Element Depth Profiling

The absolute sensitivity factors Sx must be determined for this procedure by integrating intensities over time while sputtering suitable pure element samples and determining the crater volume for HF-plasma SNMS the weight loss can also be measured. 

3 Electron-impact (El) Secondary Neutral Mass Spectrometry (SNMS) 131 

Recent applications of e-beam and HF-plasma SNMS have been published in the following areas aerosol particles [3.77], X-ray mirrors [3.78, 3.79], ceramics and hard coatings [3.80-3.84], glasses [3.85], interface reactions [3.86], ion implantations [3.87], molecular beam epitaxy (MBE) layers [3.88], multilayer systems [3.89], ohmic contacts [3.90], organic additives [3.91], perovskite-type and superconducting layers [3.92], steel [3.93, 3.94], surface deposition [3.95], sub-surface diffusion [3.96], sensors [3.97-3.99], soil [3.100], and thermal barrier coatings [3.101]. 

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Rutherford Backscattering (RBS) provides quantitative, nondestructive elemental depth profiles with depth resolutions sufficient to satisfy many requirements however, it is generally restricted to the analysis of elements heavier than those in the substrate. The major reason for considering depth profiling using FIXE is to remove this restrictive condition and provide quantitative, nondestructive depth profiles for all elements yielding detectable characteristic X rays (i.e.,Z> 5 for Si(Li) detectors). 

Fig. 3.17. Multi-element depth profile of a B 0 5 10 15 20 25 layer in Si performed with 600-eV SF5 sputtering...

SNMS is suitable for quantitative element depth profiling of metallic and electrically insulating samples. Laser-SNMS enables the additional acquisition of 2D element distributions with HF-plasma SNMS bulk analysis is also feasible. 

TOF-SIMS can be applied to identify a variety of molecular fragments, originating from various molecular surface contaminations. It also can be used to determine metal trace concentrations at the surface. The use of an additional high current sputter ion source allows the fast erosion of the sample. By continuously probing the surface composition at the actual crater bottom by the analytical primary ion beam, multi element depth profiles in well defined surface areas can be determined. TOF-SIMS has become an indispensable analytical technique in modem microelectronics, in particular for elemental and molecular surface mapping and for multielement shallow depth profiling. 

The use of nuclear techniques allows the determination of C, N, H, O, and heavier contaminants relative fractions with great accuracy, and of the elements depth profile with moderate resolution (typically 10 nm). Rutherford backscattering spectroscopy (RBS) of light ions (like alpha particles) is used for the determination of carbon and heavier elements. Hydrogen contents are measured by forward scattering of protons by incident alpha particles (ERDA) elastic recoil detection analysis [44,47]. 

Elemental Depth Profiling Analysis. An important aspect of a surface specific analysis is that it does not directly contrast the surface composition with that of the... 

Ultra-vioteFphotoelectron spectroscopy (UPS) UV-hgH Valence electrons Qualitative and quantitative analysis of elements Depth profiling... 

Backscattering of noble gas ions at solid surfaces is a useful tool to obtain elemental depth profiles. The two main ion spectroscopies work with different primary... 

It is clear from above that beside the conventional usage of SIMS for elemental depth profiling in semiconductors, it has a potential of becoming a powerful tool to spatially map two cind/or three dimensional distribution of inpurity elements. However, spatial resolution at present is rather limited (>1y m) especially if the technique has to be extended to sub micron geonetries. Transmission Electron Microscopy... 

X-ray analysis, including Rutherford backscattering, to understand the crystal structure and to obtain elemental depth profiles, to gain insight into the conductivity mechanism. 

Quantitative elemental depth profiles can be obtained by collecting XPS spectra at different emission angles, which have differing depth sensitivities, and analysing... 

Figure 7. Elemental depth profile after one hour plasma treatment of nylon 6/7.5% layered silicate nanocomposites. (1. oxygen, 2. silicon, 3. aluminum, 4.

Nuclear reaction analysis (NRA) and elastic recoil detection (ERD) are part of the suit of ion beam analysis (IBA) techniques. They are commonly used for the elemental depth profiling of materials in a wide range of fields, e.g., from biological and medical to the semiconductor industry. 

With conventional ERD, all elements lighter than the incident ion are detected and all the other elements are blocked by the stripper foil. The use of a heavier mass incident ion beam, allows a multitude of other different elements to be recoiled forward and detected. In the conventional ERD, the different elemental spectra superimpose on each other and it becomes difficult to sort the separate masses so as to provide unambiguous data on the different elemental depth profiles. 

The FIs peak at 691 eV of the C-F bonds in CF (Figure 14c) supports the presence of binder in the cross-section plane of the electrode. During sputtering, the intensity of this peak falls dramatically and the LiF bond becomes the dominating feature in the FIs spectrum. The thickness of the SEI formed on the basal plane of the carbon electrode seems to be lower than that on the cross section. This conclusion can be drawn from the elemental depth profiles, where concentrations of fluorine and lithium are halved after 20 minutes of sputtering in the basal SEI, but almost does not change in the SEI on the cross section (unpublished data). 

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