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The mixing morphology control plays a crucial role in photovoltaic power generation, yet this specific effect on device performances remains elusive. Here, we employed computational approaches to delineate the photovoltaic properties of layered heterojunction polymer solar cells with tunable mixing morphologies. One-step quench and two-step quench strategies were proposed to adjust the mixing morphology by thermodynamic and kinetic effects. The computation for the one-step quench revealed that modulating interfacial widths and interfacial roughness could significantly promote the photovoltaic performance of layered heterojunction polymer solar cells. The two-step quench can provide a buffer at a lower temperature before the kinetic quenching, leading to the formation of small-length-scale islands connected to the interface and a further increase in photovoltaic performance. Our discoveries are supported by recent experimental evidence and are anticipated to guide the design of photovoltaic materials with optimal performance.

Present endeavor is devoted to investigate the flexural strength of beams fabricated by ordinary concrete (OC) and retrofitted with high strength concrete (HSC). Old part of beams is represented the deteriorated concrete; while the new part is referred to retrofitted portion of the deteriorated beam. Bond strength between two concrete parts of beam was enhanced via preparing rough interfacial surface in various ways, namely, sand blast, holes, grooves and steel brush. Experimental measurements are given in terms of flexural load – deflection relationship and cracking pattern of the beams. It is demonstrated that the beams with sand blast interfacial surface show reasonable performance with high flexural toughness and safer cracking at collapse.

In this paper, a new method to modify Ta underlayers by an argon ion etching technology is introduced. Surface roughness of Ta underlayers, as well as soft magnetic properties of post-deposited FeCoB films can be improved by applying a proper ion etching process. The reduction of magnetic coercivity of FeCoB films deposited on the modified Ta underlayers is attributed to the improvement of interfacial roughness, which can reduce magnetic ripples in magnetic films. The microwave damping linewidth of magnetic films is also found to be related to the interfacial roughness. Ta underlayers modified by the ion etching can reduce the influence of two-magnon scattering effect, and thus tune microwave properties of magnetic films. All the results prove that argon ion etching is an effective way to tailor magnetic properties of magnetic films.

Interfacial roughness is considered as a transition layer. A method of calculation of diffraction scans from multilayered structures with interfacial roughness, which is both fast and free of numerical errors, is developed., Diffraction in multilayers in the presence of interfacial roughness is studied theoretically, the roughness being considered as a transition layer. Exact (within the framework of the two-beam dynamical diffraction theory) differential equations for field amplitudes in a crystalline structure with varying properties along its surface normal are obtained. An iterative scheme for approximate solution of the equations is developed. The presented approach to interfacial roughness is incorporated into the recursion matrix formalism in a way that obviates possible numerical problems. Fitting of the experimental rocking curve is performed in order to test the possibility of reconstructing the roughness value from a diffraction scan. The developed algorithm works substantially faster than the traditional approach to dealing with a transition layer (dividing it into a finite number of thin lamellae). Calculations by the proposed approach are only two to three times longer than calculations for corresponding structures with ideally sharp interfaces.

The design procedures were discussed in detail for a normal incident chirped Mo/Si multilayer mirror with Group Delay Dispersion (GDD) of −3600 as 2 in the wavelength region of 13–17 nm. The GDD was calculated using an analytical approach by fitting the optical constants of the coating materials in the wavelength range of 12.8–17.2 nm, respectively. The final structure of the chirped mirror was obtained by using the simplex algorithm from the initial structure obtained by the genetic algorithm based on structure generated by a random generator. After considering the interfacial roughness and layers thickness deviation, the effects on the reflectivity and the GDD were discussed. It was found that the average reflectivity decreases from 5.98% to 4.22% and the average GDD decreases from −3561.86 as 2 to −3462.03 as 2 , the vibration of GDD were larger than that of the reflectivity. The reflectivity was affected greatly by the 9 th layer and the GDD was affected greatly by the 25 th layer when each layer thickness changes ±0.2 nm. Compared with the GDD, the reflectivity was affected greatly by the layer thickness error.

