NOVEL, ORGANIC ACID-BASED ETCHANTS FOR INGAAIAS/INP HETEROSTRUCTURE DEVICES WITH AIA ETCH-STOP LAYERS

Several organic acids have been identified that enable the etching of indium compounds, while maintaining selectivity with respect to AlAs, and these acids have been used to develop InGaAlAs etching solutions that allow the selective etching of InP lattice-matched InGaAlAs heterostructures using thin pseudomorphic AlAs layers as etch stops. Of the organic acids tested, the nonaromatic, polycarboxylic acids have been found to be most effective, and some of the best results have been obtained for etchants consisting of succinic acid, ammonia, and hydrogen peroxide. It is found that the etch rate of In0.53Ga0.47As with this solution can be as much as 1000 times the etch rate of AlAs, while the etch rate of In0.52Al0.48As can be as much as 500 times that of the AlAs.