Rutherford Backscattering Spectrometer Research Articles

An examination on the porosity of Er[formula omitted] doped Ca[formula omitted] crystal using the Rutherford back-scattering method

This work investigates the porosity of ErF3 doped CaF2 crystals using the Rutherford back-scattering (RBS) method. Two ErF3:CaF2 samples of 2.0 and 5.5% doping ratios were prepared using the Bridgman method. The RBS spectra of these samples at two incident angle configurations of the projectile alpha, i.e., 0 and 30 degree, were collected using the Rutherford back-scattering spectrometer at the Joint Institute for Nuclear Research in Dubna, Russia. The measured spectra were analyzed with sample models of porous materials using the SIMNRA program. It turns out that the porous volume ratio and diameter are probably in the intervals of 18 to 22% and 2.4×1018 to 3.0×1018 atoms per cm2, respectively. However, the RBS method exhibits significant uncertainty, impeding our ability to establish a correlation between porosity characteristics and doping ratios.

Evaluating the Ge: C ratio on the bonding structure, hardness, and residual stress of Ge1-x-Cx coatings fabricated by the PE-CVD method

In the present research, the effect of the Ge: C ratio was evaluated and explained on the bonding structure, the hardness, and residual stress of germanium-carbon (Ge1-x-Cx) coatings fabricated by plasma-enhanced chemical vapor deposition (PECVD) method. For characterizing the coatings, a field emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectrometer (EDS), transmission electron microscope (TEM), Raman spectrometer, Rutherford backscattering spectrometer (RBS), elastic recoil detection (ERD) analysis, X-ray photoelectron spectrometer (XPS), nanoindentation test, and cohesion test were used. by increasing the flow rate ratio of CH4:GeH4 and as a result of decreasing the ratio of Ge: C, the fraction of sp2 C-C and sp3 Ge-C bonds were increased and the fraction of Ge-Ge bonds was decreased. The hardness of the Ge1-x-Cx coatings was heavily reliant on changes in the Ge: C ratio and, consequently, the fraction of the bonds incorporated within the coating structure. To achieve a hard coating, the selection of a moderate carbon content is very important such that it would lead to the formation of maximum sp3 Ge-C bonds alongside slight amounts of sp2 C-C and hydrogen bonds. For very low carbon concentrations, the existence of dominant Ge-Ge bonds would create the coating structure as germanium-like; the excessive rise of the carbon concentration promotes the undesirable graphite-like structures. In the optimum conditions, the hardness of the coating was obtained at 10.1 GPa. The coatings presented a very low residual stress (∼98-240 MPa) despite having suitable hardness.

In-plasma analysis of plasma–surface interactions

During deposition, modification, and etching of thin films and nanomaterials in reactive plasmas, many active species can interact with the sample simultaneously. This includes reactive neutrals formed by fragmentation of the feed gas, positive ions, and electrons generated by electron-impact ionization of the feed gas and fragments, excited states (in particular, long-lived metastable species), and photons produced by spontaneous de-excitation of excited atoms and molecules. Notably, some of these species can be transiently present during the different phases of plasma processing, such as etching of thin layer deposition. To monitor plasma–surface interactions during materials processing, a new system combining beams of neutral atoms, positive ions, UV photons, and a magnetron plasma source has been developed. This system is equipped with a unique ensemble of in-plasma surface characterization tools, including (1) a Rutherford Backscattering Spectrometer (RBS), (2) an Elastic Recoil Detector (ERD), and (3) a Raman spectroscopy system. RBS and ERD analyses are carried out using a differentially pumped 1.7 MV ion beam line Tandetron accelerator generating a beam at grazing incidence. The ERD system is equipped with an absorber and is specifically used to detect H initially bonded to the surface; higher resolution of surface H is also available through nuclear reaction analysis. In parallel, an optical port facing the substrate is used to perform Raman spectroscopy analysis of the samples during plasma processing. This system enables fast monitoring of a few Raman peaks over nine points scattered on a 1.6 × 1.6 mm2 surface without interference from the inherent light emitted by the plasma. Coupled to the various plasma and beam sources, the unique set of in-plasma surface characterization tools detailed in this study can provide unique time-resolved information on the modification induced by plasma. By using the ion beam analysis capability, the atomic concentrations of various elements in the near-surface (e.g., stoichiometry and impurity content) can be monitored in real-time during plasma deposition or etching. On the other hand, the evolution of Raman peaks as a function of plasma processing time can contribute to a better understanding of the role of low-energy ions in defect generation in irradiation-sensitive materials, such as monolayer graphene.