The use of cryogenic temperatures (∼77 K) during Au Schottky contact deposition onto n-GaAs produces an increase in barrier height from 0.73 eV for room temperature diodes to 0.82 eV. Not all Schottky metals show this enhancement—for example Pt and Ti do not show any significant change in barrier height whereas Au, Pd and Ni show increases between 7 and 18%. We used X-ray reflectivity to show that the main difference between Au deposited at 77 K and room temperature is a decreased metal roughness while the interfacial roughness between the Au and GaAs is basically the same. As the diodes are annealed to 300 °C both the difference in barrier height and interfacial roughness is lost. This is a simple method with potential for improving the performance of GaAs metal-semiconductor-field-effect-transistors (MESFETs).

Several features of the tendon-to-bone attachment were examined allometrically to determine load transfer mechanisms. The humeral head diameter increased geometrically with animal mass. Area of the attachment site exhibited a near isometric increase with muscle physiological cross section. In contrast, the interfacial roughness as well as the mineral gradient width demonstrated a hypoallometric relationship with physiologic cross-sectional area (PCSA). The isometric increase in attachment area indicates that as muscle forces increase, the attachment area increases accordingly, thus maintaining a constant interfacial stress. Due to the presence of constant stresses at the attachment, the micrometer-scale features may not need to vary with increasing load.

Multilayer coatings for reflecting hard X-rays up to 80 keV, like W/Si and Pt/C, have been studied for several years. To go to higher energies, in the range of 100 keV to 250 keV, one needs coatings with smaller d-spacings than can currently be made with these material combinations, and a lower interfacial roughness. With the new material combinations of WC/SiC the interface roughness can be reduced down to between 0.23 nm and 0.25 nm enabling bi-layer thicknesses down to 1.0 nm to reflect efficiently. The production of thinner period coatings thus enables the possibility for focusing optic designs with reasonable focal lengths and throughput up to 250 keV.

The effects of thermal annealing on CdTe/CdS heterojunctions have been investigated by means of the grazing incidence x-ray scattering technique. Changes in the interface morphology due to heat treatment are characterized quantitatively in terms of a set of parameters including the interfacial roughness and correlation lengths of the layer thickness fluctuations.

The particle packing of MP tape media is explored by means of a new measurement technique. Utilizing a narrow gap length record head, the tape is evaluated throughout its thickness with the use of an incremental DC erase measurement. A quantitative analysis of the medium noise spectra at different erase currents allows for the packing fluctuations at different depths into the tape to be proportioned. The technique provides a method for evaluating the interface between the magnetic recording layer and non-magnetic underlayer in dual-layer tape, and measurements indicate that interfacial roughness at the magnetic coating backside in some dual-layer media is a major source of medium noise.

The microtopography of silicon and silicon oxide surfaces in SIMOX structures is investigated by scanning tunneling microscopy. A method of using scanning tunneling microscopy to study Si/SiO2 interfacial roughness is developed for this purpose. It is shown that the relief of the silicon surface in SIMOX structures is smoother than that of the oxide surface. The observed Si/SiO2 interfacial roughness is due to oxygen ion implantation in the silicon single crystal. The roughness of the SiO2 and Si surfaces at the Si/SiO2 interface is compared for the standard and high-temperature oxidation of the silicon single crystal.

We present experimental neutron reflectivity results showing that it is possible to use V–Ni multilayered systems as cold neutron monochromators and supermirrors. Compared to the Ni–Ti optics devices, the V–Ni stacks present sharp interfaces characterised by a low interfacial roughness and very small interfacial diffusion.

