H2. The use of true reducing chemistry (i.e., H2) is typical only for ALD of palladium at low temperatures. On the other hand, ALD of noble metal oxides has been limited with reactants such as ozone and O2 gas. In this review, reaction mechanisms in various types of processes are discussed and issues in nucleation are addressed. Deposition temperatures, film growth rates, and purities as well as evaporation temperatures used for noble metal precursors are tabulated for comparison.

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Effect of interface layer on growth behavior of atomic-layer-deposited Ir thin film as novel Cu diffusion barrier

Cited by 15 publications

References 25 publications

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

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

Atomic layer deposition—Sequential self-limiting surface reactions for advanced catalyst “bottom-up” synthesis

Atomic Layer Deposition of Noble Metals and Their Oxides

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