Showing papers on "Ellipsometry published in 1974"
IBM1
TL;DR: In this paper, a computer assisted, ellipsometric system performs in situ measurements on substrates and thin films in various atmospheres, at temperatures up to 1450 K. The light flux exiting from a rotating analyzer is measured at 512 equally spaced intervals, to yield a flux ellipse that is used for further analysis.
Abstract: A computer-assisted, ellipsometric system performs in situ measurements on substrates and thin films in various atmospheres, at temperatures up to 1450 K. A laser is used as the light source. The light flux exiting from a rotating analyzer is measured at 512 equally spaced intervals, to yield a flux ellipse that is used for further analysis. Data acquisition and data reduction are under control of an IBM System/7 computer. Ab initio calibration of the optical components using a fixed angle of incidence is possible; the cell windows are considered as small-retardation wave plates. Effects of non-ideality of polarizer and analyzer were negligible. Refractive indices of silicon (nSi*) and thermally grown silicon dioxide (nSiO2) are reported as functions of temperature up to 1350 K.
85 citations
TL;DR: In this article, the formation of the anodic oxide film on Pt has been investigated at wavelengths in the visible using voltage scanning ellipsometry, and the effective complex refractive index and thickness of the surface film have been calculated, using a three-layer model.
64 citations
TL;DR: In this paper, an improved criterion for computing the normalized 2 × 2 complex reflection matrix of an anisotropic surface from multiple-null ellipsometer measurements (in excess of three) is given.
Abstract: The technique of generalized ellipsometry is briefly reviewed. An improved criterion for computing the normalized 2 × 2 complex reflection matrix of an anisotropic surface from multiple-null ellipsometer measurements (in excess of three) is given. Generalized ellipsometry, together with the recently developed 4 × 4-matrix methods for the study of the reflection and transmission of polarized light by stratified anisotropic media, provide the basic tools to carry out and to interpret ellipsometric measurements on anisotropic structures. As an example, the case of uniaxial (absorbing) crystals, with the optic axis parallel to the surface, is considered. From three or more null measurements at a single unknown orientation of the optic axis, the five parameters (the ordinary and extraordinary complex indices of refraction and the angle of inclination of the optic axis from the plane of incidence) that characterize a uniaxial crystal of calcite are all determined.
52 citations
41 citations
TL;DR: A combination of ellipsometric data on the electronic transitions from occupied to unoccupied surface states and published photo emission data pertaining to the energy distributions of occupied surface states has been used to construct models of the surface state densities at clean semiconductor surfaces.
Abstract: A combination of ellipsometric data on the electronic transitions from occupied to unoccupied surface states and published photo emission data pertaining to the energy distributions of occupied surface states has been used to construct models of the surface state densities at clean semiconductor surfaces.
29 citations
TL;DR: In this paper, the thickness of an anodic oxide film and the potential of a prereduced electrode were determined for various current densities, and it was shown that the thickness affects the catalytic activity in an exponential way, where and δ are constants.
Abstract: Ellipsometry and standard electrochemical techniques are used to determine whether, and if so, how the thickness of an anodic oxide film affects the catalysis of the oxygen evolution reaction at platinum. A prereduced electrode is first polarized in sulfuric acid solution with a constant current density, for a given time and then the thickness, , of the anodic film and the electrode potential, , are determined for various current densities . It is found that the thickness of the oxide film affects the catalytic activity in an exponential way, i.e. where and δ are constants. For the same time of polarization both the oxide thickness and the electrode potential increase with the logarithm of the polarization current density, . The potential dependence is . This is in contrast with the value of about 115 mV usually reported for the oxygen evolution reaction. The latter value can be obtained only when the electrode is anodically treated at a current density, , and the relationship is subsequently determined at current densities . Ellipsometry shows that under these conditions the anodic film thickness remains essentially constant at the value achieved during the initial polarization at a higher current density.
29 citations
TL;DR: In this paper, a substantial phosphorus pileup was observed in the oxide in a thin layer near the ellipsometrically determined Si-SiO2 interface, and this layer was found to contain ∼2×1021 phosphorus atoms/cm3.
Abstract: Phosphorus redistribution during thermal oxidation of degenerately doped silicon was investigated using Auger electron spectroscopy and ellipsometry. Concentration profiles were determined with a combination of chemical and sputter etching techniques. A substantial phosphorus pileup was observed in the oxide in a thin layer near the ellipsometrically determined Si–SiO2 interface. Calibrated against standards of known concentration, this layer was found to contain ∼2×1021 phosphorus atoms/cm3, independent of the oxidation temperature between 850 and 1000 °C.
29 citations
TL;DR: In this article, the authors used ellipsometry to study the room temperature adsorption of H2, O2, Cl2, Br2, HCl, HBr, HI, H2S, CH3SH, NH3, PH3 and AsH3 on GaP(110) surfaces; CO, CO2 and CH4 did not adsorb.
28 citations
TL;DR: In this paper, the reflection properties of a uniaxial thin film on an isotropic substrate have been calculated in terms of a reflection matrix suitable for use in the Jones calculus.
Abstract: The reflection properties of a uniaxial thin film on an isotropic substrate have been calculated. The optic axis of the film is assumed to be parallel to the film surface. The reflection properties are summarized in terms of a reflection matrix suitable for use in the Jones calculus. A method is given for relating the reflection properties of this film-covered surface to the null settings of the polarizer and analyzer of a conventional ellipsometer. Results of calculations for a few specific cases are discussed.
