Determination of the layer structure of embedded strained InGaAs multiple quantum wells by high resolution x-ray diffraction

High resolution x-ray diffraction (HRXRD) has been used to determine the layer compositions and thicknesses of compressively strained InGaAs multiple-quantum-well (MQW) structures embedded in thick cladding layers that are nominally lattice matched to InP. The entire layer structure was accurately determined from the results of HRXRD measurements for a simple strained MQW structure in which barriers and claddings are of the same composition. The estimated margins of error are less than 1% for the quantum-well indium composition and ±2.5 Å for well and barrier thicknesses. The layer structure of the active region in a complete InGaAlAs graded-index separate confinement strained MQW laser diode has also been determined by HRXRD.