Temperature dependent etching of Gallium Nitride layers grown by PA -MBE

Future of microwave, power and photonics industry is focused on GaN due to its extraordinary material properties such as wide and direct band gap, large thermal and chemical stability, high breakdown voltage, high saturation velocity. Formation of devices for these applications requires a material selective etching which is performed via wet-etching process. In this paper, temperature dependent etching properties of GaN have been revealed. Molten KOH has been employed as an etchant, to etch 2 µm MBE grown GaN layer on Silicon (111). To verify temperature dependence of GaN etching, etching has been performed at a fixed concentration and etching time. Optimum temperature to etch GaN completely has been determined from Arrhenius plot of etch rate vs temperature. Etch depth has been determined from AFM, whereas, morphology has been confirmed using SEM.