Spectroscopic Ellipsometry Analysis of Rapid Thermal Annealing Effect on MBE Grown GaAs1−x−Nx

We report on the effect of rapid thermal annealing (RTA) on GaAs1−x−Nx layers, grown by molecular beam epitaxy (MBE), using room temperature spectroscopic ellipsometry (SE). A comparative study was carried out on a set of GaAs1−x−Nx as-grown and the RTA samples with small nitrogen content (x = 0.1%, 0.5% and 1.5%). Thanks to the standard critical point model parameterization of the GaAs1−x−Nx extracted dielectric functions, we have determined the RTA effect, and its nitrogen dependence. We have found that RTA affects more samples with high nitrogen content. In addition, RTA is found to decrease the E1 energy nitrogen blueshift and increase the broadening parameters of E1, E1+Δ1, E′0 and E2 critical points.