Investigation of the factors determining the SIMS depth resolution in silicon-isotope multiple layers

In order to identify their controlling factors, the depth resolution parameters for secondary ion mass spectrometry, which include the decay length and the standard deviation of the Gaussian function (also referred to as the depth resolution function), for silicon atoms in a silicon matrix with silicon-isotope multiple layers were investigated under oxygen (O2+) and cesium (Cs+) ion bombardments with a wide ion energy range (from 200 eV to 10 keV) and with several incident angles. The use of silicon-isotope multiple layers in this investigation eliminated the chemical segregation effect caused by the sample composition. Measures were also taken to prevent ripple formation on the sputtered sample surface. The obtained depth resolution parameters were proportional to E1/2cos θ, where E is the primary ion energy per atom and θ is the incident angle relative to the surface normal. The relationships for decay length and standard deviation were different for the Cs+ ion, the O2+ ion with full oxidization, and t...