Atomic Layer Deposition of Ruthenium Using the Novel Precursor bis(2,6,6-trimethyl-cyclohexadienyl)ruthenium

Gregorczyk, Keith; Henn-Lecordier, Laurent; Gatineau, Julien; Dussarrat, Christian; Rubloff, Gary W.

doi:10.1021/cm2004825

Cited by 52 publications

(39 citation statements)

References 47 publications

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“…On the other hand, the nucleation of Ru on Al 2 O 3 exhibited rather poor chemisorption behavior compared to that on the other substrates. Growth retardation of Ru ALD on Al 2 O 3 was previously observed by Gregorczyk et al 22 They reported that Ru ALD using bis(2,6,6-trimethyl-cyclohexadienyl)Ru and O 2 showed a much longer incubation time on Al 2 O 3 than on SiO 2 (on SiO 2 ∼0 cycle, on Al 2 O 3 ∼250 cycles). These results reflect the further facile chemisorption property of the novel (1,5 hexadiene)(1-isopropyl-4-methylbenzene)Ru(0) precursor on diverse foreign surfaces, and, consequently, highly improved initial growth could be demonstrated in this work.…”

Section: ■ Results and Discussionsupporting

confidence: 61%

Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O₂

et al. 2014

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Ruthenium (Ru) and ruthenium oxide (RuO 2 ) thin films were grown by atomic layer deposition (ALD) using a novel zerovalent (1,5-hexadiene)(1-isopropyl-4-methylbenzene)Ru complex and O 2 as the Ru precursor and oxidant, respectively. The self-limiting growth mode for the Ru and RuO 2 ALD processes was achieved while varying the Ru precursor and O 2 feeding time. Metallic Ru films were deposited at growth temperatures of 230−350°C, while the temperature window for the growth of the RuO 2 film was limited to <230°C. At 270°C, the growth per cycle (GPC) of Ru ALD was 0.076 nm/cycle, and the incubation times of Ru on SiO 2 and TiN substrates were considerably short (3 cycles on SiO 2 , negligible on TiN) compared to that of Ru ALD from a high-valent Ru precursor and O 2 . The resistivity of the Ru film was as low as 29−36 μΩ·cm at growth temperatures of 270−350°C. On the other hand, the RuO 2 film was grown at a low temperature of 200°C and showed a GPC of 0.15 nm/cycle with a resistivity of ∼270 μΩ·cm. In situ quadruple mass spectrometry analysis of the CO 2 byproduct revealed that the amount of subsurface oxygen extracted during the Ru pulse half-cycle affected the resultant film phase, either Ru or RuO 2 , which was strongly influenced by the growth temperature. ■ INTRODUCTIONThe growth of nanoscale ruthenium (Ru) and ruthenium oxide (RuO 2 ) thin films has been spotlighted due to their promising characteristics such as low resistivity (Ru ∼7 μΩ·cm, RuO 2 ∼30 μΩ·cm), excellent chemical and thermal stabilities, high work functions (Ru ∼4.7 eV, RuO 2 ∼5.1 eV), and catalytic functionality. 1−15 These properties have enabled Ru-based thin films to be employed for energy device applications as a catalyst, in microelectronics as an electrode for dynamic random access memory (DRAM) capacitors, and as a seed layer for Cu electroplating. 2−7 Although a variety of deposition techniques for fabricating Ru and RuO 2 thin films have been used such as sputtering, pulse laser deposition, and chemical vapor deposition, atomic layer deposition (ALD) is the most appropriate method to grow uniform and conformal film over a 3-dimensional substrate with very precise composition/thickness controllability in nanotechnology applications. For Ru ALD, meanwhile, the choice of the Ru precursor is very important because not only the growth characteristics but also the film properties are highly affected by the Ru precursor used. For example, Ru(thd) 3 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate), Ru-(Cp) 2 (Cp = cyclopentadienyl), Ru(EtCp) 2 (EtCp = ethylcyclopentadienyl), and 2,4-(dimethylpentadienyl)-(ethylcyclopentadienyl)Ru are the most widely utilized Ru precursors in conjunction with O 2 as an oxidant. 8−12 Ru ALD using these precursors, however, showed extremely retarded nucleation and consequently resulted in long incubation cycles (e.g., >300 cycles on SiO 2 and 500 cycles on TiN when Ru(thd) 3 and O 2 were employed) at temperatures of 275−400°C . This poor nucleation behavior hinders the practical use of the Ru precursors listed ...

