Photoemission spectroscopy study of the oxidation of HfC(100)

Edamoto, K.; Shirotori, Y.; Satō, Tomohiko; Ozawa, K.

doi:10.1016/j.apsusc.2004.10.078

Cited by 10 publications

(4 citation statements)

References 12 publications

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“…[23][24][25] The small peak obtained for both films at around 16 eV might be attributed to a Hf-C bond on the surface of the films. [26] Figure 8b demonstrates the O 1s core level spectra obtained from both films. Each spectrum was deconvoluted into three separate peaks corresponding to different chemical states.…”

Section: Hfo 2 Film Characterizationmentioning

confidence: 98%

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Atomic Layer Deposition of HfO₂ Thin Films Employing a Heteroleptic Hafnium Precursor

Milanov

Parala

et al. 2012

Chemical Vapor Deposition

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The application of a heteroleptic hafnium amide-guanidinate precursor for the deposition of HfO 2 thin films via a water-assisted atomic layer deposition (ALD) process is demonstrated for the first time. HfO 2 films are grown in the temperature range 100-300 8C using the compound [Hf(NMe 2 ) 2 (NMe 2 -Guan) 2 ] (1). This compound shows self-limiting ALD-type growth characteristics with growth rates of the order of 1.0-1.2 Å per cycle in the temperature range 100-225 8C. The saturation behavior and a linear dependence on film thickness as a function of number of cycles are verified at various temperatures within the ALD window. The as-deposited HfO 2 films are characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS), and electrical measurements. For a direct comparison of the precursor performance with that of the parent alkyl amide [Hf(NMe 2 ) 4 ] (2), ALD experiments are also performed employing compound 2 under similar process conditions, and in this case no typical ALD characteristics are observed.

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Section: Hfo 2 Film Characterizationmentioning

confidence: 98%

“…[23] The C 1s core level XPS spectra (Fig. 8c) were composed of three separate component peaks at binding energies of around 289, 284.8, and 282,5 eV which can be ascribed to CÀO, CÀC, [27] and HfÀC, [26] respectively. In the literature, it has been shown that HfO 2 can react with atmospheric CO 2 to form carbonates.…”

Section: Hfo 2 Film Characterizationmentioning

confidence: 99%

Atomic Layer Deposition of HfO₂ Thin Films Employing a Heteroleptic Hafnium Precursor

Milanov

Parala

et al. 2012

Chemical Vapor Deposition

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“…However, the most interesting results on the interaction mechanism are reported in [9,10]. For example, the oxidation of HfC plane (100) was examined in [9] with photoemission spectroscopy using synchrotron radiation.…”

mentioning

confidence: 99%

“…For example, the oxidation of HfC plane (100) was examined in [9] with photoemission spectroscopy using synchrotron radiation. It was established that holding plane (100) in pure oxygen at room temperature causes it to interact with carbon atoms and form CO molecules.…”

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confidence: 99%

Protective oxide layers formed during electrochemical oxidation of hafnium carbide

Lavrenko

Talash

Desmaison-Brut

et al. 2009

Powder Metall Met Ceram

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The composition of oxide nanofilm formed on the HfC anode under electrolysis of a 3% NaCl solution at potentials between -0.20 and +1.90 V is studied using the potentiodynamic method of polarization curves and Auger electron spectroscopy and SEM methods. The film consists of the upper layer formed in polymolecular chemosorption of O 2 and Cl 2 gases followed by the HfO 2 + C (1 : 1) layer. Two inner layers represent a 7 at.% O 2 solid solution in HfC and a mixture of HfC 0.7 O 0.3 and HfO (7 : 1). The oxide film 30-40 nm thick formed at potentials up to 1.35 V is protective and ensures very high corrosion resistance of HfC without any further polarization.Although hafnium carbide is rather expensive, it is widely used in modern engineering to produce space rocket nozzles, structural components of gas-cycle nuclear jet engines, high-performance thermoionic generators, parts of power ion engines, and protective shields and control rods for nuclear reactors. Hafnium carbide is sometimes oxidized, oxide films being formed on its surface.We should examine the nature of the electrochemical oxidation of hafnium carbide at small potentials of anodic polarization to model the initial stages of forming such films not only in contact with marine water splashes but also with atmospheric oxygen.The HfC electrochemical oxidation is still to be examined, while HfC high-temperature oxidation is the subject of many papers. In particular, it was hypothesized in [1] that hafnium carbide and oxycarbide oxidized to HfO 2 through an intermediate phase of HfO 2 C (this hypothesis was not verified further). Two-stage HfC oxidation in air to 1200°C was established in [2]. It was shown that oxycarbide HfC x O y formed in the first stage and oxide HfO 2 in the second.Bargeron and his coauthors [3,4] conducted more detailed research into the oxidation of HfC between 1400 and 2060°C [3, 4] to reveal three oxide layers in the cross-section of oxidized samples. The lower layer represents carbide HfC with oxygen being dissolved in its lattice, the upper, quite porous layer contains HfO 2 , and the dense intermediate layer consists of hafnium oxide and carbon. It was shown that it was the intermediate layer that served as a barrier to the diffusion of oxygen inside the sample.

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Adsorption of atomic oxygen on HfC and TaC (110) surface from first principles

Liu¹,

Deng²,

Jin³

et al. 2012

Applied Surface Science

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Photoemission spectroscopy study of the oxidation of HfC(100)

Cited by 10 publications

References 12 publications

Atomic Layer Deposition of HfO₂ Thin Films Employing a Heteroleptic Hafnium Precursor

Atomic Layer Deposition of HfO₂ Thin Films Employing a Heteroleptic Hafnium Precursor

Protective oxide layers formed during electrochemical oxidation of hafnium carbide

Adsorption of atomic oxygen on HfC and TaC (110) surface from first principles

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Photoemission spectroscopy study of the oxidation of HfC(100)

Cited by 10 publications

References 12 publications

Atomic Layer Deposition of HfO2 Thin Films Employing a Heteroleptic Hafnium Precursor

Atomic Layer Deposition of HfO2 Thin Films Employing a Heteroleptic Hafnium Precursor

Protective oxide layers formed during electrochemical oxidation of hafnium carbide

Adsorption of atomic oxygen on HfC and TaC (110) surface from first principles

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Atomic Layer Deposition of HfO₂ Thin Films Employing a Heteroleptic Hafnium Precursor

Atomic Layer Deposition of HfO₂ Thin Films Employing a Heteroleptic Hafnium Precursor