Oxygen ion beam-induced abnormal surface topographic development at Ta/Si interface

We report on an abnormal surface topographic development at a Ta/Si interface, which is believed to be one of the major sources of the irregular interface artifacts in secondary ion mass spectrometry depth profiling by oxygen ion beam. Round crater type topographic development was observed at the interface by sputtering with a 7 keV O⁺₂ ion beam and was found to have been formed by blister formation and gradual opening of its center. We suggest that the driving force for this abnormal topographic development is a buildup of compressive stress caused by a volume increase of the Ta layer near the interface, due to oxidation.