High-Precision Characterization of Super-Multiperiod AlGaAs/GaAs Superlattices Using X-Ray Reflectometry on a Synchrotron Source

The morphology of supermultiperiod Al 0.3 Ga 0.7 As/GaAs superlattices grown by molecular-beam epitaxy has been determined using X-ray reflectometry (including the one on a synchrotron source) and photoluminescence. The layer thicknesses of a superlattice with 100 periods determined in laboratory and synchrotron studies correlate with an error of ~1%. Reflection peaks, which are not observed in measurements on a diffractometer and are likely related to the technological growth features of these structures, are revealed on a synchrotron beginning with high (>4–5) Bragg orders. It is analytically shown that these peaks correspond to modulation in the superlattice with a period that is three to five times larger and characterize the thickness dispersion over the structure depth of a few percent.