A series of type-II GaAs/AlAs superlattices epitaxially grown with different interrupts have been investigated using the techniques of grazing incidence X-ray scattering and diffraction. The interrupts are specifically designed to alter the interfacial roughness in the superlattices for the present study. Various structural parameters including the layer thickness, interfacial roughness, and intra-layer correlation lengths of fluctuations in the quantum-well widths have been determined. These results are compared with measurements made on the same set of samples using photoluminescence and optical imaging techniques.

multilayers on Si(100) were prepared by ion-beam sputter deposition. By using a grazing incidence x-ray reflectivity technique, the layer thickness and interfacial roughness of the multilayers were quantitatively characterized. In particular, the differences in structural features between the on interface and the on interface, as well as the possible inhomogeneity of the layers, were successfully revealed. The x-ray reflectivity results are consistent with the high-resolution electron microscopy observations. The process of the growth of the multilayers is also discussed.

We report on further development of the optical, structural performances and temporal stability of Al(1%wtSi)/Zr multilayers. The multilayers with variable periods (from 10 to 80) are fitted by four-layer model. Below 40 periods, the surface and interfacial roughnesses are increased with the period numbers, but not decrease the reflectivity of Al(1%wtSi)/Zr multilayers. Above 40 periods, such as 80 periods, the reflectivity is down to 34.7% due to larger roughness and worse interfacial boundary. To improve the reflectivity, we modify some parameters during deposition process. The results in the EUV reflectivity show that the reflectivity of the sample with 40 periods is increased from 41.2% to 48.2%. The temporal stability of Al(1%wtSi)/Zr samples with different annealing temperatures has been observed over 35 days.

In this chapter, the basic design features of intrinsically tuneable FBARs are considered focusing on the Bragg reflectors for the solidly mounted resonators. Effects of the electrodes and other layers on the tuneable performance of the FBARs including tuneability, Q-factor, and electromechanical coupling coefficient are also addressed.

Recent reports on the current-voltage (I-V) characteristics of SrTiO3 and (Ba,Sr)TiO3 thin film capacitors with Pt electrode suggest that their leakage properties are controlled by Schottky emission from cathode. However, their dynamic permittivities obtained from the Schottky plot are always much smaller than those expected from optical measurements. The most plausible approach to explain this disagreement is to incorporate the effect of electric field enhancement due to interfacial roughness into the Schottky emission model. Electric field at the interface, for the first order approximation, can be given by [(r+t)/r](V/t), where r, t and V respectively denote radius of curvature representing interfacial roughness, dielectric thickness and applied voltage. This model predicts that I-V characteristics are the functions of r and V for the ultimate case of r ≪ t. We have closely studied the I-V characteristics of sputter-deposited SrTiO3 films and have obtained the results which strongly support ou...

The correlation of roughness profiles of different interfaces in a periodical multilayer affects the reciprocalspace distribution of the diffusely reflected X-ray intensity. This distribution has been calculated by means of the Distorted-Wave Born Approximation (DWBA) method and compared with the results of X-ray reflectometry on periodical metallic multilayers. It has been shown that the measurement of the reciprocal-space distribution of diffusely scattered intensity is a suitable non-destructive method to investigate the roughness replication in multilayers.

A theoretical analysis, based on the Fourier transformation approach, has been developed for the frictional pull-out of a single fibre with a rough interface from an elastic matrix. A Fourier series is used to express the amplitude function of the interfacial roughness, and solutions for the fibre pull-out stress are obtained for two different boundary conditions: one models a matrix containing an array of unidirectional fibres and the other a single fibre–matrix system. The interfacial roughness between the fibre and matrix is found to have a pronounced influence on the fibre sliding behaviour.

The problems inherent in the fabrication of short period multilayer mirrors are discussed and results of the synthesis of multilayer structures with nanometer period are presented. The shortest period observed is 13 A for WSi and WB 4 C sputtered multilayers. Measurements of near normal incidence reflectivity at λ = 31–32A are presented for WSc multilayers with a period approximately 16 A. The measured reflectivity reaches a maximum of 3.3% and is in good agreement with theoretical modeling after the inclusion of interfacial roughness.

