Microstructure, porosity and roughness of RF sputtered oxide thin films: Characterization and modelization

Hassani, Fahd Oudrhiri; Presmanes, Lionel; Barnabé, Antoine; Tailhades, Philippe

doi:10.1016/j.apsusc.2008.03.149

Cited by 29 publications

(30 citation statements)

References 16 publications

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“…The calculation of these parameters is previously detailed in other publication [10]. The values obtained are in good agreement with the experimental results.…”

Section: Microstructural Modelsupporting

confidence: 77%

“…A sample stack structure glass/film/surface layer, was employed to extract the optical constants (n and k) of thin films. Most of the films studied are porous and the optical constants measured are related to the properties of both CoMnFeO 4 and voids [10]. Some samples however, are almost 100% dense, as demonstrated by surface area measurements and the high values of the refractive and absorptive indices (P0.5d50).…”

Section: Characterizations and Discussionmentioning

confidence: 94%

“…Surface roughness and porous layers were modelled with the Bruggeman effective medium approximation (BEMA) [12], where the layers are constituted of a mixture of dense CoMnFeO 4 and void. We observed that n and k values changed for materials characterized, this variation is due to the material's porosity [10]. The highest optical constants were then acquired for the samples deposited under the conditions leading to the highest film density, i.e.…”

Section: Characterizations and Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Microstructural characterization of CoMnFeO₄thin films deposited by radio-frequency sputtering

Hassani¹,

Presmanes

Barnabé

et al. 2013

MATEC Web of Conferences

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Abstract. CoMnFeO 4 thin films are stable materials useful to study the influence of radio-frequency sputtering experimental conditions, on the microstructure of oxide films. From various techniques of electronic microscopy, gas adsorption techniques and ellipsometry measurements, it was shown that such oxides films prepared with 0.5 Pa sputtering argon pressure and 5 cm target-substrate distance are very dense. On the other hand, the samples obtained under higher pressure and/or longer distance, are microporous. This porosity is mainly due to shadowing and energetic effects of sputtered particles. According to different characterization techniques, a simple model is proposed to describe the microstructure of the films studied.

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“…The calculation of these parameters is previously detailed in other publication [10]. The values obtained are in good agreement with the experimental results.…”

Section: Microstructural Modelsupporting

confidence: 77%

Section: Characterizations and Discussionmentioning

confidence: 94%

Section: Characterizations and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructural characterization of CoMnFeO₄thin films deposited by radio-frequency sputtering

Hassani¹,

Presmanes

Barnabé

et al. 2013

MATEC Web of Conferences

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“…This lower value of the magnetization in the case of thin film cobaltite cannot be explained by the presence of porosity. Indeed, it was shown that ferrite thin films deposited by RF sputtering from a ceramic target, at 0.5 Pa, are dense due to low shadowing effects during the film growth [42,43]. Most of the articles related to magnetic properties of oxide thin films obtained by sputtering further show that the samples obtained have much lower saturation magnetization than those measured on bulk materials [29,44,45].…”

Section: Magnetic Propertiesmentioning

confidence: 95%

“…F. Oudrhiri-Hassani [42] showed that the increase in porosity is only 15% when the pressure goes from 0.5 to 2 Pa, for ferrite thin films deposited by RF sputtering. This small increase in porosity cannot explain the dramatic decrease of the magnetization.…”

Section: Magnetic Propertiesmentioning

confidence: 99%

Preparation of iron cobaltite thin films by RF magnetron sputtering

et al. 2015

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International audienceIron cobaltite thin films with spinel structure have been elaborated by radio-frequency (RF) magnetronsputtering from a Co1.75Fe1.25O4 target. Influence of argon pressure on structure, microstructure and physicalproperties of films has been examined. Iron–cobalt oxide thin films essentially consist of one spinel phasewhen deposited at low pressure (0.5 and 1.0 Pa). At high pressure (2.0 Pa), the global stoichiometry of the filmis changed which results in the precipitation of a mixed monoxide of cobalt and iron beside the spinel phase.This in-situ reduction due to an oxygen loss occurring mainly at high deposition pressure has been revealed byX-ray diffraction and Raman spectroscopy. Microstructural evolution of thin film with argon pressure has beenshown by microscopic observations (AFM and SEM). The evolution of magnetic and electrical properties, versusargon pressure, has been also studied by SQUID and 4 point probe measurements

