INTERLABORATORY COMPARISON OF THE DEPTH RESOLUTION IN SPUTTER DEPTH PROFILING OF NI CR MULTILAYERS WITH AND WITHOUT SAMPLE ROTATION USING AES, XPS AND SIMS/

In order to provide a consistent judgment on the capabilities and limi tations of the sample rotation approach to depth profiling, a round ro bin (interlaboratory comparison) was organized between four laboratori es on identical samples using AES, XPS and SIMS. The sample consisted of an Ni/Cr multilayer with a total of 16 alternating Ni and Cr layers with a single layer thickness of 30 nm. Sputter profiling was perform ed with a rastered beam of 3 keV Ar+ ions at an incidence angle of 45- degrees to the surface normal, with and without sample rotation. Test runs were additionally performed with BCR standard samples of 30 nm th ick Ta2O5 layers on Ta. For sample rotation, depth profiles of the Ni/ Cr multilayer by AES and SIMS show a marked improvement in depth resol ution of about a factor of two for lower sputter depth (30 nm) and fou r to five for greater sputter depth (450 nm). The depth resolution det eriorates with depth for stationary samples, but is found to be indepe ndent of depth when using sample rotation. For XFS, the depth resoluti on improvement for sample rotation is less pronounced. Agreement betwe en the different laboratories and techniques is excellent and clearly demonstrates the capabilities of sample rotation in depth profiling st udies.