In this paper, the x-ray diffraction profiles of multilayer with uncorrelated rough interfaces are directly simulated using kinematic theory of x-ray diffraction. The result shows that the decrease of the reflective intensity caused by the interfacial roughness is more severe than that caused by random fluctuation of period of the same degree, and the decrease of the reflective intensity of high order Bragg deffraction is more rapid than that of low order ones. So it is very important to reduce the interfacial roughness in the deposition and in the annealing of multilayer films.

Surface and interface roughness of 40-A oxynitride films grown on preoxidized (100) silicon surfaces in a nitric oxide (NO) ambient at 800°C have been investigated using atomic force microscopy with power spectral density, and cross-sectional transmission electron microscopy measurements. The results showed that the NO oxynitride surface is smoother and has less interfacial roughness compared to the thermal oxide (without NO anneal). These results are important given the current technological interest in oxynitrides for ultrathin gate dielectric applications.

The interfacial roughness in multilayer films is described by a model in which the parameters are directly related to those of microscopic growth processes. The height‐height correlation function is extracted from this model. Stationary and nonstationary roughness are discussed. The diffuse intensity in diffraction from multilayer films that have various degrees of correlation in roughness between interfaces is calculated. The presence of perfect or partial interfacial roughness correlation can be distinguished unambiguously in the diffusely scattered intensity.

This article examines the characterization of buried magnetic interfaces using a relatively new technique, the second-harmonic magneto-optic Kerr effect (SHMOKE), and a more established technique, x-ray reflectivity (XRR). Results are presented on the interdiffusion and interfacial roughness of Ta/NiFe and TaN/NiFe interfaces. The samples were characterized as deposited and after a 270 °C, 2 h anneal. SHMOKE analysis indicates that the Ta/NiFe interfaces are more susceptible to interdiffusion than the TaN/NiFe interfaces, during deposition as well as anneal. These results are consistent with XRR analysis of the samples and suggest that further development of SHMOKE may be of enormous benefit to interfacial magnetic metrology.

It is widely believed that the secondary flow mechanism, namely the generation of secondary flow in the gas phase due to circumferentially varying interfacial roughness, plays an important role in the liquid film distribution in horizontal annular flow. We study this mechanism numerically using the HARWELLFLOW 3D computer program. We use wall functions to account for wall roughness, and verify this approach to comparing our predictions with the data of Nikuradse and Hanjalic & Launder. We then apply the methodology to the prediction of secondary flow in a pipe subjected to differential wall roughness, and show that the contribution of the secondary flow in the gas is hitherto overestimated by up to an order of magnitude.

This paper reports the fabrication and evaluation of Mo/Al and Mo/Si multilayer films (MLs) for a wavelength of 18.5 nm. Calculated reflectivities of Mo/Al MLs at an incident angle of 10° were about 7% higher than those of Mo/Si MLs. MLs were fabricated using an RF-magnetron sputtering deposition system. The measured reflectivity of Mo/Al MLs was 33.5%. The cause of the decreasing reflectivity was supposed to be the surface and interfacial roughness. In the surface observation utilizing atomic force microscopy, the surface roughness of Mo/Al MLs was dominated by the Al layer. Therefore, the conditions for fabricating Al films were optimized.

Using a two-dimensional image plate detector we measured the non-specular X-ray reflectivity from (Ni 0.81 Fe 0.19 )/Au metallic multilayers. The image plate pattern consists of periodic diffuse sheets which arise from the coherence of the roughness between different interfaces, and are strongest at the position of the Bragg peaks. We analyze the expression for the diffuse scattering cross-section derived from the distorted-wave Born approximation and separate the coherent and incoherent contributions. This allows us to determine the interface roughness parameters, assuming it to be self-affine. From the line shape of the diffuse sheets we determine the partial replication of the roughness for different length scales.

