Temperature dependent Cs retention, distribution, and ion yield changes during Cs+ bombardment SIMS

Combining Cs+ bombardment with positive secondary molecular ion detection (MCs+) can extend the analysis capability of secondary ion mass spectrometry (SIMS) from the dilute limit (<1 at. %) to matrix elements. The MCs+ technique has had great success in quantifying the sample composition of III–V semiconductors. However, the MCs+ has been less effective at reducing the matrix effect for group IV materials, particularly Si-containing compounds. The lack of success in quantifying group IV materials is primarily attributable to the high Cs surface concentrations overloading the sample surface and lowering ion yields. The Cs overload issue is caused by the mobility and relocation of the implanted Cs to the surface during an analysis. Critical to understanding the material-dependent success of the MCs+ technique and elucidating the Cs mobility is understanding how Cs is incorporated and distributed into the sample and how the Cs surface concentration affects the ionization processes. The authors provide both ...