Morphological Development from Uniform Microporous Structure to Macropore-like Structure

摘要

Porous silicon is formed by electrochemical anodization in HF solution. Morphological development from a microporous structure with framework (skeleton structure) to a macroporous structure was studied. A skeleton structure can be obtained when some types of organic solvents are used. The skeleton structure changes to a macroporous structure when concentration of HF in solution decreases. Macropore formation is also observed at high current density in high-concentration HF solution. Two possible paths are proposed for each development. The skeleton structure seems to be an important key to discuss macropore formation.