We have prepared polycrystalline Co2FeSi thin films on a number of seed layers to optimize their structural and magnetic properties. Using a Cr/Ag combined seed layer, films have been produced with extremely low interfacial roughness (

In the conventional X-ray reflectivity (XRR) analysis for the estimation of multilayer surface, the reflectivity is calculated based on the Parratt formalism, accounting for the effect of roughness by the theory of Nevot-Croce. However, the calculated results have shown often strange behaviour due to the fact that the diffuse scattering at the rough interface was not taken into account in the equation. Then we developed new improved formalism to correct this mistake. In this study, we show applying of new improved formalism using a transmission electron microscope (TEM) observation result. The result of interfacial roughness by using the conventional XRR formulae showed large difference with the TEM result, and derived wrong structure of surface. While, the result by new improved formalism reproduce the TEM result well, but need appropriate parameters in transmission coefficient. It shows that new improved XRR formalism derives more accurate analysis of the XRR, but the reduced Fresnel coefficients with physical grounds in the reflectivity equation are need in further research.

We studied about new design of supermirror and inerfacial roughness for the X-ray telescope above 40 keV. We have developed hard X-ray telescope above 10 keV using platinum-carbon multilayer supermirror. In our balloon borne experiment, named InFOC(mu) S launched in this June, the supermirror expand the upper-limit of energy band of X-ray telescope up to 40 keV. We are trying to improve supermirror design to have energy band up to 70 keV. In previous design, the absorption of upper layers and lower-limit of layer thickness prevent us to extend the energy band. In this paper, we optimize design parameters of supermirror and use second Bragg peak, and we obtained high reflectivity up to 70 keV. We studied about interfacial roughness of platinum-carbon multilayer to design the supermirror, because the interfacial roughness is very serious problem such high energy region. In many cases, simple Debye-Waller factor can't represent measured reflectivity. We introduced two different roughness for Pt/C and C/Pt interfaces. This model well fit the data and make us possible to design the supermirrors.

Multilayers for the water window region of the soft x rays have been prepared by pulsed laser ablation with amorphous Ni50Nb50 and amorphous C. The structural characterization of the multilayers, period d = 2.41 nm, shows that the interfaces are sharp with a roughness of only 0.4 nm that is chemical, not morphological, in origin. The interface roughness was found to be uncorrelated in the direction normal to the plane of the film. The normal incidence soft-x-ray reflectivity of the multilayer at 4.85-nm wavelength is 0.06%, 1 order of magnitude lower than the theoretically predicted value. However, the resolution limit lambda/Delta lambda of the multilayer was found to be 16.7, close to the theoretically predicted value. (C) 1997 Optical Society of America.

We have studied interfacial roughness in amorphous W/Si multilayers grown by rf sputtering at different deposition parameters by cross-sectional transmission electron microscopy, x-ray reflectivity, and diffuse x-ray scattering. The diffuse scattering intensity has been recorded in an unprecedented wide range of parallel momentum transfer, 5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ A${\mathrm{\r{}}}^{\mathrm{\ensuremath{-}}1}$\ensuremath{\leqslant}${\mathit{q}}_{\mathrm{\ensuremath{\parallel}}}$\ensuremath{\leqslant}1 A${\mathrm{\r{}}}^{\mathrm{\ensuremath{-}}1}$, giving access to the height-height self- and cross-correlation functions on lateral length scales between a few \AA{} and 1 \ensuremath{\mu}m. The results are compared for the different samples and discussed in view of the deposition parameters. \textcopyright{} 1996 The American Physical Society.

X-ray reflection from periodical multilayers with randomly rough interfaces has been described within the distorted-wave Born approximation. The method is suitable for calculating both specular x-ray reflection and nonspecular (diffuse) scattering. In this paper, both in-plane and vertical correlations of the roughness profiles have been considered and it has been demonstrated that the vertical roughness correlation substantially affects the nonspecular scattering. The theory can explain resonant effects observed in the beam scattered nonspecularly from a periodical multilayer. The theoretical approach has been used for the study of interfacial roughness in a long-periodic AlAs/GaAs multilayer and good agreement has been achieved between the experimental results and the theory.

