Papers - SAITO, Nagahiro

Effect of citric acid and EDTA addition on Cu-In alloy electrochemical deposition Open Access

Ishizaki T., Saito N., Fuwa A.

Materials Transactions, JIM   Vol. 40 ( 9 ) page： 867 - 870   1999

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Materials Transactions, JIM  

The standard electrode potential for Cu is 0.34 V and that of In is -0.34 V, which means that their deposition potentials are far apart, making the co-deposition difficult from a simple solution containing Cu and In ions. In order to bring these deposition potentials closer, a complex forming reagent of citric or EDTA is added to the CuSO4-In2(SO4)3 solution. The effect of these reagents was examined by linear sweep voltammetric measurement. An electrochemical deposition experiment of Cu-In alloy was conducted where effect citric acid or EDTA addition, current density and Cu concentration were examined.

DOI： 10.2320/matertrans1989.40.867

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Theoretical analysis for thermal chemical vapor deposition from Tetraethoxysilane using a semi-empirical molecular orbital method Open Access

Hirota M., Saito N., Ishizaki T., Fuwa A.

Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals   Vol. 63 ( 7 ) page： 931 - 937   1999

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals  

In order to elucidate the reaction mechanism for the Tetraethoxysilane (TEOS) thermal decomposition at atmospheric pressure, its pertinent elemental reactions involving the SiO(OC2H5)2 reaction intermediate were first proposed. For respective species formed in these elemental reactions, the total energy and the electronic state were calculated using a semi-empirical molecular method. The adsorption process which involves adsorbent species formation and surface reaction mechanism were then analyzed from the standpoint of molecular orbital formation and charge transfer mechanism, and the results are summarized as follows: (1) A reaction intermediate, SiO(OC2H5)2(1A1), is probably formed through the following β-elimination reaction route: Si(OC2H5)4(1A1)→SiO(OC2H5) 2(1A1)+C2H4(1A1)+C2H5OH (1A1). (2) The adsorption of SiO(OC2H5)2(1A1) on SiO2 occurs with charge transfer from the dangling bond of silicon atom at an active site of the SiO2 surface to the π*-LUMO unoccupied orbital of SiO(OC2H5)2(1A1). (3) The sequence of surface reactions is considered as follows: (1) First, a dissociation reaction of C2H5(2A′) takes place, whereby producing a double bond between silicon atom and oxygen atom of the intermediate, since they possess unpaired electrons. (2) Si-O bond is successively formed following the mechanism similar to the one operating in the adsorption of SiO(OC2H5)2(1A1) on SiO2. (3) Electronic state of the reactant finally formed is in the 1A1 state, which has a σ-orbital to be fully occupied with electrons.

DOI： 10.2320/jinstmet1952.63.7_931

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Texture of thin silicon films deposited from Si<inf>2</inf>Cl<inf>6</inf> Open Access

Kato Y., Saito N., Fuwa A.

Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals   Vol. 60 ( 8 ) page： 744 - 750   1996.8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals  

Thin Silicon films were deposited on non-crystal quartz glass substrates by hydrogen reduction of Si2Cl6 at temperatures from 650 to 900 °C in a horizontal hot wall reactor. The microstructures of the thin silicon films deposited under various experimental conditions were analyzed. The thin silicon films deposited from 750 to 850 °C have the highest degree of preferred (220) plane orientation with the 〈111〉 direction along the plane, and the cross-sectional morphology exhibits a columnar structure. The experimental values of the lattice spacing approach a value cited in JCPDS for the films deposited in a higher temperature range. In the lower temperature range the morphology of surface is flat and smooth, and in the higher temperature range the surface becomes uneven remarkably.

DOI： 10.2320/jinstmet1952.60.8_744

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