Angle-resolved ESCA methods: Distribution and molecular conformation of perfluoropolyether lubricant

Simple but useful methods for interpreting angle-resolved ESCA data from re al-world samples are presented. First is a two-tiered overlayer model allow ing thinly covered and thickly covered substrate. It can be productively ap plied, even in a manual fashion, with common office spreadsheets. Next is a triangle-wave roughness model that can reasonably approximate substrate po lishing texture. Finally, a two-slab overlayer model is presented. With the help of canned minimization routines, it can bring out conformation subtle ties in overlayer structures and even isolate a deeply buried monatomic lay er. The following art: presented as examples Perfluoropolyether (Zdol) lubr icant on hard disk carbon overcoat shows coexisting monolayer and multilaye r regions consistent with structures identified by surface energy and ellip sometric surface diffusion measurements. Polishing texture of disks is dete cted but leads to little change in the two-tiered model results. Layering w ithin the lubricant shows significant perfluoropolyether backbone adjacent to the overcoat surface accompanied by a discernible excess of ether oxygen . The latter indicates that the inverted-U conformation sometimes sketched for bonded lubricants is an exaggeration, certainly for the system studied. (C) 2000 American Vacuum Society. [S0734-2101(00)14604-4].