The Use of Chicken Feather Waste as an Adsorbent for Crude Oil Clean Up from Polluted Water

The present study aims to evaluate the use of chicken feather waste (CFW) as an absorbent for the removal of crude oil from crude oil polluted water (CPW) in comparison with commercial activated carbon (CAC) ) in Nigeria. Oil pollution, can be as a result of natural disaster like earthquake, volcanic eruption, hurricane etc., or as a result of man’s interference for example terrorism, oil bunkering, tanker and oil rig accidents. CAC have been use as adsorbent for crude oil removal from the water environment but very expensive, hence the need to develop cheaper and environment friendly adsorbents from some agricultural waste which could constitute nuisance in the environment. The pulverized chicken feathers were characterized using Rutherford Backscattering Spectrometer (RBS) and Scanning Electron Microscope (SEM) for elemental composition and the determination of surface morphology, respectively. The agricultural wastes used for this study was chicken feathers. The CFW was sourced from a local market at Ile-Ife, Osun State Nigeria, while commercial activated carbon was purchased from Uche-El Water Limited Company. The pulverized CFW was characterized using Scanning Electron Microscopy (SEM) and Particle-induced X-ray Emission (PIXE). Elemental composition of the CFW showed the presence of Na, Mg, Al, P, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Sr, Zr, Cd, Sn, Pb and Si within the range 12.8 - 22566.3 ppm with agglomeration of particle. The results of the scanning electron microscope clearly showed the surface texture and morphological characteristics of CFW. The efficiencies of adsorption increased with increasing initial concentration for the two adsorbents except initial concentration of 20/30 which decreased in the case of CAC. The adsorption efficiencies for all the initial concentrations for the adsorbents is significantly different (F=16.114; P=0.000) at confidence interval of 0.05. CFW showed greater adsorption efficiency of 99.95%, followed by CAC which showed an adsorption potential of 95.08% (P=0.577 > C.I=0.05). The adsorption efficiencies obtained for the chicken feather compare very well with the activated carbon and even better as the dosages of the chicken feather increased. The result of the study shows that chicken feathers is an efficient sorbent for the mopping of crude oil spill in water.

Elemental, structural and optical properties of nanocrystalline Zn 1−x Cu x Se films deposited by close spaced sublimation technique

Abstract The elemental composition, film thickness and concentration depth profiles of as-deposited and annealed Zn 1−x Cu x Se films were studied by the Rutherford backscattering spectrometer (RBS) technique. The films were deposited on glass substrates by close spaced sublimation (CSS) technique. As-deposited films of about 250–300 nm thickness were then annealed in air at temperatures of 200 °C and 400 °C for 1 h. Structural characterization including crystal structure, crystal orientation, stacking fault energy ( Ү SFE ) and surface morphology were carried out by using X-ray diffraction (XRD) and atomic force microscopy (AFM). XRD studies revealed that the fabricated films are polycrystalline with a zinc-blende structure and a strong (111) texture plane. Surface roughness was observed to be enhanced with annealing temperature with a decrease in stacking fault energy ( Ү SFE ). Spectroscopic ellipsometry has been utilized for the estimation of band gap energy (E g ) and dielectric constant (e 1 ). Band gap energy of the film increased with increasing annealing temperature while the dielectric constant decreased.

Influence of ion bombardment on structure and properties of TiZrN thin film

The study is focused on the characterization of TiZrN thin film by controlling the behavior of ion bombardment. Thin films are grown using radio frequency magnetron sputtering process on Si wafer. The negative bias voltage ranging from −20V to −130V was applied to the substrate. The ion current density increases rapidly as substrate bias is lower than −60V, then slightly increases as the critical value about −60V is exceeded. At the substrate bias of −60V, the ion current density is close to 0.56mA/cm2. The resistivity measured by four-point probe decreases from conditions −20V to −60V and then increases for substrate bias increases from −60V to −130V. The resistivity of TiZrN films is contributed from the packing factor. The N/TiZr ratios about 1 were measured by Rutherford backscattering spectrometer, and the packing factors of TiZrN films can also be obtained by the results of RBS. Field Emission scanning electron microscope (FEG-SEM) is used to characterize the thickness and structure of the deposited TiZrN film. X-ray diffraction (XRD) is used to determine the preferred orientation and lattice parameter. The precursor results of XRD show that all the coating samples exhibited (111) preferred orientation, and the hardness values of TiZrN films were ranging from 20 to 40GPa. To sum up the precursor studies, the TiZrN films which can improve the properties from TiN and ZrN is a new ceramic material with higher potential. Following the advance process and analysis research, the structure and properties can be correlated and as a reference for industry application.

