Wet Etching of β-Ga2O3 Substrates

Wet etching of (100)-oriented beta-Ga2O3 single crystal substrates was carried out using H3PO4 and H2SO4. The etching reactions followed the Arrhenius equation, but the etching in H2SO4 at a high temperature of 190 degrees C was disturbed by the formation of sulfates on the surface. Considering the higher etching rate over the temperature range of 100-194 degrees C, H3PO4 is more preferable as an etchant for beta-Ga2O3. Although the isotropic etching led to side etching, a grid pattern in the order of pm was successfully fabricated. These results indicate that this simple and low-cost wet etching using H3PO4 is suitable for isolating devices or patterning structures on beta-Ga2O3 substrates. (c) 2009 The Japan Society of Applied Physics