Rutherford Backscattering Spectroscopy
BINA's new Rutherford Backscattering Spectrometry system (RBS) applies an exceptional technique to chemically analyze surface layers in three dimensions, leaving samples unharmed. The RBS is unique in its ability to provide micron scale depth analysis in nanometric resolution.
Rutherford Backscattering Spectrometry (RBS), Elastic Recoil Detection Analysis (ERDA), Nuclear Reaction Analysis (NRA), and Particle Induced X-ray Emission (PIXE) are routinely performed. The NEC accelerator produces beams of protons or alpha particles at energies up to 3.4 MeV for protons or 5 MeV for alpha particles at currents up to 100 nA. These methods have certain advantages over conventional spectroscopies and offer unique capabilities as near-surface compositional probes. Such techniques are, in general, non-destructive and capable of yielding absolute concentrations, frequently at the sub-monolayer level. RBS provides detailed composition and thickness information from the top few micrometers of a sample, and is especially sensitive for heavy films on light substrates. PIXE provides both major element and trace element chemical analysis non-destructively and is also sensitive to heavy elements in a light matrix; minimum detectability is 100 ppm concentrations in most cases. ERDA yields separate quantitative concentration depth profiles for each element present in the sample surface. The detection system has to be able to discriminate between the different target atoms. ERS provides a unique method for measuring the H and D content in thin films with detection limit ≥ 0.01 at.%. Because of the relatively small energy loss of H in solid, the depth resolution of this method is typically ~300-600Å. NRA is used to detect and measure light elements such as boron or fluorine, or for isotopically labeled samples, such as oxides enriched in 18O.
- Sample Requirements:
- Sample size from 10mm x 10mm up to 25mm x 75mm
- Power samples can be analyzed
- Both conducting and isolating samples can be analyzed
- Nondestructive and multielemental analysis technique
- Elemental composition (stoichiometry) without a standard (1 - 5% accuracy).
- Elemental depth profiles with a depth resolution of 2 - 10 nanometers and a maximum depth of 2 - 20 microns.
- Surface impurities and impurity distribution in depth (sensitivity up to sub-ppm range).
- Elemental areal density and thus thickness (or density) of thin films if the film density (or thickness) is known.
- Diffusion depth profiles between interfaces up to a few microns below the surface.
Channeling-RBS is used to determine lattice location of impurities and defect distribution depth profile in single crystalline samples