We report values of pseudodielectric functions $〈\ensuremath{\epsilon}〉=〈{\ensuremath{\epsilon}}_{1}〉+i〈{\ensuremath{\epsilon}}_{2}〉$ measured by spectroscopic ellipsometry and refractive indices $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{n}=n+ik$, reflectivities $R$, absorption coefficients $\ensuremath{\alpha}$ calculated from these data. Rather than correct ellipsometric results for the presence overlayers, we have removed layers as far possible using real-time capability ellipsometer...

This paper compares theory and experiment for behavior very near critical points. The primary experimental results are the "critical indices" which describe singularities in various thermodynamic derivatives correlation functions. These indices tabulated compared with theory. basic theoretical ideas introduced via molecular field approach, brings concept of an order parameter suggests that there close relations among different phase transition problems. Although this is qualitatively correct...

Using measured dielectric function data from 2.1 to 5.5 eV for chemical-vapor-deposition---grown smooth amorphous ($a$-Si) and microscopically rough fine-grained polycrystalline ($p$-Si) films, we show that the properties of layers thicknesses 100-500 \AA{}A are accurately modeled in effective-medium approximation. These essentially no macroscopic light scattering, thus inaccessible measurement by usual scattering techniques. The unambiguous identification microscopic roughness, as opposed...

We report pseudodielectric function 〈ε〉 data for AlxGa1−xAs alloys of target compositions x=0.00–0.80 in steps 0.10 grown by liquid-phase epitaxy and measured spectroellipsometry. Cleaning procedures that produce abrupt interfaces between the technologically relevant x≤0.5 ambient are described. The 〈ε2〉 corrected near fundamental direct absorption edge a Kramers–Kronig analysis 〈ε1〉 to circumvent limitation rotating-analyzer ellipsometric technique. results associated pseudooptical...

Standard textbook derivations of the Clausius–Mossotti (Lorentz–Lorenz) relation tend to obscure physical origin local-field effects by proceeding from macroscopic dielectric function equivalent homogeneous system microscopic parameters model. The and aspects can be made clearer reversing order, that is, first obtaining solution then implementing definition quantities as averages their counterparts. This approach also leads naturally into a treatment effective-medium theory description...

We describe the design, construction, alignment, and calibration of a photometric ellipsometer rotating-analyzer type. Data are obtained by digital sampling transmitted flux with an analog-to-digital converter, followed Fourier transforming accumulated data dedicated minicomputer. With operating mechanical rotation frequency 74 Hz, acquisition cycle requires less than 7 msec. The intrinsic precision attainable is high because limited only shot noise or source instabilities, even when...

We describe a Schottky-barrier electroreflectance (ER) technique for making high-resolution optical spectroscopic measurements on semiconducting materials. When combined with recent line-shape theories of low-field ER spectra, the method provides order-of-magnitude improvement in resolution structure and accuracy determination critical-point energies broadening parameters as compared to previous work higher interband transitions. The is applied GaAs, where separate contributions...

We perform an accuracy analysis of several possible reflectance–difference (RD) configurations that are compatible with standard molecular-beam epitaxy (MBE) growth chambers, and describe in detail optical-bridge system can determine relative changes RD signals as small 5×10−5 under conditions. Using this system, we the response GaAs for surface conditions at different wavelengths correlate these to simultaneously measured reflection high-energy electron diffraction (RHEED) intensities....

Synchrotron-radiation Schottky-barrier electroreflectance spectra from the $\mathrm{Ga} 3{d}^{V}$ core levels to lower $s{p}^{3}$ conduction band have shown that ${L}_{6}^{C}$ conduction-band minima are located 170 \ifmmode\pm\else\textpm\fi{} 30 meV in energy below ${X}_{6}^{C}$ GaAs. Here, we investigate implications of this ordering, which is opposite commonly accepted as correct. We find that, without exception, results previous experiments apparently supported ordering can be...

We have studied Raman scattering from 〈100〉 GaAs samples implanted with 270-keV As+ ions various fluences up to 3.2×1014 cm−2. In addition phonon density of states effects, we observe a softening and asymmetric broadening the allowed LO while small symmetry forbidden TO remains almost unchanged. The behavior modes can be explained quantitatively on basis ‘‘spatial correlation’’ model related q-vector relaxation induced by damage. Our interpretation is quite general makes it possible use...

