Kinematic versus dynamic approaches of x-ray diffraction simulation. Application to the characterization of InGaAs/InGaAlAs multiple quantum wells

A comparison of kinematic and dynamic approaches of x-ray diffraction is made for multiple InGaAs/InGaAlAs quantum wells (MQW), around 002 and 004 reflections, as a function of strain and thickness. A domain of validity of the kinematic approximation is then defined. It turns out that the kinematic approximation is sufficient in the case of typical structures for MQW lasers or modulators. An automatic procedure including kinematic treatment of double-diffraction X and photoluminescence data is proposed, which allows us to determine precisely the compositions, thicknesses, and even the band offsets of MQW structures. This procedure is applied to a 20 period sample. The results are confirmed by transmission electron microscopy measurement.