Interfacial roughness correlation in W/C multilayer films with periods of 23 angstroms, 30 angstroms, and 37 angstroms is examined with x-ray diffraction using (lambda) in the 10 angstroms to 13 angstroms range and (lambda) equals 1.54 angstroms. Transverse scans through multilayer Bragg reflections are analyzed to determine the magnitude and lateral correlation length of the component of interfacial roughness that is perfectly correlated through the multilayer stack. The results are independent of wavelength, even though hard x rays sample match more deeply into the film, indicating that interfacial roughness is not changing through these films.

Nondestructive and element-specific x-ray techniques have been employed to probe the interfacial microstructures in various multilayer semiconductor systems. Structural information on interfacial roughness, thickness of buried epilayer, correlations of intralayer and interlayer microstructures, atomic density profile and local structures about selected atomic species in the materials were obtained.

Transmission electron microscopy images and hard x-ray reflectivity curves are used to obtain information on the growth characteristics of x-ray multilayer mirrors. A multi-resolution approach based on wavelet analysis is used to decompose the interface profiles obtained from transmission electron microscopy images into a number of different spatial frequency ranges. The replication factor (vertical) and the characteristic length (lateral) of the interfacial roughness are determined in these spatial frequency ranges. By changing the upper or lower limits of the wavelet transform of the x-ray reflectivity curves, the structure uniformity (lateral) and evolution of the surface damage (vertical) are determined. These results are significant for the study of the growth characteristics of ultrathin x-ray multilayer mirrors and enable more effective methods to determine their imperfections.

Estimations of surface and interfacial roughness by x-ray reflectivity measurements were compared with those from TEM and AFM observations. The x-ray reflectivity was calculated based on the Parratt formalism, accounting for the effect of roughness by the theory of Nevot-Croce. Estimated surface and interface roughnesses from the x-ray reflectivity measurements did not correspond to the TEM image observation results. This disagreement suggests that the modified Fresnel reflectance coefficient introduced by Nevot and Croce cannot be applied for a surface and interface having a large degree of roughness. In addition, the calculated result showed a strange phenomenon in that the amplitude of the oscillation due to interference effects increases in the case of a specific roughness of the surface. This strange result suggests that there is a serious problem in how the effect of the roughness is added to the Parratt formalism. The modification of Nevot and Croce for Fresnel coefficients has been used for only surface and interface reflection. However, the modification of the transmission coefficients has an important role when the roughness of the surface or interface is large, and the effect of diffuse scattering due to the roughness should not be ignored in the calculation. This is an essential problem regardless of the size of the roughness. An inaccurately addition of the Fresnel reflectance coefficient to the Parratt formalism causes this disagreement and strange result, and therefore the effect of roughness was properly incorporated into the theoretical formulation of the x-ray reflectivity. In this paper, we only describe these problems. Further investigation of this problem will be reported elsewhere where we propose a new formalism to derive the x-ray reflectivity for systems having surface and interfacial roughness.

The structures of ultrathin sputtered Cr/C multilayers were determined by high-resolution transmission electron microscopy. The evolution of layer thickness errors, interdiffusion and interfacial roughness were simulated using time series models. The results show that with increasing of interdiffusion and roughness the multilayer thickness ratio changes, thereby influencing the optical performance. All structural parameters show good correlation with and influence adjacent layers. The system errors of the deposition equipment can also be evaluated by the models.

Co(0002) oriented thin films were grown by MBE techniques on Al2O3(1120) oriented substrates with a typical miscut of 0.5° – 1°. The samples were characterized by high resolution x-ray reflectivity measurements and Laue oscillations of the (0002) Bragg peak, yielding a density profile for the film including a surface oxide layer and interfacial roughness parameters.

Using modern high-speed computers, one can now model specular reflectivity experiments with unprecedented precision. For thin film and multilayer systems exhibiting large characteristic interfacial roughness or interdiffusion and for polymeric materials with unusual density profiles, a discrete layer-modeling scheme is required for an accurate and physically meaningful interpretation of the modeled profile. The incorporation of such a layer-generating algorithm into a non-linear least squares fitting routine can greatly increase the quality of the information available in reflectivity measurements. Applying these techniques to the modeling of grazing-angle diffraction data is particularly important for neutrons since the characteristic penetration depths are, in general, some four times larger than for x rays. We will outline the grazing-angle analogue of reflectivity profile analysis using the distorted-wave approximation and discuss possible applications.