The properties of Ru films deposited by remote plasma atomic layer deposition on Ar plasma‐treated SiO2

AbstractBy using remote plasma atomic layer deposition (ALD), ruthenium thin films were deposited on SiO2 using bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)2] as a Ru precursor and an ammonia plasma as a reactant. Different plasma treatments were applied, and the best results were obtained with the Ar plasma‐treated SiO2 surface. The initial transition region usually observed with Ru deposition before continuous film formation was present, and the number of ALD cycles required to obtain a continuous film was reduced to about 35 cycles on the Ar plasma‐treated SiO2 substrates. The transition region of Ru cluster growth on Ar plasma‐treated SiO2 was investigated with transmission electron microscopy (TEM). Most of the Ru clusters were larger and better crystallized on the Ar plasma‐treated SiO2 than on untreated SiO2. Also, Ru films deposited on the treated SiO2 exhibited a (002) preferred orientated structure with a film resistivity of about 10.26 µΩ‐cm. The growth rates of Ru after passing the transition region were similar on both the treated and untreated SiO2 at about 1.7 Å/cycles. From the Auger electron spectroscopy (AES) spectrum, a very low content of oxygen was observed in the Ru films. About 9% carbon was detected by a rutherford backscattering spectrometer (RBS).

Microstructure and corrosion resistance of nanocrystalline TiZrN films on AISI 304 stainless steel substrate

This study investigated the microstructure and properties of nanocrystalline TiZrN films on AISI 304 stainless steel substrate. TiZrN films were prepared by reactive magnetron sputtering based on the previous optimum coating conditions (substrate temperature, system pressure, nitrogen flow, etc.) for TiN and ZrN thin films. The composition ratio of TiZrN coatings were adjusted by changing the Zr target power, while keeping the Ti target power constant. Experiments were conduced to find the optimum composition with desired properties. The ratio of TiZrN composition was analyzed by x-ray photoelectron spectroscopy and Rutherford backscattering spectrometer. In terms of phase formation, there were two types of coatings that were considered: single-phase solid solutions of TiZrN and interlacing nuclei of TiZr in the matrix of TiZrN. The thickness of all TiZrN films as measured by the secondary ion mass spectroscopy was about 500 nm, and the composition depth profiles indicated that the compositions in the TiZrN films were uniform from the film surface to the 304 stainless steel substrate. The crystal structure of the TiZrN films was determined by x-ray diffraction using a M18XHF-SRA diffractometer with Cu Kα radiation. A diffraction peak of TiZrN (002) was observed between that of TiN (002) and ZrN (002); similarly, a diffraction peak of TiZrN (111) was observed between that of TiN(111) and ZrN(111), respectively. The corrosion resistance of the TiZrN film deposited on the 304 stainless steel has been investigated by electrochemical measurement. The electrolyte, 0.5M H2SO4 containing 0.05M KSCN, was used for the potentiodynamic polarization. The potentiodynamic scan was conducted from −800 to 800 mV standard calomel electrode (SCE).

Thickness and component distributions of yttrium-titanium alloy films in electronbeam physical vapor deposition

Thickness and component distributions of large-area thin films are an issue of international concern in the field of material processing. The present work employs experiments and direct simulation Monte Carlo (DSMC) method to investigate three-dimensional low-density, non-equilibrium jets of yttrium and titanium vapor atoms in an electron-beams physical vapor deposition (EBPVD) system furnished with two or three electron-beams, and obtains their deposition thickness and component distributions onto 4-inch and 6-inch mono-crystal silicon wafers. The DSMC results are found in excellent agreement with our measurements, such as evaporation rates of yttrium and titanium measured in-situ by quartz crystal resonators, deposited film thickness distribution measured by Rutherford backscattering spectrometer (RBS) and surface profilometer and deposited film molar ratio distribution measured by RBS and inductively coupled plasma atomic emission spectrometer (ICP-AES). This can be taken as an indication that a combination of DSMC method with elaborate measurements may be satisfactory for predicting and designing accurately the transport process of EBPVD at the atomic level.

