Effects of Ion Optics on the Sensitivity Factors in Secondary Neutral Mass Spectrometry Measurements

Abstract

The effects of the ion optics of the SNMS (secondary neutral mass spectrometry) INA-3 system on the intensity ratios, from which the relative sensitivity factors can be calculated, have been investigated for several III-V semiconductors: GaAs, GaP, and InP. It was found that the intensity ratios change significantly, depending on the electrode potentials of the ion optics and on the mass difference (AM) between the major constituent elements: within 90% regions of optimum electrode voltages and between OM=6 and 84 amu, the maximum total relative deviation of relative intensities increases from about 10% to 250%.

Instrumental Effects on Sensitivity Factors in Secondary Neutral Mass Spectrometry Measurements

“…The effects of ion optics of INA-3 have been investigated and are described in ref. 12. Briefly, intensity ratios change very much by ion optics setting condition, depending on mass difference between the constituents; in the case of GaAs the variation of intensity ratios was less than 20%, while for InP it was more than 200%.…”