We have investigated a galvanostatic oscillation phenomenon during anodization of a silicon (Si) crystal electrode in fluoride electrolytes using infrared absorption spectroscopy in multiple internal reflection geometry (MIR-IRAS). We confirm that the electrode surface is covered with a thin oxide layer during the course of galvanostatic oscillation. We observe a weak oscillation of the oxide thickness that synchronizes with the oscillation of an anodic potential. We also find that when the anodic potential falls to its minimum, hydrogen-substituted oxide (suboxide, Si(O3)-H) forms on the electrode surface, and it diminishes before the anodic potential reaches its maximum. We propose a model of galvanostatic oscillation in which it is assumed that a decrease in the anodic potential is due to the formation of pits in the oxide over-layer and low-quality oxides containing Si(O3)-H species are preferentially formed at pit sites because of the concentration of the anodic current at those sites. We suggest that formation of an inhomogeneous oxide layer plays a crucial role for the galvanostatic oscillation phenomenon.
|ジャーナル||Physica Status Solidi (A) Applied Research|
|出版ステータス||Published - 2003 5 1|
|イベント||Proceedings of The 3rd International Conference Porous Semiconductors - Sience and Technology - Puerto de la Cruz, Spain|
継続期間: 2002 3 10 → 2002 3 15
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