PHOTOASSISTED ANODIC ETCHING OF GALLIUM NITRIDE

The first study of photo-assisted anodic etching of unintentionally do ped n-GaN at room temperature is reported here. The electrolyte used i s a mixture of buffered aqueous solution of tartaric acid and ethylene glycol. The etching rate varies from similar to 20 Angstrom/min to as high as 1600 Angstrom/min. A systematic study shows that (i) the etch rate, as well as the surface roughness, increases with the current de nsity, (ii) the etching rate is the highest when the pH of the electro lyte is similar to 7; and (iii) the etching is faster when there is mo re ethylene glycol in the electrolyte solution.