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

AIGaN/GaN mesa etching using different plasma combinations of Cl
₂
/Ar, Cl
₂
/BCl
₃
and Cl
₂
/CF
₄
by inductively coupled plasma was investigated. It was observed that the etch rate of Cl
₂
/Ar increases linearly with the Ar content. In contrast to the Ar-based mixtures, C
_l2
/BCl
₃
and Cl
₂
/CF
₄
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
/BCl
₃
plasma.