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Are cluster ion analysis beams good choices for hydrogen depth profiling using time‐of‐flight secondary ion mass spectrometry?
Author(s) -
Zhu Zihua,
Shutthanandan Vaithiyalingam
Publication year - 2012
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3776
Subject(s) - ion , chemistry , mass spectrometry , cluster (spacecraft) , secondary ion mass spectrometry , deuterium , hydrogen , profiling (computer programming) , time of flight , analytical chemistry (journal) , ion beam , atomic physics , nuclide , nuclear physics , physics , organic chemistry , chromatography , computer science , programming language , operating system
For more than three decades, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) has been used for elemental depth profiling. In recent years, cluster primary ion sources (principally, C 60 + , Bi n + , and Au n + ) have become widely available, and they can greatly enhance the signal intensity of molecular ions (10–1000 times). Understanding the performance of cluster ion analysis beams used in elemental depth profiling can greatly assist normal ToF‐SIMS users in choosing the optimal analysis beam for depth profiling work. Presently, however, the experimental data are lacking, and such choices are difficult to make. In this paper, hydrogen and deuterium depth profiling were studied using six different analysis beams—25 keV Bi + , Bi 3 + , Bi 5 + , 50 keV Bi 3 2+ , 10 keV C 60 + , and 20 keV C 60 2+ . The effort shows that cluster primary ions do enhance H − and D − yields, but the enhancement is only about 1.5–4.0 times when compared to atomic Bi + ions. Because the currents of atomic ion analysis beams are much stronger than the currents of cluster ion analysis beams for most commercial ToF‐SIMS instruments, the atomic ion analysis beams can provide the strongest H − and D − signal intensities, and may be the best choices for hydrogen and deuterium depth profiling. In addition, two representative nuclides, 30 Si and 18 O, were also studied and yielded results similar to those of H − and D − . Copyright © 2011 John Wiley & Sons, Ltd.