Growth studies of pseudomorphic GaAs/InGaAs/AlGaAs modulation-doped field-effect transistor structures

Strained GaAs/InGaAs/AlGaAs quantum well structures have been grown by molecular beam epitaxy at substrate temperatures from 375 to 510 °C. The well layer thickness and In composition are analyzed by ion channeling and particle-induced x-ray emission as a function of growth temperature. Test structures for modulation-doped field-effect transistors grown at 375 and 510 °C under two different As₄ overpressures were also characterized by Van der Pauw measurements and low-temperature photoluminescence. The observed differences in film quality can be explained by the influence of substrate temperature and As₄ flux on the cation surface mobility during growth of the InGaAs layer.