Self-organization of pores in SiC/Si composite structures

• Published in: Journal of applied physics 1998-05, Vol.83 (9), p.4647-4651
• Main Author: Parkhutik, Vitali P.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.367250

Anodic dissolution of a structure composed of the chemically vapor deposited amorphous SiC film and silicon wafer results in the formation of a system of hexagonally ordered pore colonies. This intriguing effect takes place when the structure SiC/Si is subjected to a short-time (several seconds) anodization in 48% HF/ethylene glycol solution. As a result of this procedure the SiC layer is converted into a porous one with diameters of the pores not exceeding 30–50 nm. Continuing the anodization process beyond the complete conversion of SiC layer into a porous one results in porous structure formation in an underlying Si wafer. It appears that pores in silicon form colonies arranged in hexagonal order. Characteristic distance between neighboring colonies increases with the anodic current density applied during the electrochemical process. It is assumed that the effect of self-ordered pore colonies growth is due to the accumulation of mechanical stress at SiC/Si interface due to a lattice mismatch and dynamic pressure developed in the pores during the anodic dissolution reaction.