Etching of AIGaN/GaN HEMT structures by Cl2-based ICP

Abstract

AIGaN/GaN mesa etching using different plasma combinations of Cl₂/Ar, Cl₂/BCl₃ and Cl₂/CF₄ by inductively coupled plasma was investigated. It was observed that the etch rate of Cl₂/Ar increases linearly with the Ar content. In contrast to the Ar-based mixtures, C_l2/BCl₃ and Cl₂/CF₄ plasma combinations show a damage-free surface. Furthermore, the lowest isolation current values achieved in devices with reduced sheet resistance were achieved by using C_l2/BCl₃ plasma.