Comparison of the thermal interdiffusion phenomena in InGaAs/GaAs and InGaAs/AlGaAs strained heterostructures

The effect of 5 min high-temperature thermal annealing on InGaAs/GaAs strained superlattices and InGaAs/AlGaAs PHEMT structures grown by molecular beam epitaxy was studied using the Hall measurements, photoluminescence spectroscopy, and high-resolution X-ray diffraction. InGaAs/GaAs superlattices are shown to undergo photoluminescence peak energy blueshift after 700 °C annealing and distinguishable heterointerface roughening after 800 °C annealing. The magnitude of quantum well smoothing, caused by annealing induced III-group atom interdiffusion, was estimated experimentally using secondary ion mass spectrometry and X-ray reflectivity, and calculated from the modelled electron energy spectra in the diffused wells. InGaAs/AlGaAs PHEMTs appear to be more sensitive to annealing, demonstrating optical and structural changes of a similar nature to InGaAs/GaAs heterostructures, as well as transport properties degradation, at a wider range of annealing temperatures starting 500 °C.