21 citations
TL;DR: In this article, the principal angle of incidence (POMI) was measured using the return path of the Littrow-type spectrometer, requiring only one polarizer and no compensator.
18 citations
TL;DR: In this article, the Fenstermaker-McCrackin model for surface roughening modified to simulate the crack system was used to interpret the ellipsometric results of aluminum samples during fatigue cycling.
TL;DR: In this article, a combination of ellipsometry and reflectometry was used for the analysis of thin soap films of sodium dodecyl sulphate and benzenesulphonate.
Abstract: Thin soap films of sodium dodecyl sulphate and sodium dodecyl benzenesulphonate have been studied with a combination of ellipsometry and reflectometry. It is demonstrated that an optical three-layer model is superior to a one-layer model for the interpretation of the ellipsometric data. The refractive indices of the film core and the surface layers are determined, and it is found that the index for the surface is higher than that for the film core. The composition of the Newton type of film is discussed on the basis of these data.
TL;DR: The results of ellipsometric measurements on vitreous silica specimens subjected to various surface treatments such as mechanical polishing, chemical etching and sputter-cleaning are presented and discussed in this paper.
TL;DR: The problem of determining the optical constants of uniaxial anisotropic crystals by ellipsometry has been studied in this article, where it is shown that unless the optical axis is perpendicular to the surface, it is practically impossible to evaluate the component Nc = nc + ikc unless the values of n and k are very small.
Abstract: The problem of determining the optical constants of uniaxial anisotropic crystals by ellipsometry has been studied In case the optical axis is perpendicular to the surface—true in most of the cleavable crystals and in films where the anisotropy is induced by a size effect—it is practically impossible to evaluate the component Nc = nc + ikc (electric vector parallel with the optical axis) unless the values of n and k are very small Reasonable values of Na = na + ika can be obtained, regardless of the Nc value assumed
TL;DR: In this paper, ellipsometric measurements of light-absorbing monomolecular layers are described and combined with data from surface pressure studies and absorption spectra leads to a better insight into the structure of the monolayers.
Abstract: Ellipsometric measurements of light-absorbing monomolecular layers are described in this paper. Combination of the ellipsometric results with data from surface pressure studies and absorption spectra leads to a better insight into the structure of the monolayers.
TL;DR: In this article, an opto-electronic system for the ellipsometric analysis of thin films is described, based on interferometric principles, which permits accurate (σΔ = 0.25° and σψ=0.05°) and fast (down to 5 ms).
Abstract: A novel opto-electronic system for the ellipsometric analysis of thin films is described. Based on interferometric principles, the instrument permits accurate (σΔ=0.25° and σψ=0.05°) and fast (down to 5 ms) measurements. Spectroscopic applications seem promising, because the use of chromatic optical components has been avoided. The availability of an absolute reference rules out the possibility of systematic errors due to imperfections of components and of the window of the measuring cell used in ultra-high vacuum experiments.
TL;DR: There has been a considerable expansion recently, in the application of optical techniques, such as internal reflection and specular reflection spectroscopy, ellipsometry, interferometry, holography and optical microscopy, to the study of adsorption phenomena in electrochemical reactions as mentioned in this paper.
Abstract: THERE has been a considerable expansion recently, in the application of optical techniques, such as internal reflection and specular reflection spectroscopy, ellipsometry, interferometry, holography and optical microscopy, to the study of adsorption phenomena in electrochemical reactions1–3.
TL;DR: In this article, a reproducible oxide layer with an index of refraction n (Mo oxide ) = 2.10 was found, with a real part between 2.34 and 2.04 and an imaginary part of approximately 0.008.
TL;DR: In this paper, the composition, refractive index and thickness of thermally grown SiO2 layers grown onto Si single crystals were investigated by attenuated total reflection spectroscopy (ATR) and ellipsometry.
Abstract: The composition, refractive index and thickness of thermally grown SiO2 layers grown onto Si single crystals were investigated by attenuated total reflection spectroscopy (ATR) and ellipsometry. Under laboratory storage conditions the value of the refractive index proved to be time dependent. A saturated water vapour treatment at 79°C showed that the change in refractive index was caused by a small quantity of water vapour absorbed by the layer. A difference in the SiO2 absorption band between 1050 cm−1 and 1200 cm−1 was observed if the measurements were made by transmission or ATR techniques. In the ATR spectrum an absorption band becomes visible which is seen in the transmission spectrum only as a slope.
TL;DR: In this paper, a substantial phosphorus pileup was observed in the oxide in a thin layer near the ellipsometrically determined Si-SiO2 interface, and this layer was found to contain 2×1021 phosphorus atoms/cm3.
Abstract: Phosphorus redistribution during thermal oxidation of degenerately doped silicon was investigated using Auger electron spectroscopy and ellipsometry. Concentration profiles were determined with a combination of chemical and sputter etching techniques. A substantial phosphorus pileup was observed in the oxide in a thin layer near the ellipsometrically determined Si–SiO2 interface. Calibrated against standards of known concentration, this layer was found to contain ~2×1021 phosphorus atoms/cm3, independent of the oxidation temperature between 850°C and 1000°C.