Small Area X-ray Photoelectron Spectroscopy Research Articles

Small area X-ray photoelectron spectroscopy (SAXPS) analysis of microscopic contamination in semiconductor materials and processes

Microscopic contaminants occurring in the semiconductor manufacturing environment have been analysed using SAXPS. The molecular information obtained can be utilised to successfully identify and locate the sources of contamination. A description of the working principles of SAXPS and case studies in wafer fabrication and packaging assembly are presented.

Small‐area XPS and XAES study of the iron ore smelting process

AbstractThe iron ore deposit of Kerry (north‐western Syria) has been sampled; by means of the combined use of small‐area x‐ray photoelectron spectroscopy (SA‐XPS), small‐area x‐ray induced Auger electron spectroscopy (SA‐XAES), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), differential thermal analysis (DTA) and thermal gravimetric analysis (TGA), the smelting process of the most iron‐rich ore has been studied under a CO atmosphere up to 1570 K. Attention has been focused on the chemical aspects involvéd during the reduction of the iron ore and on the chemical composition of the non‐metallic compounds, i.e. the slags, that result from the smelting process. Furthermore, this information has been compared with that obtained from early iron metallurgy slags and artefacts found in north‐western Syria in order to locate the geographical source of the iron ore exploited during the early Iron Age in this region.

Small‐area XPS investigation on ion‐induced chemical modifications during depth‐profiling of an AlxGa1−xas/gaas structure

AbstractDepth profiling by argon ion sputtering was carried out on an Al0.3Ga0.7As/GaAs layered structure, using different ion‐beam energies (up to 5 keV) and keeping constant the ion current density. When the steady state condition was reached in the ternary layer, in order to investigate the ion‐induced chemical modifications, angle resolved small‐area x‐ray photoelectron spectroscopy (SA‐XPS) investigations were carried out on the bottom of the crater resulting from the ion‐beam erosion. In order to study the different regions of the damaged layer, attention was focused on the As 3d, Ga 3d and Al 2p signals as well as on the As 2p3/2 and Ga 2p3/2 peaks, which are spread over an energy range about 1000 eV wide and therefore photoemitted from different depths. The results show the different ion‐induced effects on the chemical composition of the Al0.3Ga0.7As layer, such as arsenic preferential sputtering, aluminium Gibbsian segregation and further, the formation of elemental species, as a function of the Ar+ energy.

Surface characterization of ceramic brackets: A multitechnique approach

The purpose of this study was to investigate the microstructure and bonding mechanisms for four types of ceramic brackets by using information from several methods. Two of the bracket types provided exclusively micromechanical retention as a bonding mechanism, with the use of microspheres or microcrystals to achieve a rough structure for the bracket base. A silane layer that provided chemical adhesion was found to cover the bases of the two other types of brackets; one type also used central regions of increased roughness to provide additional micromechanical retention. Polarized-light optical microscopy showed that the silane layer was not continuous. Small area x-ray photoelectron spectroscopy analysis (SAXPS) of the silane layer was consistent with the presence of gamma-methacryloxypropyl trimethoxysilane. The study of the ceramic bracket bases revealed a wide variety in composition, structure, morphologic condition, and coating treatment that implies different bonding mechanisms to orthodontic adhesives.

Quantitative analysis of Al xGa 1- xAs/GaAs multiquantum wells by means of AES depth profiling and small area XPS

By means of Auger electron spectroscopy (AES) depth profiling and small area X-ray photoelectron spectroscopy (XPS), the chemical composition of the Al x Ga 1- x As layer in a series of reference Al x Ga 1- x As/GaAs (0.15 <x< 0.40) multiquantum wells (MQW) and the sharpness of the hetero-interface, have been studied. For a particular set of experimental conditions, a calibration curve has been obtained for the aluminum content, that shows a linear relationship between AES data and chemical composition deduced from both MBE growth parameters and double crystal diffraction. This calibration curve has been used to determine the chemical composition of a nominal Al 0.3Ga 0.7As/GaAs MQW. Furthermore, the abruptness of the change in composition at the interface between Al 0.30Ga 0.7As and GaAs layers has been well characterized and an ultimate depth resolution of 5 nm has been achieved for a sputtering ion energy of 1 keV.

Microchemical investigation of early iron metallurgy slags

A group of slags, dating back to Iron Age II (Aramean period, 800-720 B.C.), that appeared to be iron-smelting by-products, have been found at Tell Afis (North-Western Syria). The microchemistry of these materials has been studied by means of small-area X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), scanning electron microscopy (SEM), electron-probe microanalysis (EPMA) and optical microscopy (OM). The results indicate that the slags can be associated with an iron-smelting process and show the presence of large amounts of Fe(II) and Fe(III) oxides and hydroxides mixed with different glassy and crystalline silicon compounds. The latter consist essentially of quartz and various silicates, such as wollastonite, melilite, Mg[SiO4] or Mg[SiO6] compounds and other complex aluminosilicates. This chemical information is used to elucidate some aspects of the early ironmaking process.

Application of Surface and Bulk Analytical Techniques for the Study of Iron Metallurgy Slags at Tell Afis (N-W Syria)

ABSTRACTBy a combined use of small area X-ray photoelectron spectroscopy (SA-XPS),X-ray induced Auger electron spectroscopy (XAES), scanning electron microscopy (SEM) and electron probe for microanalysis (EPMA), the microchemistry of a group of slags from Tell Afis (North-Western Syria), dating back to Iron Age II (750 B.C.), have investigated. The results show and localize the presence of different iron oxides and hydroxides as well of various glassy and crystalline silicates, whose chemical structure and morphology have determined.

Dose-dependent cesium ion beam damage effects on chemically modified poly(methyl methacrylate) films using secondary ion mass spectrometry and x-ray photoelectron spectroscopy

The Cameca IMS-3f ion microscope was used to obtain negative SIMS spectra of poly(methyl methacrylate) (PMMA) and chemically modified PMMA films to assess its ability to provide surface structural information from organic samples. Negative ion spectra generated by Cs/sup +/ bombardment produced structurally specific fragment ions, particularly for Cs/sup +/ doses of < 1 X 10/sup 15/ ions/cm/sup 2/. At larger doses, the progressive degradation of the native polymer structure was reflected by an increasing hydrocarbon-like fragmentation pattern. The primary ion dose dependence of various secondary ion intensities, as influenced by beam damage effects, was established. Small-area X-ray photoelectron spectroscopy (XPS) was used to confirm these results. The PMMA was chemically modified with pentafluorobenzaldehyde (PFBA) and dissolved in a solvent in which the polymer was insoluble, to provide tag molecules at the polymer's surface. Although XPS indicated that only 6% of the near-surface ester side chains were labeled with PFBA, tag-related molecular fragment ions such as C/sub 6/F/sub 5//sup -/ exhibited strong intensities in the immediate surface region. 24 references, 7 figures, 5 tables.