Microstructure of AlGaAs-oxide heterolayers formed by wet oxidation

We have carried out a transmission electron microscopy based study of AlGaAs-Al(oxide) heterolayers created by lateral sidewall wet oxidation and identify the oxide phase formed as a consequence of the oxidation of AlAs to be γ-Al2O3, with the cubic Fd3m structure. The oxide-semiconductor interface is weak and porous, possibly due to the high stress loads developed during oxidation, and we propose that the fast oxidation rates are a consequence of reactants transported to the oxidation front along the porous interface. © 1996 American Institute of Physics.