In this paper a nonthermal photoelectrochemical etching technique for [~-SiC is reported. The measured etch rates of 1-100 ~m/min in this process are much faster than other etching methods currently available for this material. UV radiation is necessary for efficient photogeneration of holes near the surface. These holes are transported in the presence of an external bias to the semiconductor/liquid interface, where dissolution occurs through the anodic oxidation of the SiC and the removal of the oxide by F-ions present in the electrolyte. The electrochemistry of B-SiC and the etching process variables are discussed.

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Stress corrosion cracking of in acidic methanol at anodic potential has been studied. The specimen surface morphology was examined as a function of strain rate, electrode potential, water content, and heat treatment. Depending on the test conditions, two kinds of cracks can be formed: those along the slip traces and those perpendicular to the applied stress. A new model is proposed to explain the initiation of these cracks. The cracks along the slip traces result from preferential dissolution of moving dislocations along the slip planes. Rupture of the material between these cracks results in the perpendicular cracks.