Determination of the angle of incidence in a Cameca IMS‐4f SIMS instrument

Abstract

AbstractAn improved model for the calculation of the angle of incidence of primary ions is presented for describing secondary ion mass spectrometry (SIMS) measurements in the low primary energy region (<7.5 keV) of a Cameca IMS‐4f with positive primary ions and a positive secondary detection mode. The model explains some of the inconsistencies observed between experiment and the approximative model used so far. Our improvement takes into account the effect of the deflection plates for beam positioning, which leads to a change in the angle of the primary ion with respect to the optical axis of the primary column. A comparison with experimental results is accomplished, showing the improvement of the new model. This new model also explains the slope of the crater bottom in the x‐direction at low primary ion energies, owing to a different sputter yield from one side to the other of the crater bottom.