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Energy dispersive x-ray spectroscopy for nanostructured thin film density evaluation

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ABSTRACT

In this paper, we report on two fast and non-destructive methods for nanostructured film density evaluation based on a combination of energy dispersive x-ray spectroscopy for areal density measurement and scanning electron microscopy (SEM) for thickness evaluation. These techniques have been applied to films with density ranging from the density of a solid down to a few , with different compositions and morphologies. The high resolution of an electron microprobe has been exploited to characterize non-uniform films both at the macroscopic scale and at the microscopic scale.

No MeSH data available.


Standard deviation of areal density measurements for carbon films deposited in vacuum and in argon with 30 Pa and 300 Pa.
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Figure 8: Standard deviation of areal density measurements for carbon films deposited in vacuum and in argon with 30 Pa and 300 Pa.

Mentions: The application of EDS to the analysis of mesoscale inhomogeneity was investigated, exploiting carbon films [3]. In general, EDS scans performed on a wide film area result in a relatively low areal density standard deviation, since measured areal density values are averaged on a large surface. As the sampled region is reduced, standard deviation increases if the film presents inhomogeneities with a length scale comparable with the diameter of the sampled region. Thus, the inhomogeneity length scale can be estimated as the sampled area for which areal density standard deviation suddenly starts increasing. This approach was developed to introduce a quantitative criterion to compare films with qualitatively similar mesoscale structures. To this aim, we analysed carbon films produced by PLD with different inhomogeneity length scales: a compact coating produced in vacuum and two foams produced using argon as buffer gas with pressures around 30 Pa and 300 Pa. These films have different mesoscale morphologies (see figure 7) and, as a consequence, different densities (, and , respectively). Results are illustrated in figure 8. The sampled surface area ranges from 10 to . The areal density standard deviation for the compact coating is stable even for high magnifications. For carbon foam layers produced in argon at 30 and 300 Pa, a sudden increase is observed as the sampled area decreases below and , respectively. Thus, the inhomogeneity length scales can be estimated as and . These values confirm the morphological difference evident from SEM images and provide a quantitative criterion to compare the inhomogeneity length scale of films with similar morphology.


Energy dispersive x-ray spectroscopy for nanostructured thin film density evaluation
Standard deviation of areal density measurements for carbon films deposited in vacuum and in argon with 30 Pa and 300 Pa.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036461&req=5

Figure 8: Standard deviation of areal density measurements for carbon films deposited in vacuum and in argon with 30 Pa and 300 Pa.
Mentions: The application of EDS to the analysis of mesoscale inhomogeneity was investigated, exploiting carbon films [3]. In general, EDS scans performed on a wide film area result in a relatively low areal density standard deviation, since measured areal density values are averaged on a large surface. As the sampled region is reduced, standard deviation increases if the film presents inhomogeneities with a length scale comparable with the diameter of the sampled region. Thus, the inhomogeneity length scale can be estimated as the sampled area for which areal density standard deviation suddenly starts increasing. This approach was developed to introduce a quantitative criterion to compare films with qualitatively similar mesoscale structures. To this aim, we analysed carbon films produced by PLD with different inhomogeneity length scales: a compact coating produced in vacuum and two foams produced using argon as buffer gas with pressures around 30 Pa and 300 Pa. These films have different mesoscale morphologies (see figure 7) and, as a consequence, different densities (, and , respectively). Results are illustrated in figure 8. The sampled surface area ranges from 10 to . The areal density standard deviation for the compact coating is stable even for high magnifications. For carbon foam layers produced in argon at 30 and 300 Pa, a sudden increase is observed as the sampled area decreases below and , respectively. Thus, the inhomogeneity length scales can be estimated as and . These values confirm the morphological difference evident from SEM images and provide a quantitative criterion to compare the inhomogeneity length scale of films with similar morphology.

View Article: PubMed Central - PubMed

ABSTRACT

In this paper, we report on two fast and non-destructive methods for nanostructured film density evaluation based on a combination of energy dispersive x-ray spectroscopy for areal density measurement and scanning electron microscopy (SEM) for thickness evaluation. These techniques have been applied to films with density ranging from the density of a solid down to a few , with different compositions and morphologies. The high resolution of an electron microprobe has been exploited to characterize non-uniform films both at the macroscopic scale and at the microscopic scale.

No MeSH data available.