Adsorbed species and its diffusion behaviors in GeO2/Ge stacks, which are future alternative metal-oxide-semiconductor (MOS) materials, have been investigated using various physical analyses. We clarified that GeO2 rapidly absorbs moisture in air just after its exposure. After the absorbed moisture in GeO2 reaches a certain limit, the GeO2 starts to absorb some organic molecules, which is accompanied by a structural change in GeO2 to form a partial carbonate or hydroxide. We also found that the hydrogen distribution in GeO2 shows intrinsic characteristics, indicative of different diffusion behaviors at the surface and at the GeO2/Ge interface. Because the impurity absorbability of GeO2 has a great influence on the electrical properties in Ge-MOS devices, these results provide valuable information in realizing high quality GeO2/Ge stacks for the actual use of Ge-MOS technologies.

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After ion implantation, annealing is needed to activate dopant and recover crystalline. However, in some annealing conditions there is a possibility that activation annealing forms defects in the implanted region, which may cause errors in SIMS depth profiles. The purpose of this study is to make clear the influence of defects generated during annealing on the conventional front-side SIMS (FSS) depth profiles, and to provide proper measurement condition to get accurate depth profiles using back-side SIMS (BSS) technique as another beneficial application. In this study, BF 2 were implanted into crystalline silicon, and three different samples were treated, respectively, as implanted, 750 and 900• annealing. In an as-implanted sample, BSS depth profiles of boron confirmed those obtained by FSS. On the other hand, in annealed samples, BSS depth profiles were steeper than those of FSS. This result suggests that the degradation of depth resolution in FSS cannot be explained only by the effect of ion mixing due to primary ions, but may be related with the crystalline structure in the implanted region. Therefore, BSS techniques can also be indispensable for getting more precise depth profiles in the implanted region of silicon.

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