Self-Ordered Nanocolumnar Pore Formation in the Photoelectrochemical Etching of 6H SiC

A columnar mesoporous structure was obtained in single-crystalline n-type 6 H SiC by photoelectrochemical etching. The 20 nm diameter cylindrical pores were about 200 μ m long, parallel, and distributed in a self-ordered manner. The pore morphologies and etching curves under different experimental conditions for both Si and C-face SiC samples are discussed. It is found that constant voltage etching on C-face SiC is crucial for the columnar pore formation.