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Environmentally Tight TiO₂–SiO₂ Porous 1D‐Photonic Structures

García-Valenzuela

López‐Santos

Rico

et al. 2018

Adv Materials Inter

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materials with different refractive indexes (e.g., TiO 2 and SiO 2 ), has been proposed as a way of tailoring the optical behavior of broadband antireflection coatings used to maximize the performance of photovoltaic cells. [8] Porosity is also a key characteristic when preparing Bragg stacks acting as optical and optofluidic sensors for the detection of vapors or for liquid monitoring, respectively. [9] According to the principles of the effective medium approximation theory, [10] porosity can be utilized to adjust the overall refraction index of thin films as an average of the contributions of air (n air = 1.0) and film material (i.e., n b ). However, the adjustment of the optical properties of porous films faces the critical problem of their environmental instability due to the condensation of water (n w = 1.31) and other vapors into their open pores. Although this effect has been utilized for the optical detection of vapors using stacks of thin films in the form of Bragg structures, [9a,b,10] the affectation of optical properties in multilayers acting as 1D photonic structures can be a serious problem when dealing with passive optical systems. [12] This is clear in solar cells and other outdoor applications where optical instabilities due to water condensation have to be suppressed by polymer encapsulation during device assembly. In the present work, we propose the use porosity as an additional parameter to control the optical properties of multilayer stacks but, simultaneously, ensuring its environmental tightness and therefore, a stable outdoor functioning. To enhance film porosity we use the technique of magnetron sputtering at oblique angles (MS-OAD). [13] This geometrical configuration, either by e-beam evaporation or magnetron sputtering (MS), induces the growth of nanocolumnar films with porosities that may reach up to 50-60% of the film volume. [14] Highly porous OAD films and multilayers have been utilized in the pass for the fabrication of antireflection layers for passive optical applications, [7,11a,b] photo catalytic layers, [5,10a] humidity and other vapor sensors [10a,b,15] or optofluidic devices. [9c,d,16] Herein, we firstly prove that the optical behavior of MS-OAD multilayers in the form of Bragg reflectors (BR) or Bragg microcavities (BM) can be tailored by adjusting the porosity of the TiO 2 and SiO 2 thin films (e.g., making the TiO 2 compact and the SiO 2 highly porous, as proposed in previous works [7,12c] ). Then, using an optical monitoring procedure previously applied to study vapor Although thin film porosity is the basis of many optical sensors, it can be deleterious for a stable optical behavior of passive optical elements due to the condensation of water and other vapors in their pores. This paper proposes a new strategy for the magnetron sputtering (MS) fabrication of environmentally tight SiO 2 -TiO 2 porous multilayers. Thin films of these two oxides deposited in an oblique angle configuration (MS-OAD) present a nanocolumnar and highly porous nanostructure and, as ...

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Microstructure, porosity and roughness of RF sputtered oxide thin films: Characterization and modelization

Cited by 29 publications

References 16 publications

Microstructural characterization of CoMnFeO₄thin films deposited by radio-frequency sputtering

Microstructural characterization of CoMnFeO₄thin films deposited by radio-frequency sputtering

Preparation of iron cobaltite thin films by RF magnetron sputtering

Environmentally Tight TiO₂–SiO₂ Porous 1D‐Photonic Structures

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Microstructure, porosity and roughness of RF sputtered oxide thin films: Characterization and modelization

Cited by 29 publications

References 16 publications

Microstructural characterization of CoMnFeO4thin films deposited by radio-frequency sputtering

Microstructural characterization of CoMnFeO4thin films deposited by radio-frequency sputtering

Preparation of iron cobaltite thin films by RF magnetron sputtering

Environmentally Tight TiO2–SiO2 Porous 1D‐Photonic Structures

Contact Info

Product

Resources

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Microstructural characterization of CoMnFeO₄thin films deposited by radio-frequency sputtering

Microstructural characterization of CoMnFeO₄thin films deposited by radio-frequency sputtering

Environmentally Tight TiO₂–SiO₂ Porous 1D‐Photonic Structures