We report the first systematic study of above---band-gap optical anisotropies in cubic semiconductors. The are large, order 1%. dominant intrinsic contributions for (110) Si and Ge due to surface many-body screening bulk spatial dispersion. Extrinsic from chemisorbed physisorbed species also play important roles.

The weak-field effective-mass-approximation calculations of the absorption coefficient in presence an electric field for direct and indirect transitions at a normal (${M}_{0}$) threshold are extended to arbitrary orientation anisotropic solid. To do this, systematic method evaluating density-of-states integrals arising electroabsorption or Franz-Keldysh effect is presented. Certain obtained prior ${M}_{0}$ which have not been previously evaluated given closed form. This also used derive...

Extremely uniform, microscopically smooth, large-grained polycrystalline Si films saturation doped with phosphorous to a carrier concentration $n=3.3\ifmmode\times\else\texttimes\fi{}{10}^{20}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ were prepared by combination of low-pressure chemical-vapor-deposition and heat-treating processes obtain samples suitable for measuring the small effects large impurity concentrations on above-band-gap dielectric properties Si. From 1.5 2.5 eV, heavy doping are...

Reported optical data for Au are investigated to determine the origin of their differences. A single-parameter model representing voids in an otherwise homogeneous medium is shown account major discrepancies above-band-gap ($E>2.5$ eV) ${\ensuremath{\epsilon}}_{2}$ spectra samples prepared different ways. Ellipsometric measurements on transmission-electron-microscopy (TEM) characterized thin-film energy range 1.5-5.8 eV support void but show importance measuring both...

Calculations of the imaginary part dielectric constant an anisotropic solid in region a critical point are used to obtain real through Kramers-Kronig relations. Changes and parts expressed closed form for all four types points. Description these changes can be made with only two functions. The effect finite extent band is investigated, it shown that previous calculations change constant, based on bands infinite extent, valid as long transitions restricted regions near point. Closed-form...

Reflectance-difference spectroscopy (RDS) is employed to study in situ the (4\ifmmode\times\else\texttimes\fi{}2), (1\ifmmode\times\else\texttimes\fi{}6), (4\ifmmode\times\else\texttimes\fi{}6), (3\ifmmode\times\else\texttimes\fi{}1), (2\ifmmode\times\else\texttimes\fi{}4)-\ensuremath{\alpha}, (2\ifmmode\times\else\texttimes\fi{}4)-\ensuremath{\beta}, (2\ifmmode\times\else\texttimes\fi{}4)-\ensuremath{\gamma}, c(4\ifmmode\times\else\texttimes\fi{}4), and...

The theoretical precision attainable from a number of types ideal null and photometric ellipsometers is investigated quantitatively. Photometric modulated ellipsometer systems are shown to be approximately comparable with respect when operating under shot-noise limited conditions. Differences due principally intrinsic detector noise levels, which more significant in designs. equations derive can used estimate practical measurement limits or choose components achieve specific objective.

Spectroscopic ellipsometric data from 1.5–5.8 eV has been analyzed to determine the in situ optical response of interface between Si and its thermally grown oxide. Results for <100>, <110>, <111> sample orientations show an width consisting atomically mixed O average stoichiometry . The are not consistent with either microroughness at or abrupt transition crystalline a significant accumulation amorphous interface, but rather support gradual region. thickness λ5461 refractive index this...

Chemical etching and cleaning procedures that produce the most abrupt dielectric discontinuities between bulk ambient (cleanest and/or smoothest surfaces) are determined by ellipsometry for single crystals of Si, Ge, some III-V compounds. Differences among high-symmetry orientations Si Ge indicate preferential may be a factor in minimizing amount interface material left at surface.

I describe some results of the first systematic study above-bandgap optical anisotropies in cubic semiconductors. The are large, order 1% relative reflectance differences for light polarized along orthogonal principal axes dielectric tensor anisotropic phase. Extrinsic contributions arising from surface films, physisorbed molecules, and chemisorption-induced changes electronic polarizability outermost plane substrate atoms identified. line shapes these reflectance-difference (RD) spectra...