Deposition of TiC on γ-TiAl Alloys by Directly Applying Voltages

Two γ-TiAl alloys, Ti-47Al-2Nb-2Cr (MJ12) and Ti-47Al-2Nb-2Mn-0.8TiB2 (MJ47), were pressed in C powder to form rods and carburized by directly applying electrical power through them at 274.3 ± 26.4 W, 80 A for MJ12 and at 293.4 ± 16.8 W, 80 A for MJ47 in Ar atmosphere. The alloys were analysed using an x-ray diffractometer (XRD), a scanning electron microscope (SEM) equipped with an energy dispersive x-ray (EDX) analyser and a Rutherford backscattering spectrometer (RBS) incorporated with NUSDAN solfware. Knoop hardness and wear resistance were improved and found to be in accord with the analytical results.

Mössbauer studies of the Cr doped ordered perovskite

AbstractThe Cr doped ordered perovskite powder of Sr2Fe0.93Cr0.07MoO6 has been prepared by a solid‐state reaction method. The chemical composition and the crystalline structure of the sample were confirmed with the Rutherford backscattering spectrometer spectrum and X‐ray diffraction pattern analysis. The crystalline structure was determined to be tetragonal with lattice parameters a0 = 5.572 Å and c0 = 7.900 Å, respectively. The magnetic properties of the Sr2Fe0.93Cr0.07MoO6 have been studied by the vibrating sample magnetometer and the Mössbauer spectroscopy. The saturation magnetization and the coercive force were 26.5 emu/g and 101.2 Oe at room temperature. Mössbauer spectra measurements of the Sr2Fe0.93Cr0.07MoO6 have been taken at various temperatures ranging from 15 to 450 K. Analysis of Mössbauer spectra has considered with next nearest‐neighbour interactions and the anisotropic hyperfine field fluctuation. The anisotropic field fluctuation of +H (P+ = 0.85) is greater than that of −H (P− = 0.15). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Tribological Property of CeO2 Films Prepared by Ion-Beam-Assisted Deposition

Cerium oxide (CeO2) films were prepared by ion-beam-assisted deposition (IBAD). The films were synthesized on WC–Co and Si(100) substrates by depositing CeO2 vapor under simultaneous bombardment of O2, Ar and Xe ions in the energy range of 1.0 to 5.0 keV. The elemental composition ratio (O/Ce) measured by Rutherford backscattering spectrometer (RBS) was in the range of 1.9 to 2.9, which was considerably higher than that expected from the stoichiometry. The X-ray diffractometry (XRD) patterns of CeO2 films prepared using O2, Ar and Xe ion beams exhibited a single-phase CaF2 structure, which is typical of CeO2. By increasing the transport rate ratio of the ions to CeO2 vapor, the morphology of the specimens prepared using O2 and Xe ion beams changed from a columnar grain to a granular one at transport ratios of 1.0 and 0.33, respectively. The defect density produced on the CeO2 film surface by ion irradiation was elucidated by Monte-Carlo simulation, leading to the result that the morphology change from columnar to granular is brought about at a threshold value in the defect density induced by ion bombardment. It was also been determined that the granular grain films have the very low friction coefficients of 0.15 at room temperature and 0.035–0.040 at 200°C, respectively.

Mechanical properties of TiN thin film coatings on 304 stainless steel substrates

Titanium nitride (TiN) film was deposited on 304 stainless steel using a hollow cathode discharge ion-plating (HCD-IP) technique. Film thickness and N/Ti ratio were controlled. The depth profile of the composition was determined by secondary ion spectroscopy (SIMS). The results showed that the compositions of the films were uniform for the films deposited at the same deposition conditions. The purpose of this study is to investigate the variation of structure and mechanical properties of the TiN films with different film thickness. The preferred orientations of TiN films were determined using X-ray diffraction (XRD). The dominant preferred orientation of the TiN coatings for the deposition conditions was (111), especially for the films thicker than 1 μm. The residual stress of the TiN films was also measured by XRD using sin 2 Ψ method. The residual stress was ranging from −5.93 to −2.70 GPa, varying with film thickness. Hardness of the films was measured by nanoindentation. The hardness values were ranging from 14.9 to 33.6 GPa, increasing with the film thickness. The ultimate interfacial shear stress between TiN/304SS was determined by in-situ strip tension of the TiN-coated specimens in a scanning electron microscope (SEM) chamber. The limiting thickness for the effective measurement of interfacial shear strength by the in-situ strip tension method is close to 0.5 μm. N/Ti ratios of the thin films were all at 0.8 measured using both X-ray photoelectron spectrometer (XPS) and Rutherford backscattering spectrometer (RBS). The packing factors of TiN films, calculated from the results of RBS, were 0.62–0.99, increasing with film thickness and leveling off at a thickness above 1.2 μm.

