Microdensitometer Analysis Of Electron Micrographs Research Articles

Electron micrography and x-ray study of dip-lacquered LiF (220)

It has been proposed to use the 220 reflection of LiF with a multilayer deposited upon the top for simultaneous spectroscopy near Fe-k and O-k and below the C-k absorption edge (284 eV) in x-ray astronomy. We demonstrate that a substantial reduction of surface roughness is obtained by dip lacquering state-of-the-art polished LiF(220) surfaces. Using a microdensitometer analysis of electron micrographs of surface replicas and x-ray reflection, we have measured approximately 10-A rms roughness of Au-coated dip-lacquered LiF(220) crystals, as opposed to approximately 60 A measured on the bare LiF(220) crystal surface.

Extreme UV and x-ray scattering measurements from a rough LiF crystal surface characterized by electron micrography

XUV and x-ray scattering by a LiF crystal is measured. The angular distribution of the scattered radiation (ADSR) reveals characteristic features, side peaks or asymmetry. The surface of the sample is statistically characterized by a microdensitometer analysis of electron micrographs resolving the short spatial wavelengths of the surface roughness. This analysis shows that the surface has a large microroughness with an autocovariance function which is Gaussian in its initial portion. The first-order perturbation vector theory of the roughness-induced scattering leads to an interpretation of the ADSR features in terms of the modulation of the surface power spectral density function associated with the microroughness by an optical factor. The possibility of obtaining short scale roughness characterization from XUV or x-ray measurements is discussed.

Defining the fractal nature of thin-film top surfaces from microdensitometer analysis of electron micrographs of surface replicas

Defining the fractal nature of thin-film top surfaces from microdensitometer analysis of electron micrographs of surface replicas

Defining the fractal nature of thin‐film top surfaces from microdensitometer analysis of electron micrographs of surface replicas

In this paper, the very first results are reported about searching for the fractal nature of thin‐film top surfaces from the surface relief reconstructed by microdensitometer analysis of an electron micrograph of a shadowed replica of the surface. It is found that such a reconstruction could be very helpful when dealing with the fractal nature of a surface.

Microdensitometer analysis of electron micrographs of shadowed surface replicas: A powerful method in surface structure characterization

Microdensitometer analysis of electron micrographs of shadowed surface replicas: A powerful method in surface structure characterization

Microdensitometer analysis of electron micrographs of shadowed surface replicas: A powerful method in surface structure characterization

From the micrograph density of a shadowed carbon replica of a surface it is possible by using a microdensitometer analysis to rebuild line by line the profile of that surface. The different stages necessary for such a reconstruction are summarized. Various reconstructions connected with metallic, optical, dielectric and biological surfaces are presented. Those restored profiles are used to estimate the moments (particularly the second one named the autocovariance function) that summarize statistical information on the various characteristic lengths describing the surface.

Influence of some parameters on the surface profile restored from microdensitometer analysis of electron micrographs of surface replicas

From the micrograph density of a shadowed carbon replica of a surface it is possible, by using a microdensitometer analysis, to rebuild line by line the profile of that surface. After summarizing the different stages necessary for such a reconstruction, we study the influence on the restored profiles of the various parameters that are encountered during the various steps of experiment and computation. It is shown that the most important parameters are the shadow-casting angle, microdensitometer scanning aperture, and filtering characteristics. Other parameters such as magnification micrograph, microdensitometer scanning speed, and microdensitometer noise play a minor role. The best way to choose and fit the appropriate value of the various parameters is discussed.

Improvement in the reconstruction of surface profile deduced from microdensitometer analysis of electron micrographs of shadowed surface replicas

The different steps leading to the determination of a surface profile deduced from microdensitometer analysis of electron micrographs of shadowed surface replicas are reviewed. It is shown that monodimensional median filtering is sometimes inadequate to remove the low-frequency noise generated by the Levy–Wiener process. A new treatment is proposed that corrects this disadvantage.

Spectral-density function of the surface roughness for polished optical surfaces

The spectral density functions g(k) of the surface roughness for polished optical surfaces of CaF2, MgF2, and LiF are computed from autocovariance functions, which in turn have been determined from surface profiles obtained by using a microdensitometer analysis of electron micrographs of shadowed surface replicas. The fast-Fourier-transform algorithm and a smoothing procedure have been used to determine the g(k) estimates. It is shown that g(k) is not a Gaussian function throughout, as is usually assumed. Spectral density functions gS′(k) of the surface slopes are also computed, and it is shown that results obtained are consistent with those deduced from g(k). Limitations of our method at low spatial frequency are discussed. An analytical model for g(k) is investigated that should be useful in performing theoretical calculations on scattering problems.

Study of surface roughness for thin films of CaF 2 deposited on glass substrates

The dependence of the surface roughness of CaF 2 thin films on the film thickness d is determined by a technique using microdensitometer analysis of electron micrographs of surface replicas. The rms surface roughness δ and the autocovariance length σ have been found to depend linearly on d in the range 250 < d < 4000 Å. Discrepancies between our values of δ and σ, and corresponding values deduced from interferometric and surface plasmon techniques are discussed.

Height and slope distributions for surfaces of rough metallic deposits

This paper deals with the accurate determination of height and slope distributions for surfaces of rough metallic deposits (magnesium, copper, silver, and gold). These distributions are computed using a microdensitometer analysis of electron micrographs of surface replicas. It is shown that most of the surfaces examined have reasonable Gaussian height and slope distributions. Apart from magnesium surfaces, the rms roughnesses determined from these distributions agree (within the accuracy range of their measurements) with rms roughnesses deduced from the autocovariance functions computed previously. Within the framework of scalar scattering theory, some emphasis is laid on the value of slopes to draw certain conclusions about the validity of the assumptions under which the scalar scattering theory is derived.

Validity of surface-roughness study using microdensitometer analysis of electron micrographs of surface replicas

We reconstruct the micrograph images from surface profiles previously obtained1 by using microdensitometer analysis of electron micrographs of surface replicas. These micrograph images compare favorably with the original images.