COMPARATIVE-STUDIES OF SIMS AND SNMS ANALYSES DURING THE BUILD UP OF SPUTTER EQUILIBRIUM UNDER OXYGEN AND RARE-GAS ION-BOMBARDMENT

Sputtering of solid surfaces by using a focused ion beam is the basis for secondary ion mass spectrometry (SIMS) and sputtered neutral mass spectrometry (SNMS). The ion bombardment initiates not only redistribu tion of sample atoms but also massive changes in the surface and near surface composition of the bombarded area due to the sputter process a nd implantation of the primary ions. Changes in the matrix-composition affects the secondary ion yields and therefore a steady state (sputte r equilibrium) has to be reached before SIMS data can give quantifiabl e results. SNMS is much less affected by those yield effects and there fore a combination of SIMS and SNMS can establish a basis for interpre tation of SIMS data before the steady state is reached, In order to de termine the effects of primary ion incorporation, we applied different primary ion species successively to generate different equilibria. An oxygen ion beam oxidizes the sample surface and by using a rare gas p rimary ion (PI) this oxide can be removed and analyzed.