Oxygen‐induced Al surface segregation in AlxGa1−xAs and the effect of Y overlayers on the oxidation of the Y/AlxGa1−xAs interface

The oxidation of AlxGa1−xAs (x=0.15, AlGaAs) was studied by Auger electron spectroscopy and x‐ray photoelectron spectroscopy at 350 °C and different oxygen exposures (up to 5×104 L). Also studied were the effects of yttrium overlayers (θ=3 ML) on the oxidation of the AlGaAs surface. Substantial oxygen‐induced Al surface segregation has been observed for both yttriated and non‐yttriated AlGaAs surfaces which increased with increasing oxygen exposure. Also observed is a significant Y‐enhanced oxidation of the AlGaAs surface. Oxidation of the yttriated AlGaAs surface was found to be a factor of 4 greater than that of the non‐yttriated surface. Also, while oxidation of the non‐yttriated AlGaAs yielded mainly Al2Ox (x<3) and only little Ga2O3, the yttriated AlGaAs surface oxide layer was principally Ga2O3 and stoichiometric Al2O3. However, both the yttriated and non‐yttriated surfaces were found to contain metallic As within the oxide layer.