Sputtering investigation of boron nitride with secondary ion and secondary neutral mass spectrometry

Abstract

Sputtering of boron nitride with xenon ions was investigated using secondary ion (SIMS) and secondary neutral (SNMS) mass spectrometry. The ions generated from the ion gun were incident on the target at an angle of 50° with respect to the surface normal. The energy of ions ranged from 100 eV to 3 keV. A flood electron gun was used to neutralize the positive charge buildup on the target surface. The intensities of sputtered neutral and charged particles, including single atoms, molecules, and clusters, were measured as a function of ion energy. Positive SIMS spectra were dominated by the two boron isotopes whereas BN− and B− were the two major constituents of the negative SIMS spectra. Nitrogen could be detected only in the SNMS spectra. The intensity–energy curves of the sputtered particles were similar in shape. The knees in p-SIMS and SNMS intensity–energy curves appear at around 1 keV, which is significantly higher than the 100–300 eV energy range at which knees appear in the sputtering of medium and heavy elements by ions of argon and xenon. This difference in the position of the sputter yield knee between boron nitride and heavier targets is due to the reduced ion energy differences.