Surface reaction kinetics of metal β-diketonate precursors with O radicals in radical-enhanced atomic layer deposition of metal oxides

Van, Trinh Tu; Chang, Jane P.

doi:10.1016/j.apsusc.2004.11.025

Cited by 32 publications

(12 citation statements)

References 39 publications

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“…31,32 In this work, Yb 2 O 3 growth using Yb(TMHD) 3 precursor was confirmed to behave similarly to the Y 2 O 3 and Er 2 O 3 analogs. Figure 1(a) shows the XPS spectrum for Yb 2 O 3 thin film deposited using Yb(TMHD) 3 and atomic oxygen.…”

Section: Resultssupporting

confidence: 58%

“…31,32 Thin films of Yb 3þ and Er 3þ codoped Y 2 O 3 were deposited on Si (100) substrates at 350 C using RE-ALD. A 3 array doser enabled the injection of 3 precursors without cross contamination.…”

Section: Methodsmentioning

confidence: 99%

“…The effects of energy transfer on the Er 31 1.54 lm luminescence in nanostructured Y 2 O 3 thin films with heterogeneously distributed Yb 31 and Er 31 codopants I. INTRODUCTION Scaling down rare earth doped systems can open paths to compact optical device design with applications from photovoltaics, sensors, light emitting diodes, and telecommunication systems.…”

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confidence: 99%

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The effects of energy transfer on the Er3+ 1.54 μm luminescence in nanostructured Y2O3 thin films with heterogeneously distributed Yb3+ and Er3+ codopants

Hoang

Schwartz

Wang

et al. 2012

Journal of Applied Physics

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Articles you may be interested inLuminescence thermometry below room temperature via up-conversion emission of Y2O3:Yb3+,Er3+ nanophosphors J.We report the effects of heterogeneous Yb 3þ and Er 3þ codoping in Y 2 O 3 thin films on the 1535 nm luminescence. Yb 3þ :Er 3þ :Y 2 O 3 thin films were deposited using sequential radical enhanced atomic layer deposition. The Yb 3þ energy transfer was investigated for indirect and direct excitation of the Yb 2 F 7/2 state using 488 nm and 976 nm sources, respectively, and the trends were described in terms of Forster and Dexter's resonant energy transfer theory and a macroscopic rate equation formalism. The addition of 11 at. % Yb resulted in an increase in the effective Er 3þ photoluminescence (PL) yield at 1535 nm by a factor of 14 and 42 under 488 nm and 976 nm excitations, respectively. As the Er 2 O 3 local thickness was increased to greater than 1.1 Å , PL quenching occurred due to strong local Er 3þ $ Er 3þ excitation migration leading to impurity quenching centers. In contrast, an increase in the local Yb 2 O 3 thickness generally resulted in an increase in the effective Er 3þ PL yield, except when the Er 2 O 3 and Yb 2 O 3 layers were separated by more than 2.3 Å or were adjacent, where weak Yb 3þ $ Er 3þ coupling or strong Yb 3þ $ Yb 3þ interlayer migration occurred, respectively. Finally, it is suggested that enhanced luminescence at steady state was observed under 488 nm excitation as a result of Er 3þ ! Yb 3þ energy back transfer coupled with strong Yb 3þ $ Yb 3þ energy migration.

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Section: Resultssupporting

confidence: 58%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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The effects of energy transfer on the Er3+ 1.54 μm luminescence in nanostructured Y2O3 thin films with heterogeneously distributed Yb3+ and Er3+ codopants

Hoang

Schwartz

Wang

et al. 2012

Journal of Applied Physics

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“…In this step, some thd groups are substituted by hydroxyl groups so that the molecular mass on the substrate surface decrease, which induces the QCM curve decrease, as shown in the inset of Figure 1a. Bi(thd) 3 (or Fe(thd) 3 ) molecules will not react with hydroxyls at low potential until H 2 O reacts with adjacent bismuth compounds deposited previously due to the effect of steric hindrance, 28 which will take several ALD cycles. A few cycles later, when most of the thd groups are substituted by hydroxyls, the physically absorbed Bi(thd) 3 molecules have the opportunity to react with the hydroxyls at low potential positions, as shown in Figure 2e,f.…”

Section: Resultsmentioning

confidence: 99%

Atomic Layer Deposition of BiFeO₃ Thin Films Using β-Diketonates and H₂O

et al. 2013

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Bismuth ferrite (BiFeO 3 ) thin films were grown by atomic layer deposition (ALD) by combining ALD of Bi 2 O 3 and Fe 2 O 3 and monitored by in-situ quartz crystal microbalance (QCM). The physical and chemical mechanisms of ALD of BiFeO 3 were studied according to the results of in-situ QCM and indicate that the deposition of Bi−O and Fe−O were self-limited by molecular sizes of precursors and chemical absorption between precursors and hydroxyl groups. Pure Bi 3+ and Fe 3+ with atomic ratio of 1:1 were formed during the ALD, and no evaporation of Bi atoms was found at 250 °C by X-ray photoelectron spectroscopy (XPS). Pure rhombohedral phase was formed in BiFeO 3 films after annealing at 650 °C by using X-ray diffraction (XRD). Polarization property of the ALD BFO film was observed and studied by using piezoresponse force microscopy (PFM). The ALD growth of BFO films demonstrates that ALD is an advanced deposition technique for BFO film preparation and memory device application.

