Selective Wet Etching of GaInP , GaAs , and InP in Solutions of HCl , CH 3 COOH , and H 2 O 2

Abstract

The wet chemical etching of , , and in solutions of has been evaluated. In the absence of the oxidant, , the solutions etch and with high selectively over but rough surfaces are formed. When is added, smoother surfaces are obtained and depending on the concentration, the etchant can be made highly selective for . The etch rate of these mixtures varies strongly with the age of the solution, initially increasing and then gradually declining. The increase in etch rate is attributed to the formation of in solution from the reaction of with , and the eventual decrease in etch rate to the gradual evaporation of from solution. The in these mixtures functions as a nonaqueous solvent. In dilute solutions slow etch rates and smooth surfaces can be obtained for all three materials, suggesting that this etchant may be useful for recessing layers for heterostructure electronic and optoelectronic device applications.