Depth resolution enhancement by combined DSIMS and TOF-LEIS profiling

A combination of dynamic secondary ion mass spectroscopy (DSIMS) and time-of-flight low-energy ion scattering (TOF-LEIS) has been applied to acquire a composition depth profile of MoSi multilayers. During the sequential Ar⁺ sputtering secondary ions were monitored while in-between the sputtering cycles the TOF-LEIS spectra of scattered He neutrals were acquired. All the measured TOF-LEIS spectra versus sputtering time were displayed in one bitmap from which the depth profiles for different scattering depths were derived and analyzed. Analyzing the TOF-LEIS spectra of He particles scattered from the areas below the layer altered by ion-beam mixing led to an improvement of the depth resolution. In this way the resolution limits due to mixing phenomena can be overcome. Finally, the direct comparison of the DSIMS and TOF-LEIS depth profiles was carried out.