Corrosion behavior of TiN-coated 304 stainless steel

Titanium nitride (TiN) was deposited on AISI 304 stainless steel using a hollow cathode discharge ion-plating technique. Corrosion behavior of the TiN-coated stainless steel was studied on the specimens with controlling TiN film thickness. The composition depth profiles of TiN films were determined using a secondary ion mass spectrometer. The N/Ti ratios were measured using both X-ray photoelectron spectrometer and Rutherford backscattering spectrometer (RBS). From the results of RBS, packing factors of the TiN films can be obtained. The corrosion resistance was evaluated by standard salt spray test, and by potentiodynamic polarization scan of the specimens in two kinds of solutions, 5% NaCl and 1 N H 2SO 4+0.05 M KSCN, respectively. The surface morphology of the specimens after corrosion tests was observed using both FEG-SEM and optical microscope. The corrosion resistance was correlated to film thickness, packing factor, and thickness×packing factor. There is a good agreement between the results of salt spray tests and potentiodynamic polarization scans. In the case of 5% NaCl solution, the critical thickness is about 0.7 μm, while in 1 N H 2SO 4+0.05 M KSCN, the critical thickness is about 0.3 μm. As the film thickness was smaller than the critical thickness, the corrosion current increased abruptly. It is also found that when the value of thickness×packing factor >0.6, there is only minor increase in corrosion resistance for the TiN-coated specimen in 5% NaCl solution. This index becomes 0.3 for specimen in 1 N H 2SO 4+0.05 M KSCN.

Deposition of TiN thin films on Si(100) by HCD ion plating

Titanium nitride (TiN) films were deposited on Si(100) substrates using a hollow cathode discharge ion plating (HCD-IP) technique. Based on previous experimental results, the optimum deposition conditions were chosen. The thickness of the TiN film and the angle between the specimen surface and the evaporating source (coating angle) were selected as the variable parameters. The purpose of this study is to investigate the effect of these two processing parameters on the properties of TiN films. After deposition, the thin film structure was characterized by X-ray diffraction (XRD), cross-sectional transmission electron microscopy (XTEM), and field-emission-gun scanning electron microscopy (FEG-SEM). N/Ti ratios of the thin films were determined using both X-ray photoelectron spectrometer (XPS) and Rutherford backscattering spectrometer (RBS). The resistivity of the TiN films was measured by a four-point probe. The hardness of the thin films was obtained from nanoindentation tests. An atomic force microscope (AFM) was used to measure the roughness of the thin films. The results showed that (111) was the dominant preferred orientation in the TiN films for most of the deposition conditions and for all coating angles, especially for film thicknesses greater than 1 μm. Hardness values of TiN films were approximately 28 GPa for film thicknesses close to 0.5 μm and above, and did not vary with the coating angle. The hardness can be correlated to the (111) preferred orientation of the TiN film. The hardness increased with the (111) texture coefficient and leveled off as the texture coefficient approached 1. The packing factor had a linear relationship with the film thickness. Resistivity decreased with increasing thickness and increasing packing factor for all coating angles. At a similar thickness or packing factor, specimens coated at angles different from 0° had a much higher resistivity than those coated at 0°.

Effect of pinhole Au/Ni/Cu substrate on self-alignment of advanced packages

The self-alignment of advanced packages (μBGA) on both non-pinhole and pinhole Au/Ni/Cu pads has been discussed. It is found that a slight reduction of self-alignment of the packages using pinhole pads occurs. Rutherford backscattering spectrometer (RBS) results suggest that this reduction should not be attributed to the oxide formation of the surface or interface layer in the Au/Ni/Cu pads. The solder wetting experiments show that slow spreading of molten solder on pinhole pads may result in a reduction of effective board pad surface area that can be wetted. This will reduce the restoring force of the solder joints, and thus causing a less better self-alignment of the packages using pinhole pads. Oxidation of nickel at the exposed area and Au/Ni interface is observed to occur by direct exposure of substrate pads through pinholes during aging. The solder wetting of the aged pads has been described. For flux reflow soldering, the aging of the pads seems to have no serious effect on the self-alignment of the package. However, it is found from the peel-off test that a few solder joints of the samples after reflow have weak adhesion strength at the solder and aged pinhole pad interface. The mechanism for this weak adhesion strength has been proposed.

