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Adsorption of transition metal ions such as Fe(III), Ni(II), and Zn(II) on silicon wafers in ammoniac hydrogen peroxide solution (SC-1 solution) has been studied. It was found by comparing the experimental results with the equilibrium calculations that the main adsorption species is the dissolved neutral hydroxide complex. This was supported by the calculated free energy change of adsorption of hydroxide complexes.

Total reflection X-ray fluorescence spectrometry (TXRF) is widely used for the determination of surface metal contamination on a silicon wafer. In TXRF measurements, calibration standard samples are needed to quantify the metal concentration.We propose a new method for the preparation of calibration standard samples for TXRF. The method is called "Immersion in Alkaline Hydrogen Peroxide Solution (IAP)", in which the silicon wafers are immersed in an intentionally contaminated alkaline hydrogen peroxide solution. Samples made by the IAP method are suitable calibration standard samples for TXRF because of their good depth profile reproducibility and good uniformity on the surface as well as homogeneity in a given batch. They can also be applied for making a cross-check among plural TXRF instruments as well as among different analytical methods. KeywordsTotal reflection X-ray fluorescence spectrometry (TXRF), standard sample, silicon wafer, transition metal contamination,

Thermal expansions (TEs) of dense and porous samples were studied for mixed conductor Sr(Co 0.9 Nb 0.1 )O 3Àd (SCNb). In Ar, the TEs of the porous samples were almost the same as those of a dense sample, which had the character of conventional TEs. In air, on the other hand, the TEs of porous samples were larger than the dense sample. The difference of TE in air resulted from a change in the chemical expansion, which originated from the variation of oxygen vacancy concentration. On decreasing the density, oxygen incorporation from air into SCNb took place at a lower temperature, and the length change upon chemical expansion was increased.