Separation of Ga-polar GaN layer from Si substrate by wet chemical etching

In this work the effects of H3PO4:CH3COOH:HNO3:HF etching solution taken with different concentrations to the Ga-polar GaN/SixNy/Si(111) epitaxial structures is investigated. Possibility of at least partial separation of Ga-polar GaN film from the silicon substrate without any GaN surface morphology changes by the selected etchants is demonstrated. The etching process mechanism is shown. Resistivity of the photoresist mask to etchants used in the experiments is found.