Kinetic and thermodynamic peculiarities of anodic oxidation of silicon carbide in ethylene glycol based electrolyte

Anodization behavior of n-type 6H-SiC in 1 M H3PO4 solution in ethylene glycol containing 1 M H2O in comparison with 0.04 N KNO3 solution have been examined. It has been shown that Gunterschulze and Betz's equation holds true for total current density in the range 3-20 mA/cm2 under galvanostatic regime of anodic oxidation of silicon carbide. Based on thermodynamic consideration it is proposed that enhanced growth rate in presence of phosphoric acid in electrolyte can be attributed to formation of additional amount of SiO2 coupled with P2O5 or P by reactions between SiC and phosphate-anions.