Rutherford Backscattering Spectrometry RBS

The intensity of a peak in RBS is determined by the cross section o for scattering. At MeV energies, the helium ion penetrates deeply into the atom and approaches the nucleus of the target atom to within 10 4 nm, i.e. well within the radius of the K-electron shell. This means that the scattering event depends only on the Coulomb repulsion between the two nuclei, whereas screening by the electrons (which is important in LETS) plays no role. Thus the scattering cross section is a 

Z is the atomic number, equal to the number of protons of an element 

We illustrate the use of RBS with a study on the sulfidation of molybdenum hydrodesulfurization catalysts supported on a thin layer of Si02 on silicon [21], As explained in connection with the SIMS experiments on this model system (Fig. 4.8), the catalyst is sulfided by treating the oxidic Mo03/Si02 precursor in a mixture of H2S and H2. RBS is used to determine the concentrations of Mo and S. 

The bottom spectrum in Fig. 4.16 is that of the fresh MoCVSi02/Si( 100) model catalyst a part is shown enlarged. The peak at 3.4 MeV has a kinematic factor of about 0.85. As the scattering angle is 170°, the reader can use Fig. 4.14 to verify that this peak belongs to Mo. In the same way one may check that the continuum below E = 2.3 MeV is due to 28Si. Note that small peaks due to the Si isotopes at 29 and 30 amu are just visible as well. The structure around 2 MeV is caused by non- 

Rutherford scattering behavior. The Mo intensity corresponds to a loading of 1,2 0. MO15 atoms/cm2. It would be difficult to obtain such an accurate number from any other technique in this concentration range. 

The intensity of a peak in RBS is determined by the cross-section a for scattering. At MeV energies, the helium ion penetrates deeply into the atom and approaches the nucleus of the target atom to within 10 4 nm - that is, well within 

Other successful applications of RBS on flat supported model catalysts include systems such as RI1/AI2O3/AI [47, 48] and Zr02 [49], PtCo [50] and Cr on Si02/ Si(100) [51]. The reason why RBS is so effective with these systems is that they consist of heavy elements on top of a lighter support, with the fortunate consequence that peaks due to the elements of interest appear on a background of almost zero. 

Rutherford scattering refers to the deflection of an incoming, moving nucleus (typically a light ion such as H , He , or He with a kinetic energy in the MeV range) due to interaction with an atomic nucleus at rest and more or less firmly held in place in the sample. Ions scattered further into the sample are implanted and evade detection, but ions backscattered in the process can be detected once they leave the sample surface. Hence, the name Rutherford backscattering spectrometry (RBS) for this technique. 

---

Rutherford Backscattering Spectrometry (RBS) in-depth concentration profiles were determined by Rutherford backscattering spectrometry by using a 2.2 MeV He beam at INFN-Legnaro National Laboratories, Legnaro-Padova (Italy). 

Rutherford backscattering spectrometry (RBS) which analyses the elastic scattering of the particle beam from the target nuclei. Most RBS analyses use less than 2.2 MeV He++ beams. 

The samples were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, 57Fe Mossbauer spectroscopy [2] and Rutherford backscattering spectrometry (RBS). 

Pritzkow et al 46 described the application of surface and near-surface analytical methods such as ICP-IDMS (after dilution of layer), Rutherford backscattering spectrometry (RBS) and instrumental... 

Rutherford Backscattering Spectrometry (RBS) is a non-destructive (sub)-surface analysis technique for solid systems. In principle atomic composition and depth distribution can be obtained for a sub-surface layer of a few microns. 

Glancing angle (a=80 ) Rutherford backscattering spectrometry (RBS) with a 2.0 MeV He" beam was used to obtain the depth-resolved elemental composition of the films. In order to obtain sufficient counting statistics, and at the same time minimize beam-induced damage, each spectrum was accumulated from 20 different spots on the sample. The He ion beam dose was kept below 1 C/cm per spot. Spectral simulation was performed using the computer code RUMP (14). 

The remaining work discusses two techniques in thin film analysis, Rutherford backscattering spectrometry (RBS) and X-ray diffractrometry with emphasis on strain measurements. Rutherford backscattering spectrometry is illustrated with analysis of silicide formation as an example of thin film reactions. Silicon-germanium-carbon films serve as an example of strain calculations. 

The basic experimental equipment is the same as in Rutherford backscattering spectrometry (RBS), but it is usual to use the glancing geometry with very small incident angles. 

Surface/interfaoe chemistry X-ray photoelectron spectros copy (XPS, ESCA) Auger electron spectroscopy (AES) Secondary ion mass spectros copy (SIMS) Rutherford backscattering spectrometry (RBS) Ultraviolet photoelectron spectroscopy (UPS) Infrared (IR) spectroscopy Raman spectroscopy... 

FIGURE 25.10 Rutherford backscattering spectrometry (RBS) of a reaction between NiO and AI2O3 substrates for different surface orientations. 

---