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“…A detailed overview of the experimental apparatus used in this work for the deposition of metal oxide thin films using β-diketonate precursors and atomic oxygen has been described previously, so only a brief description is presented here. − The multibeam system used in this study consists of a 10 in.-outer diameter stainless steel main chamber with a load-lock assembly for clean sample insertion and removal without exposing the entire system to atmosphere. Affixed to the main chamber ports are several components: a coaxial microwave cavity radical beam source used to introduce highly reactive atomic oxygen to the sample, a six-precursor doser array used to introduce evaporated organometallic precursor fluxes to the sample, a temperature-controlled sample stage, and a hot-filament ion gauge to monitor the chamber pressure.…”

Section: Experimental Methodsmentioning

confidence: 99%

Magnetic Properties of CoFe₂O₄ Thin Films Synthesized by Radical-Enhanced Atomic Layer Deposition

Pham

Chang

Zurbuchen

et al. 2017

ACS Appl. Mater. Interfaces

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A radical-enhanced atomic layer deposition (RE-ALD) process was developed for growing ferrimagnetic CoFeO thin films. By utilizing bis(2,2,6,6-tetramethyl-3,5-heptanedionato) cobalt(II), tris(2,2,6,6-tetramethyl-3,5-heptanedionato) iron(III), and atomic oxygen as the metal and oxidation sources, respectively, amorphous and stoichiometric CoFeO films were deposited onto SrTiO (001) substrates at 200 °C. The RE-ALD growth rate obtained for CoFeO is ∼2.4 Å/supercycle, significantly higher than the values reported for thermally activated ALD processes. Microstructural characterization by X-ray diffraction and transmission electron microscopy indicate that the CoFeO films annealed between 450 and 750 °C were textured polycrystalline with an epitaxial interfacial layer, which allows strain-mediated tuning of the magnetic properties given its highly magnetostrictive nature. The magnetic behavior was studied as a function of film thickness and annealing temperature: saturation magnetization (M) ranged from 260 to 550 emu/cm and magnetic coercivity (H) ranged from 0.2 to 2.2 kOe. Enhanced magnetic anisotropy was achieved in the thinner samples, whereas the overall magnetic strength improved after annealing at higher temperatures. The RE-ALD CoFeO thin films exhibit magnetic properties that are comparable to both bulk crystal and films grown by other deposition methods, with thickness as low as ∼7 nm, demonstrating the potential of RE-ALD for the synthesis of high-quality magnetic oxides with large-scale processing compatibility.

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Surface reaction kinetics of metal β-diketonate precursors with O radicals in radical-enhanced atomic layer deposition of metal oxides

Cited by 32 publications

References 39 publications

The effects of energy transfer on the Er3+ 1.54 μm luminescence in nanostructured Y2O3 thin films with heterogeneously distributed Yb3+ and Er3+ codopants

The effects of energy transfer on the Er3+ 1.54 μm luminescence in nanostructured Y2O3 thin films with heterogeneously distributed Yb3+ and Er3+ codopants

Atomic Layer Deposition of BiFeO₃ Thin Films Using β-Diketonates and H₂O

Magnetic Properties of CoFe₂O₄ Thin Films Synthesized by Radical-Enhanced Atomic Layer Deposition

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Surface reaction kinetics of metal β-diketonate precursors with O radicals in radical-enhanced atomic layer deposition of metal oxides

Cited by 32 publications

References 39 publications

The effects of energy transfer on the Er3+ 1.54 μm luminescence in nanostructured Y2O3 thin films with heterogeneously distributed Yb3+ and Er3+ codopants

The effects of energy transfer on the Er3+ 1.54 μm luminescence in nanostructured Y2O3 thin films with heterogeneously distributed Yb3+ and Er3+ codopants

Atomic Layer Deposition of BiFeO3 Thin Films Using β-Diketonates and H2O

Magnetic Properties of CoFe2O4 Thin Films Synthesized by Radical-Enhanced Atomic Layer Deposition

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Atomic Layer Deposition of BiFeO₃ Thin Films Using β-Diketonates and H₂O

Magnetic Properties of CoFe₂O₄ Thin Films Synthesized by Radical-Enhanced Atomic Layer Deposition