| AVS 56th International Symposium & Exhibition | |
| Applied Surface Science | Thursday Sessions |
| Session AS-ThA |
| Session: | Chemical State Depth Profiling |
| Presenter: | J. Matsuo, Kyoto University, Japan |
| Authors: | J. Matsuo, Kyoto University, Japan S. Ninomiya, Kyoto University, Japan K. Ichiki, Kyoto University, Japan H. Yamada, Kyoto University, Japan M. Hada, Kyoto University, Japan T. Aoki, Kyoto University, Japan T. Seki, Kyoto University, Japan |
| Correspondent: | Click to Email |
Soft materials, such as organic or biological materials are of interest since last decade, because of their structural, functional and environmental flexibility. However, very few techniques are available for soft material analysis, because energetic probes destroy structure and change chemical states of soft materials during the analysis. SIMS analysis and molecular depth profiling of soft materials with polyatomic and cluster ions have been demonstrated recently. The multiple collisions and high-density energy deposition of these ions on solid surfaces induce enhancement of sputtering and secondary ion yields, as well reduced residual surface damage compared with other techniques.
We have demonstrated that molecular depth profiling with large Ar cluster ions is possible for poly-carbonate (PC) and poly-styrene (PS), which is difficult to analyze with C60 ion beam. These results indicate that extreme low energy beam is necessary for molecular depth profiling. In case of large Ar cluster beam, the kinetic energy of a few eV/atom, which is comparable to the bonding energy of molecules, is realized. In addition to this, no Ar remains on the surface, because of its low binding energy. Therefore, Large Ar cluster ion beam irradiation rarely leads to damage accumulation on the surface of the polymers, and these characteristics as etching beam are also suitable for other depth profiling techniques. The surface chemical states of the polymers were measured with X-ray photoelectron spectrometry (XPS) before and after etching. The chemical states of the poly m ethyl methacry late (PMMA) sample etched with Ar atomic ion beams differed significantly from those of the unirradiated sample, whereas the chemical states were maintained even after etching with large Ar cluster ion beams. According to the detail analysis of C1s and O1s spectra, atomic composition and chemical state are very close to the ideal values.
Atomistic mechanism of energetic cluster impacts and prospect for this technique will be discussed in conjunction with possible applications.