Room light anodic etching of highly doped n-type 4 H-SiC in high-concentration HF electrolytes: Difference between C and Si crystalline faces

• Published in: Nanoscale research letters Vol. 7; no. 1; p. 367
• Main Authors: Gautier, Gael, Cayrel, Frederic, Capelle, Marie, Billoué, Jérome, Song, Xi, Michaud, Jean-Francois
• Format: Journal Article
• Language: English
• Published: New York Springer New York 03-07-2012; BioMed Central Ltd; SpringerOpen; Springer
• Subjects: Chemistry and Materials Science; Engineering Sciences; Materials Science; Micro and nanotechnologies; Microelectronics; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Porous Semiconductors - Science and Technology 2012; Si face; C face; Porous silicon carbide; Electrochemical etching
• ISSN: 1556-276X; 1931-7573; 1556-276X
• DOI: 10.1186/1556-276X-7-367

In this paper, we study the electrochemical anodization of n-type heavily doped 4 H-SiC wafers in a HF-based electrolyte without any UV light assistance. We present, in particular, the differences observed between the etching of Si and C faces. In the case of the Si face, the resulting material is mesoporous (diameters in the range of 5 to 50 nm) with an increase of the ‘chevron shaped’ pore density with depth. In the case of the C face, a columnar morphology is observed, and the etch rate is twice greater than for the one for the Si face. We've also observed the evolution of the potential for a fixed applied current density. Finally, some wafer defects induced by polishing are clearly revealed at the sample surfaces even for very short etching times.