Dry etch damage in n-type GaN and its recovery by treatment with an N2 plasma

We report on etch-induced damage in n-type GaN caused by an inductively coupled plasma, and damage recovery by means of treatment with an ${\mathrm{N}}_{\mathrm{2}}$ plasma. As the plasma dc bias was increased by increasing the rf table power during etching, the optical and electrical properties of the etched GaN films deteriorated as the result of etch-induced damage. However, an ${\mathrm{N}}_{\mathrm{2}}$ plasma treatment for the etched samples effectively removed the etch-induced defects and damage on the surface, leading to improved surface morphology, photoluminescence, and ohmic contact in n-type GaN.