Analytical and numerical depth resolution functions in sputter profiling

Quantitative reconstruction of Ta/Si multilayer depth profiles obtained by Time-of-Flight-Secondary-Ion-Mass-Spectrometry (ToF-SIMS) using Cs+ ion sputtering

“…refs. [2,5,9,12,13]). It is important to get the normalized intensity profile for Si from the concentration profile (which is obtained by the MRI model) by multiplication with the changing, depth and concentration dependent sensitivity factor (e.g.…”

“…If the original in depth distribution of composition is known, like here, these parameters can be found by optimization of profile fitting. For SIMS, in general the information depth parameter (λ) can be set to zero [12]. If preferential sputtering is ignored, the analytical solution [12] of the MRI model can be used.…”

“…For SIMS, in general the information depth parameter (λ) can be set to zero [12]. If preferential sputtering is ignored, the analytical solution [12] of the MRI model can be used. However, as already noted in ref.…”

“…The MRI model [9,12] is a convenient means to quantify measured depth profiles by reconstruction of their shape using three characteristic depth profiling parameters. If the original in depth distribution of composition is known, like here, these parameters can be found by optimization of profile fitting.…”

Depth resolution in sputter profiling revisited

“…In the MRI model, the DRF is represented by three fundamental, physically well‐defined parameters: atomic Mixing, Roughness and Information depth (with every parameter given by a quantity characteristic for the analysis method applied). Thus, the depth resolution Δ z directly depends on the respective values of the above parameters which establish the DRF (see section on Asymmetric, non‐Gaussian DRF for interfaces and delta layers). For simplicity, matrix effects and preferential sputtering are ignored in the following.…”