Ga-focused ion beam time-of-flight secondary ion mass spectrometer analysis of the grain boundary segregation/precipitation of boron in steel

Ga-focused ion beam time-of-flight secondary ion mass spectrometry (FIB-TOF-SIMS) analysis was performed to investigate the grain boundary segregation/precipitation of boron in steel. To overcome the low secondary ion yield from the primary Ga⁺ source and the sensitivity using a high-resolution Ga-FIB source, a low energy oxygen ion beam was used prior to the Ga-FIB-TOF-SIMS analysis. As a result, it was found that Ga-FIB-TOF-SIMS is a very powerful tool for mapping boron segregation and/or precipitation in steel with a spatial resolution of ~200 nm. In addition, the results were strongly dependent on the surface composition.