Ultra-Thin TaN Films As Diffusion Barriers For Cu Metallization

ABSTRACTThe Cu metallization in future VLSI technology requires a liner or diffusion barrier. We have studied TaN thin Films of thickness from 5 nm to 3 nm as the diffusion barrier. We deposited sandwiched TaN/Cu/TaN thin films on oxidized Si wafers, annealed them in air with ramping temperature, and measured in-situ resistance changes. Scanning and transmission electron microscopes were used to characterize the surface and microstructure of the thin films and Rutherford backscattering spectrometer (RBS) was used to profile the elemental composition and after oxidation. The oxidation of the Cu sandwiched between TaN films of 5, 10, 20, and 30 nm occurs at 300, 400, 450 and 475°C, respectively. The activation energy of oxidation of Cu with the TaN barrier of 10, 20, and 30 nm are 1.73, 2.13, and 2.26 eV, respectively, but the 5 nm TaN was not calculated due to large data scattering. For comparison, the oxidation temperature and activation energy for bare Cu films in air are 250°C and 0.74 eV, respectively. It suggests that 20 nm of TaN is quite effective as a barrier layer. However, the reaction between Cu and the underlying SiO2/Si layers was also detected in RBS; this may arise as another serious reliability criterion to the system.

Application of SiO 2 aerogel film with low dielectric constant to intermetal dielectrics

SiO 2 aerogel film was characterized from its structural and chemical viewpoints. High porosity of material was measured and compared to thermally grown SiO 2 film by Rutherford backscattering spectrometer (RBS). Porous film nature was re-evaluated as enhanced etch rate with high density CHF 3-plasma. Detailed observation of microstructure revealed that constituent particles of which the size is in the diameter range of 10–30 nm are cross-linked to build up the skeletal network. Large interior surface coverage, such as alkoxyl group and hydroxyl group were investigated using X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FT-IR) for their chemical states. The improved electrical properties of SiO 2 aerogel after annealing at 450°C were interrelated with the thermal evolution of these surface species, where surface alkoxyl plays the dominant role over surface hydroxyl. Furthermore, good gap-filling and planarization ability on 0.8 μm line and space trench as other requirements for intermetal dielectric application was demonstrated.

Modification of Fracture Energy of Niobium/sapphire Interface By Impurity Doping

ABSTRACTThe effect of interface composition on the fracture energy and fracture toughness of the niobium/sapphire system was studied. Niobium films with thickness of 100 nm were deposited on (0001) sapphire substrates by physical vapor deposition (PVD). The interface was doped with silver to reduce the interfacial cohesion. The amount of silver ranged from less than 2.1 monolayers to 6.4 monolayers as measured by Rutherford backscattering spectrometer (RBS). The microscratch test was used in determining the interfacial fracture energy and the interfacial fracture toughness. Both interfacial fracture energy Gc and fracture toughness Kc decrease non-linearly with the amount of silver, and level off for samples with larger silver thickness ( > 4.2 monolayers). The values of interfacial fracture energy range from 3.43 J/m2 - 9.20 J/m2 for the sample doped with 2.1 monolayer silver (sample B) to 0.05 J/m2 - 0.5 J/m2 for samples with silver levels above 4.2 monolayers (samples D and E). The corresponding fracture toughnesses are 0.80 MPa-m½ - 1.29 MPa-m½ for sample B and 0.09 MPa-m½ - 0.30 MPa-m½ for samples D and E.

Spectroscopic ellipsometry characterization of silicon-on-insulator materials

The wide applicability of spectroscopic ellipsometry (SE) to characterize non-destructively silicon-on-insulator materials is illustrated with a number of case studies. SE allows the determination of not only the optical properties of single layers as a function of the wavelength but also their thickness with great accuracy. When reliable reference values for the complex refractive indices of the components of a multilayer system are available, information on layer thicknesses, interface roughness and even composition of mixed layers can be obtained with remarkable accuracy. In such cases SE can act as a one-dimensional optical high resolution microscope and even to some extent as an optical “Rutherford backscattering spectrometer”.