| AVS 59th Annual International Symposium and Exhibition | |
| Applied Surface Science | Thursday Sessions |
| Session AS-ThM |
| Session: | Applications of Large Cluster Ion Beams |
| Presenter: | N. Havercroft, ION-TOF USA, Inc. |
| Authors: | N. Havercroft, ION-TOF USA, Inc. D. Rading, ION-TOF GmbH, Germany S. Kayser, ION-TOF GmbH, Germany R. Moellers, ION-TOF GmbH, Germany F. Kollmer, ION-TOF GmbH, Germany E. Niehuis, ION-TOF GmbH, Germany |
| Correspondent: | Click to Email |
In the last few years it has been demonstrated that massive argon cluster ions can successfully be applied as primary ion projectiles in SIMS [1-7]. They can not only be applied to sputter organic surfaces without damaging the molecular information, it also has been shown that they desorb larger molecular ions effectively [4] with little fragmentation [2][7]. Although the secondary ion yield decreases with increasing cluster size [4][6], the ability of these projectiles to produce cleaner spectra emphasizing molecular ion signals makes them interesting for analysis purposes as well [5-7]. However, the generation of short primary ion pulses has been difficult due to the large cluster size distribution which typically ranges from hundred to several thousand atoms/cluster. The resulting flight time dispersion of the different cluster sizes determines the primary ion pulse lengths and thus limits the mass resolution.
We equipped a standard TOF.SIMS 5 instrument with a newly developed Ar cluster ion source. The 90° pulsing system of this primary ion gun enables the generation of long as well as short primary ion pulses. The long pulses are suited for sputtering purposes in a dual beam experiment whereas the short pulses are used for high mass resolution TOF-SIMS spectrometry. The pulsing system also allows the selection of a specific cluster size range out of the large distribution with a mass resolution of about 2 for long and 80 for short pulses.
In this study we will apply large Ar clusters ranging from several hundred to several thousand atoms/cluster at different beam energies to a variety of molecular surfaces. We will present and compare data about the influence of the cluster size and beam energy on the sputtering as well as analysis capabilities emphasizing on the spectra appearance and the fragmentation behavior.
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[3] S. Ninomiya, K. Ichiki, H. Yamada, Y. Nakata, T. Seki,T. Aoki, J. Matsuo,
Rapid Communications in Mass Spectrometry, 23, (2009), 1601-1606
[4] K. Mochiji, M. Hahinokuchi, K. Moritani, and N.Toyoda, Rapid Commun. Mass Spectrom.23 (2009) 648
[5] S. Ninomiya, Y. Nakata, Y. Honda, K. Ichiki, T. Seki, T. Aoki, J. Matsuo, App. Surf. Sci., 255 (2008), 1588-1590
[6] S. Rabbani, A.M. Barber, J.S. Fletcher, N.P. Lockyer, J.C. Vickerman, Anal. Chem., 83, (2011), 3793-3800
[7] S. Kayser, R. Moellers, D. Rading, F. Kollmer, E. Niehuis,
to b e published in Surf. Interface Anal. SIMS XVIII Proceedings