Photoelectrochemical etching of InxGa1-xN

Photoelectrochemical (PEC) etching of InxGa1-xN in the KOH solution under i llumination of a Hg-arc lamp is studied. An indium oxide surface layer is f ormed during PEC etching, which slows down the etching rate. The PEC etch r ate of InxGa1-xN is determined by dissolution of indium oxides into the sol ution. Increase of the solution temperature results in an increase of solub ility of indium oxides and thus enhances the PEC etch rate. It is found tha t stirring the solution can accelerate indium oxides to dissolve into the s olution and increase the etch rate. The thick indium oxide layer on the PEC -etched InxGa1-xN surface can be effectively removed by the treatment of us ing a hot 6N HCl solution. A post-treatment by using a 3.2 M KOH solution c an provide a smooth sidewall on the PEC-etched surface for the potential ap plication to laser cavity. (C) 2000 American Institute of Physics. [S0003-6 951(00)05025-7].