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Section: ■ Results and Discussionsupporting

confidence: 61%

Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O₂

et al. 2014

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“…7,15 Here we report rather low incubation times (0-40 cycles) on different substrates and a high growth rate of 0.1 nm/cycle for ALD with the RuO 4 -precursor. 7,15 Here we report rather low incubation times (0-40 cycles) on different substrates and a high growth rate of 0.1 nm/cycle for ALD with the RuO 4 -precursor.…”

Section: Introductionmentioning

confidence: 73%

Atomic layer deposition of ruthenium at 100 °C using the RuO₄-precursor and H₂

et al. 2015

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In this paper we report a low temperature (100 degrees C) ALD process for Ru using the RuO4-precursor (ToRuS (TM)) and H-2 as the reactant. The thermal decomposition behaviour of the precursor in the range of 50 degrees C-250 degrees C was investigated and it was found that thermal decomposition of RuO4 to RuO2 starts at a sample temperature of 125 degrees C. The RuO4/H-2 process (0.0045 mbar/4 mbar) was attempted at temperatures below this decomposition limit and it was found that ALD growth of pure Ru is possible in a narrow temperature window near 100 degrees C. The growth rate during steady state growth was found to be 0.1 nm per cycle. The Ru film nucleated easily on a wide range of substrates (H-terminated Si, TiN, Pt and Al2O3). Although the films are grown at a low temperature, they are considerably pure and are of good quality as evidenced by a resistivity of 18 mu Omega cm for an 18 nm film and a relative atomic concentration of impurities <5% as determined by XPS. It is hypothesized that the reaction of the RuO4 molecule with the Ru-surface leading to a monolayer of RuO2 is the mechanism that ensures a self-saturated behaviour of the first half reaction, which is a critical requirement to achieve a well-behaved ALD process

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“…The growth per cycle is 0.5 Å/cycle, which is higher than previously reported for ruthenium ALD. [22][23][24][25][26][27][28] There is an initiation delay of approximately 10 cycles before steady-state ALD of Ru is achieved. This delay is quite low compared to typical noble metal ALD, which often exhibits > 50-100 cycles of initiation delay.…”

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confidence: 99%

Isolating the Photovoltaic Junction: Atomic Layer Deposited TiO₂–RuO₂ Alloy Schottky Contacts for Silicon Photoanodes

Hendricks¹,

Scheuermann²,

Schmidt

et al. 2016

ACS Appl. Mater. Interfaces

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Access to the full text of the published version may require a subscription. Embargo information Access to this article is restricted until 12 months after publication by the request of the publisher. Just Accepted "Just Accepted" manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides "Just Accepted" as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. "Just Accepted" manuscripts appear in full in PDF format accompanied by an HTML abstract. "Just Accepted" manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). "Just Accepted" is an optional service offered to authors. Therefore, the "Just Accepted" Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the "Just Accepted" Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these "Just Accepted" manuscripts. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 transport is measured as film thickness increases from 3 to 45 nm for alloy compositions ≥ 16% Rights Embargo lift dateRu. Silicon photoanodes with a 2 nm surface SiO 2 layer that are coated by these alloy Schottky contacts having compositions in the range of 13-46% RuO 2 exhibit average photovoltages of 525 mV, with a maximum photovoltage of 570 mV achieved. Depositing TiO 2 -RuO 2 alloys on nSi sets a high effective work function for the Schottky junction with the semiconductor substrate, thus generating a large photovoltage that is isolated from the properties of an overlying oxygen evolution catalyst or protection layer.

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Atomic Layer Deposition of Ruthenium Using the Novel Precursor bis(2,6,6-trimethyl-cyclohexadienyl)ruthenium

Cited by 52 publications

References 47 publications

Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O₂

Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O₂

Atomic layer deposition of ruthenium at 100 °C using the RuO₄-precursor and H₂

Isolating the Photovoltaic Junction: Atomic Layer Deposited TiO₂–RuO₂ Alloy Schottky Contacts for Silicon Photoanodes

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Atomic Layer Deposition of Ruthenium Using the Novel Precursor bis(2,6,6-trimethyl-cyclohexadienyl)ruthenium

Cited by 52 publications

References 47 publications

Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O2

Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O2

Atomic layer deposition of ruthenium at 100 °C using the RuO4-precursor and H2

Isolating the Photovoltaic Junction: Atomic Layer Deposited TiO2–RuO2 Alloy Schottky Contacts for Silicon Photoanodes

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Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O₂

Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O₂

Atomic layer deposition of ruthenium at 100 °C using the RuO₄-precursor and H₂

Isolating the Photovoltaic Junction: Atomic Layer Deposited TiO₂–RuO₂ Alloy Schottky Contacts for Silicon Photoanodes