Shave-off depth profiling: Depth profiling with an absolute depth scale

We have proposed to use oxygen cluster ions, which are much larger than molecular ions, as primary ions for secondary ion mass spectrometry (SIMS). A high intensity gas cluster ion source with a current density of a few mAs/cm2 has been developed. Secondary ions emitted from Si have been investigated under O2 and Ar cluster ion bombardment. A large enhancement of the yield of secondary ions produced by large O2 and Ar cluster ions was found. The SIMS system utilizing large O2 cluster ions must give both excellent depth resolution and high secondary ion yield.