Quantitative depth-profiling

Three common uses of RBS analysis exist quantitative depth profiling, areal concentration measurements (atoms/cm ), and crystal quality and impurity lattice site analysis. Its primary application is quantitative depth profiling of semiconductor thin films and multilayered structures. It is also used to measure contaminants and to study crystal structures, also primarily in semiconductor materials. Other applications include depth profilii of polymers, high-T superconductors, optical coatings, and catalyst particles. ... 

Optical/antireflective Quantitative depth profiling of multilayered stacks coatings (Si02, Hf02, Ti02, Sn02, InSn Oj, etc.)... 

Figure 6 Quantitative depth profile of the minor alloying elements Cu and Si in Al met-...

In contrast with the dc source, more variables are needed to describe the rf source, and most of these cannot be measured as accurately as necessary for analytical application. It has, however, been demonstrated that the concept of matrix-independent emission yields can continue to be used for quantitative depth-profile analysis with rf GD-OES, if the measurements are performed at constant discharge current and voltage and proper correction for variation of these two conditions are included in the quantification algorithm [4.186]. 

If the rf source is applied to the analysis of conducting bulk samples its figures of merit are very similar to those of the dc source [4.208]. This is also shown by comparative depth-profile analyses of commercial coatings an steel [4.209, 4.210]. The capability of the rf source is, however, unsurpassed in the analysis of poorly or nonconducting materials, e.g. anodic alumina films [4.211], chemical vapor deposition (CVD)-coated tool steels [4.212], composite materials such as ceramic coated steel [4.213], coated glass surfaces [4.214], and polymer coatings [4.209, 4.215, 4.216]. These coatings are used for automotive body parts and consist of a number of distinct polymer layers on a metallic substrate. The total thickness of the paint layers is typically more than 100 pm. An example of a quantitative depth profile on prepainted metal-coated steel is shown as in Fig. 4.39. 

Fig. 4.39. Quantitative depth profile of a commercial prepainted metal-coated steel 60 sample (a) as recorded ...

Surface and quantitative depth profile (QDP) analysis of multimatrix materials (nm to 100 rm)... 

Baudoin etal. [168,169] first presented qualitative depth profiles of lacquer and polymer coatings by means of r.f. GD-OES. Quantitative depth profiles were successively obtained by Payling et al. [170] on prepainted metal coated steel. Samples comprised a (rutile) pigmented silicone-modified polyester topcoat over a polymer primer, on top of an aluminium-zinc-silicon alloy coated steel substrate. With GD-OES in r.f. mode, it was possible to determine the depth profile through the polymer topcoat, polymer primer coat, metal alloy coating, and alloy layer binding to the steel substrate with a total depth of 50 im, all in about 60 min on the one sample. GD-OES depth profiles of unexposed and weathered silicone-modified polyesters were also reported [171]. Radiofrequency GD-OES has further been used to... 

Quantitative depth profiling using polyatomic MCs+ and MCs2+ ions instead of atomic ions M= ions is well established in surface analysis using SIMS. The MCs+ technique, which reduces matrix effects significantly, was proposed by Gao in 1988.100 The formation of MCs+ has been explained by the recombination of sputtered neutral atoms (M) with... 

Instruments based on GD-MS coupling have been employed most commonly for the quantitative analysis of trace and ultratrace amounts in high-purity materials. However, it has been demonstrated that, as in GD-OES, quantitative depth profile analysis by GD-MS is possible [33]. At present, a GD-MS prototype which allows the depth quantification of thin layers on conducting or insulating materials is being developed for commercial purposes [34]. 

M. Vazquez Pelaez, J. M. Costa-Fernandez, R. Pereiro, N. Bordel and A. Sanz-Medel, Quantitative depth profile analysis by direct current glow discharge time of flight mass spectrometry, J. Anal. At. Spectrom., 18,2003, 864-871. 

Figure 39 Quantitative depth profile on III-V compound structure using MCs+ molecular ions. (From Ref. 128.)...

We conducted some ERD measurements to study the hydrogen depth distribution of Ni(ya-Al203 samples after annealing in steam (fig. 7). A 2.2 MeV 4He+ beam was used and a 8.9 Jim Mylar foil. The recoil angle was 36q, and the angle between the beam direction and the sample normal was 72D. It is evident that ERD is a very powerful technique, since it is one of the few methods capable of quantitative depth profiling light elements in a heavy matrix. 

The hardening and embrittlement of polyimides by ion implantation has been also studied (Pivin, 1994). Nanoindentation tests performed using a sharp diamond pyramid of apical angle 35° provided very quantitative depth profiles of microhardness in polyimides implanted with C, N, O, Ne or Si ions. In all cases the microhardness increased steeply when the amount of deposited energy reached the order of 20 eV atom". For energies of 200 eV atom" the polymer is transformed into an amorphous hydrocarbon and the microhardening factor saturates at a value of 13-20. However, the carbonized layer is poorly adherent, as is evidenced by reproducible discontinuities in the depth vs load curves, when the indenter tip reached the interface. 

Figure 7.46 A GD depth profile of a titanium nitride coating on steel. TiN is a hard, brittle material often used to modify the surface of steel. The quantitative depth profile software on this system can verify the stoichiometry of the coating layer. [Courtesy of LECO Corporation, St. Joseph, MI (www.leco.com).]...

SIMS is used for quantitative depth profile determinations of trace elements in solids. These traces can be impurities or deliberately added elements, such as dopants in semiconductors. Accurate depth prohles require uniform bombardment of the analyzed area and the sputter rate in the material must be determined. The sputter rate is usually determined by physical measurement of the crater depth for multilayered materials, each layer may have a unique sputter rate that must be determined. Depth prohle standards are required. Government standards agencies like NIST have such standard reference materials available for a limited number of applications. For example, SRM depth profile standards of phosphorus in silicon, boron in silicon, and arsenic in silicon are available from NIST for calibration of SIMS instmments. P, As, and B are common dopants in the semiconductor industry and their accurate determination is critical to semiconductor manufacture and quality control. 

Kubota, N., Hayashi, S. (2008) Application of resonant laser postionization SNMS for quantitative depth profiling in stainless steel with oxide film. Appl Surf. Sci,255, 1516-1518. 

Quantitative depth profiling analysis of CaroUngian denari and gros of Saint Louis... 

FIGURE 40.18 Depth profiles by laser secondary neutral mass spectrometry (laser SNMS), secondary ion mass spectrometry (SIMS) with Ar and 02 primary ions, and Auger electron spectroscopy (AES) of implanted boron. Reprinted from Higashi, Y., Quantitative depth profiling by laser-ionization sputtered neutral mass spectrometry (1999) Spectrochimica Acta Part B Atomic Spectroscopy, 54(1), 109-122. Copyright (1999), with permission from Elsevier Science. 

Vanhove, N., Elevens, R, Vandervorst, W. (2008) Towards quantitative depth profiling with high spatial and high depth resolution. Applied Surface Science, 255, 1360-1363. 

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