A Study of Surface diffusion of Hydrogen by Hydrogen Microscope

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It is important to know behaviors and effect of surface reaction of hydrogen on solid surfaces. The hydrogen diffusion in solid has been studied by many investigators using classical methods for various materials. However, there are few publications on surface diffusion on solid surface because no commercially available tool for surface hydrogen analysis. Therefore, there are still unsettled problems on surface hydrogen behaviors. Now we use the time-of-flight type electron stimulated desorption (TOF-ESD) spectroscopy and a focused electron gun to study two-dimensional hydrogen distribution. A scanning type ESD ion microscope (SESDIM) measures not only hydrogen distribution but chemical analysis of hydrogen and oxygen on solid surfaces in spatial resolution of 1000 nm. It was expected to study surface diffusion of hydrogen in a region of the spatial resolution. It is necessary to cool the sample manipulator to study hydrogen diffusion because hydrogen moves on solid surface at around room temperatures. As a high precision manipulator which works at low temperatures is not available easy, it took a long time to design and product it. Difference of diffusion has been observed in the case of an aluminum covered silicon surface between-60℃ to 100℃. However, it was not enough to obtain the experimental results In contrast, this SESDIM is suitable to study oxygen diffusion on solid surface at higher temperatures. In this study, hydrogen and oxygen behaviors on a hybrid surfaces of porous silicon and silicon nitride.In addition, in the process on improvement of the SESDIM, a new X-Ray microscope which has a high spatial resolution of 100 nm in spite of low energy electron excitation (〜1 keV). In futeur if an X-Ray energy analyzer near 1 keV is developed, this X-Ray microscope is highly valuable for living body samples.