AlN/InN heterostructures have been fabricated on yttria stabilized zirconia (YSZ) substrates using the low temperature pulsed laser deposition (PLD) growth technique, and their structural and electronic properties have been investigated with various characterization techniques. We have found that using the low temperature PLD growth technique allows us to prepare abrupt and high quality AlN/InN heterointerfaces with an interfacial roughness less than 2 nm. Photoemission spectroscopy measurements using hard X-ray around 6 keV have revealed that the conduction band offset at the AlN/InN heterointerface is as large as 3.3 eV.

The glancing angle x-ray diffraction spectra of GexSi1−x/Si superlattices grown by MBE under different temperatures are investigated. Three different types of the intensity distributions of diffraction peaks are observed, which are believed to be corresponded with different situations of interfaces. If all the interfaces in superlattice structure are highly flat, up to 17 orders diffraction peaks are identified with their intensities modulated by a periodical envelope function, otherwise the distribution of diffraction intensities follows simply a decaying function. A quantitative analysis using computer simulation based on the modified Bragg's law and the optical multilayer theory is used to derive the structural parameters including the thicknesses of Si and GexSi1−x layers, superlattice period, Ge content x and the degree of interfacial roughness.

On examine l'applicabilite de la spectroscopie du rendement electronique total TEY sous incidence rasante induit par rayons X comme outil pour sonder les microstructures dans les materiaux de synthese en couches. On montre qu'un modele propose pour decrire la variation angulaire du rendement electronique total sous incidence rasante est en bon accord avec les resultats experimentaux. Les mises en evidence theorique et experimentale montrent que la profondeur de sondage dans cette spectroscopie de TEY angulaire pour les structures en couches est comparable a la longueur d'attenuation caracteristique des rayons X et n'est pas limitee par le libre parcours moyen inelastique des electrons secondaires qui dominent le signal TEY. Cette technique peut par consequence etre utilisee comme un outil pour les etudes microstructurales en profondeur de divers materiaux en couches

Qualitative and quantitative characterisation of Co/Cu multilayers prepared by magnetron sputtering have been performed using X-ray diffraction. To gain information on the quality of the layering within the samples, both specular and off-specular (diffuse) measurements have been made, with the experimental scans interpreted using numerical techniques. We find interfacial roughness that is partially correlated through the multilayer stack.

We report a new material combination, C/Si, for normal-incidence multilayer mirrors in the wavelength region 25-30 nm. The multilayers, fabricated by ion-beam-sputtering deposition, were characterized by near-normal-incidence reflectance measurements by using a discharge source and a grazing-incidence monochromator. The highest measured near-normal-incidence reflectance was R = 23% (25.6 nm), R = 20% (28.3 nm), R = 25% (30.4 nm) at incident angles of 10 degrees , 12 degrees , and 4 degrees , respectively. The multilayers were also characterized by transmission electron microscopy, which revealed sharp layer interfaces and low interfacial roughness.

Structural and optical changes in a GaAs surface due to rf sputter deposition of SiO2 were investigated by means of transmission electron microscopy (TEM) and spectroscopic ellipsometry (SE). A blight-field image indicates the occurrence of a surface-modified layer of about 7-9 nm thickness in the GaAs surface after SiO2 deposition, at an rf power density of 1.7 W/cm2. A lattice image shows the increased interfacial roughness between GaAs and SiO2 upon the deposition. The thickness of the optically-modified layer in SiO2-deposited GaAs is estimated by SE, using the amorphous semiconductor dispersion model. At the lower rf power deposition, the extents of damage estimated by TEM and SE were found to be enhanced. Both rf-power and SiO2-deposition-rate dependences of damage suggest that impingement by non-depositing particles in the initial stage causes surface modification.