BEYOND THE SURFACE WITH SIMS

摘要

It is expensive to buy and, at times, difficult to run, but secondary ion MS (SIMS) has earned a place as an essential surface analysis technique. "SIMS is, above all, a method for analysis of trace elements, detecting all the elements to some degree," says SIMS researcher Peter Todd (Oak Ridge National Laboratory). "It is an in situ measurement that looks at both light and heavy species," says Andrew Davis, regional sales manager for Cameca Instruments. Although the inorganic applications of SIMS have become almost routine, the technique is now carving a niche for organic surface analysis. SIMS also offers extremely good spatial resolution—on the order of 1000 A or less. Detection limits for elemental analysis range from part-per-million to part-per- billion levels. "SIMS also has a unique capability for measuring an analyte as a function of depth," says Todd. By destruc-tively eroding away the surface, analysts can routinely probe down to micrometer s depths with depth resolutions better than 100 A.