In situ monitoring of AlGaAs compositions and GaAs growth at high temperature by spectroscopic ellipsometry and desorption mass spectroscopy

In situ spectroscopic ellipsometry has been used in conjunction with desorp tion mass spectrometry to determine both the composition of Al and growth r ate of AlxGa1-xAs and GaAs at high temperatures (600-720 degrees C). Ex sit u cross sectional transmission electron microscopy verified the AlGaAs/GaAs layer thicknesses grown by molecular beam epitaxy at these elevated temper atures. The substrate temperature dependence on Ga desorption rates, given the As, Ga, and Al fluxes and V/III flux ratios, was examined by Monte Carl o simulation. These simulations showed goad agreement with the experimental results. (C) 1999 American Vacuum Society. [S0734-211X(99)00603-4].