Parasitic ion-implantation produced by a Kaufman-type ion source used for planar etching of surfaces

Total reflection X-ray fluorescence spectrometry (TXRF) and photoelectron spectroscopy (XPS) were used to characterize ion-etched surfaces of Si wafers, a quartz glass and vacuum-metallized multilayer on a Si wafer. These samples were first treated with low kinetic energy ions of a broad beam Kaufman-type ion source. By repeating this method of sputtering, layers can be removed stepwise and in combination with surface analysis by TXRF a multielement depth profiling can be carried out. The depth resolution is of the order of 3 nm. Unfortunately, ion-etching leads to uncontrollable ion implantation and thus to a contamination of the samples with some 'parasitic' elements which may disturb the multielement characterization of the original surfaces. XPS with Ar sputtering was used to confirm the implantation of interfering elements in the freshly ion-etched samples.