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 oxidatio n and identify the oxide phase formed as a consequence of the oxidatio n of AlAs to be gamma-Al2O3, with the cubic Fd 3m 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 oxid ation front along the porous interface. (C) 1996 American Institute of Physics.