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SIMNRA

Computer simulation of RBS, ERDA, NRA and MEIS

by Matej Mayer

Max-Planck-Institut für Plasmaphysik

SIMNRA

Computer simulation of RBS, ERDA, NRA and MEIS

by Matej Mayer

EXAMPLES

Some examples for the abilities of SIMNRA:

Backscattering with Non-Rutherford cross sections

2000 keV protons backscattered from carbon. Experimental data and SIMNRA simulation.
2000 keV protons backscattered from carbon, scattering angle 165°. Dots: Experimental data; Solid line: SIMNRA simulation.
2000 keV protons backscattered from silicon. Experimental data and SIMNRA simulation.
2000 keV protons backscattered from silicon, scattering angle 165°. Dots: Experimental data; Solid line: SIMNRA simulation.

ERDA with Non-Rutherford cross sections

Elastic recoil detection analysis (ERDA) with 2600 keV 4helium incident ions for detection of hydrogen and deuterium. Experimental data and SIMNRA simulation.
ERDA with 2600 keV 4He incident ions and dE-E telescope for detection of H and D at a recoil angle of 30°. Both cross-sections are non-Rutherford. Dots: Experimental data; Lines: SIMNRA simulation.

Multiple and plural scattering

500 keV 4helium backscattered from 100 nm gold on silicon. 
                     Experimental data and SIMNRA simulations with the single scattering approximation and with dual scattering as apprroximation of plural large-angle scattering.
500 keV 4He backscattered from 100 nm Au on Si, scattering angle 165°. The background below the low energy edge of Au is due to plural large angle scattering, which is approximated in the dual scattering approximation by SIMNRA. The single scattering approximation, which is normaly used, fits the experimental data poorly. From [Eckstein99].

Surface roughness

1.5 MeV 4helium backscattered from a rough nickel film on carbon. Experimental data and SIMNRA simulations for a smooth and a rough nickel film.
1.5 MeV 4He backscattered from a rough Ni-film on carbon, scattering angle 165°. Mean Ni-film thickness 240 nm, FWHM of roughness 23 nm. Dots: Experimental data; Dashed line: SIMNRA simulation assuming a smooth Ni film; Solid line: SIMNRA simulation assuming a rough Ni film. From [Mayer02].
2.0 MeV 4helium backscattered from a rough oxidised aluminum film on carbon. Experimental data and SIMNRA simulation.
2.0 MeV 4He backscattered from a rough oxidised Al-film on carbon, scattering angle 165°. The initial film was strongly eroded by plasma exposure, and some Ni was deposited. Dots: Experimental data; Solid line: SIMNRA simulation with a mean film thickness of 184 nm and a roughness FWHM of 176 nm. Such extreme roughnesses cannot be described by smooth layers or diffusion profiles. From [Mayer02].
2.5 MeV protons backscattered from a 3.5 µm thick tungsten film on a rough carbon substrate. Experimental data and SIMNRA simulations using a smooth and a rough substrate.
2.5 MeV protons backscattered from a 3.5 µm thick tungsten film on a rough carbon substrate, scattering angle 165°. The mean roughness of the carbon substrate was 8.2 µm. Dots: Experimental data; Dashed line: SIMNRA simulation assuming a smooth substrate; Solid line: SIMNRA simulation assuming a rough substrate. From [Mayer02].

Structured layers

Focused ion beam cross-section through a silicon grating on top of a tantalum interlayer on top of silicon substrate. Schematic representation of the measurement geometry parallel to the silicon grating structure. Backscattering of 1500 keV 4He ions from a silicon grating on top of a tantalum interlayer. Measurement parallel to the grating structure. Experimental spectrum and simulation with SIMNRA 7.
Backscattering of 1500 keV 4He ions from a silicon grating on top of a tantalum interlayer on top of silicon substrate. Top: Focused ion beam cross-section through the sample structure. Middle: Schematic representation of the measurement geometry parallel to the silicon grating structure, scattering angle 165°. Bottom: Experimental spectrum (black dots) and simulation (red line) with SIMNRA 7. From [Langhuth11], [Mayer16a].

Porous layers

Scanning electron micrograph of a porous V2O5 layer. Backscattering spectra of 1500 keV 4He from a porous V2O5 layer at a scattering angle of 165°. Experimental data and computer simulations with SIMNRA 7.
Top: Scanning electron micrograph of a porous V2O5 layer. Bottom: Backscattering spectrum of the porous V2O5 layer on silicon substrate using 1500 keV 4He ions at a scattering angle of 165°. Dots: Experimental data; Solid line: Computer simulation with SIMNRA 7 assuming a porous layer with 40% pore fraction and a pore diameter of 31 nm; Dashed line: Computer simulation assuming a dense layer. From [Mayer14].

Pile-up simulation

Backscattering spectrum of 2 MeV 4helium on gold with pile-up. Experimental data and SIMNRA simulations with and without pile-up.
Backscattering spectrum of 2 MeV 4He on bulk gold with pile-up, measured with a Canberra DSP 9660, PUR on, 6% dead time. Dots: Experimental data; Dashed line: SIMNRA simulation without pile-up; Solid line: SIMNRA simulation with pile-up.