Monitoring of Anodization Process

Confronting the recorded U(t) curves and SEM images of the porous structure formed, the following can be concluded formation of uniform nanoporous structure corresponds to a steep increase of U(t) during 

Yet another characteristic feature of the PSC fabricated at high anodization currents was the existence of a disordered phase at the 

Considering the influence of applied conditions on stoichiometry deviation in SiC under electrochemical treatment, let us also present some data related to silicon carbide anodization in the potentiostatic regime. The treatment was performed using HF-based electrolyte under conditions where anodic current density values are 4-10 mA cm-2. In spite of the value of the current being comparable with that used for the formation of nanoporous PSC structures, SiC anodization under potentiostatic conditions results in built-in adherent film ( anodic film in the 

An elemental analysis of the anodic films performed both with AES and SEM energy-dispersive X-ray spectrometry (EDXS) showed that the films had 11 at. % average deviation from the starting material stoichiometry towards carbon enrichment, and contained 6 at.% of oxygen and 9 at.% of fluorine. Also, current-voltage (I-V) measurements of the speci-men/electrolyte junction (performed under illumination) before and after the treatment revealed enhancement of photoresponse from the SiC surface covered with the anodic film as compared with the starting material. 

By analogy with photosensitive anodic films appearing over the surface of silicon during its treatment in fluorine-containing electrolytes, it can be suggested that the built-in film represents a mixed phase of electrochemical reaction products or results from the anodized surface amorphization [27,28]. In its turn, this indicates that under potentiostatic conditions the chemical processes at the SiC/HF junction are predominant. The results obtained emphasize that not every porous-like phase formed as a result of SiC anodization can be considered as PSC. 

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