Ridge waveguide multiple quantum well laser diodes in which the ridge
heights are predetermined by etch stop layers have been fabricated for
the first time in InGaAlAs materials lattice-matched to InP. A 3 nm t
hick pseudomorphic AlAs layer forms the etch stop layer in these devic
es and the selective etching was performed by a succinic acid solution
that etches InGaAs and InAlAs but not AlAs. With this technique, more
reliable and uniform ridge stripe device fabrication is expected.