Reza Bavadi

Islamic Azad University, Teheran, Tehrān, Iran

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Publications (6)2.7 Total impact

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    ABSTRACT: In this paper the influence of temperature on the 3-D surface morphology of titanium nitride (TiN) thin films synthesized by DC reactive magnetron sputtering has been analyzed. The 3-D morphology variation of TiN thin films grown on p-type Si (100) wafers was investigated at four different deposition temperatures (473 K, 573 K, 673 K, 773 K) in order to evaluate the relation among the 3-D micro-textured surfaces. The 3-D surface morphology of TiN thin films was characterized by means of atomic force microscopy (AFM) and fractal analysis applied to the AFM data. The 3-D surface morphology revealed the fractal geometry of TiN thin films at nanometer scale. The global scale properties of 3-D surface geometry were quantitatively estimated using the fractal dimensions D, determined by the morphological envelopes method. The fractal dimension D increased with the substrate temperature variation from 2.36 (at 473 K) to 2.66 (at 673 K) and then decreased to 2.33 (at 773 K). The fractal analysis in correlation with the averaged power spectral density (surface) yielded better quantitative results of morphological changes in the TiN thin films caused by substrate temperature variations, which were more precise, detailed, coherent and reproducible. It can be inferred that fractal analysis can be easily applied for the investigation of morphology evolution of different film/substrate interface phases obtained using different thin-film technologies.
    MATERIALS SCIENCE-POLAND 03/2015; 33(1):137-143. DOI:10.1515/msp-2015-0010 · 0.37 Impact Factor
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    ABSTRACT: The study presents a multi-scale microstructural characterization of three-dimensional (3-D) micro-textured surface of titanium nitride (TiN) thin films prepared by reactive DC magnetron sputtering in correlation with substrate temperature variation. Topographical characterization of the surfaces, obtained by atomic force microscopy (AFM) analysis, was realized by an innovative multifractal method which may be applied for AFM data. The surface micromorphology demonstrates that the multifractal geometry of TiN thin films can be characterized at nanometer scale by the generalized dimensions Dq and the singularity spectrum f(α). Furthermore, to improve the 3-D surface characterization according with ISO 25178-2:2012, the most relevant 3-D surface roughness parameters were calculated. To quantify the 3-D nanostructure surface of TiN thin films a multifractal approach was developed and validated, which can be used for the characterization of topographical changes due to the substrate temperature variation.
    MATERIALS SCIENCE-POLAND 01/2015; DOI:10.1515/msp-2015-0086 · 0.37 Impact Factor
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    ABSTRACT: The morphological parameter of a thin film surface can be characterized by power spectral density (PSD) functions which provide a better description to the topography than the root mean square roughness and imparts several useful information of the surface including fractal and superstructure contributions. In the present work PSD spectra computed from atomic force microscopy (AFM) data were used for studying the morphology of three different titanium nitride thin films obtained by dc magnetron sputtering system. The power values of PSD for the AFM data were determined by the fast Fourier transforms algorithms. We investigate the effect of substrate temperature and crystallite sizes on the roughness of thin films surface.
    Journal of Fusion Energy 12/2012; 31(6). DOI:10.1007/s10894-012-9510-z · 0.99 Impact Factor
  • R. Bavadi · S. Valedbagi ·
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    ABSTRACT: The physical properties of the titanium nitride thin film have been prepared on p-type silicon (100) substrates by at room temperature by reactive DC magnetron sputtering technique using pure Si target with varying oxygen partial pressure during growth at reported. The oxygen partial pressure in the growth chamber is varied between (97 % argon) and (3 % oxygen). The X ray diffraction (XRD) analysis showed that all the films were polycrystalline.
    Materials Physics and Mechanics 01/2012; 15(2):167-172.
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    ABSTRACT: The TiN thin films were deposited on p-type silicon (100) substrates using reactive planar DC magnetron sputtering system. The target was 99.99% pure Ti. The reactive sputter gas was a mixture of Ar (99.999%) and N2 (99.999%) with the ratio Ar (97%) and N2 (3%) by volume. Structural characterization of the coating was done using X-ray diffraction (XRD). The surface roughness of the coating was determined using an Atomic Force Microscope (AFM). The reflectivity of thin films was investigated by a spectrophotometer system. The X-ray diffraction measurements showed that by increasing the substrate temperature during the growth, change in crystalline structure will occur. The crystallite size of the films determined by Scherrer’s equation, and the crystallite size measured by AFM also increased by increasing the substrate growth temperature. The surface reflectivity measurements indicate that by increasing the substrate growth temperature, the optical properties of the films changes. The change in optical properties and crystalline structure of the films indicate that substrate growth temperature plays an important role in structure and morphology of the grown layers. KeywordsDC magnetron sputtering–Titanium nitride compound–Substrate temperature
    Journal of Fusion Energy 03/2011; 30(4):333-337. DOI:10.1007/s10894-011-9383-6 · 0.99 Impact Factor