We demonstrate well-controlled crystallographic etching of wurtzite GaN grown on c-plane sapphire using H3PO4, molten KOH, KOH dissolved in ethylene glycol, and NaOH dissolved in ethylene glycol between 90 and 180 °C, with etch rates as high as 3.2 μm/min. The crystallographic GaN etch planes are 0001, 101̄0, 101̄ 1̄, 101̄2̄, and 101̄3. The vertical 101̄0 planes appear perfectly smooth when viewed with a field-effect scanning electron microscope. The activation energy is 21 kcal/mol, indicative of reaction-rate limited etching.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)