XRF and SIMS/SNMS analyses of BaxSr1-xTiO3 dielectrics

The development of analytical tools and procedures for process control is a prerequisite for the integration of high permittivity and/or ferroelectric materials in CMOS devices. The thickness and composition of perovskite oxide films were determined by wavelength dispersive X-ray fluorescence analysis (XRF) with special emphasis on the ratio of the group-II elements to the Ti content, and a precision of 0.5% was achieved for a typical film thickness of 20-30 run. Secondary ion mass spectrometry (SIMS) and sputtered neutrals mass spectrometry (SNMS) was used for depth profiling to determine film homogeneity and elemental interdiffusion at heterointerfaces. Examples are given for BaxSr1-xTiO3 and SrTiOx, thin films which were grown in a prototype MOCVD production tool. No interdiffusion was observed for films grown at 600 degreesC on Pt electrodes in contrast to films grown directly on Si.