Al(2)O(3) stacks on In(0.53)Ga(0.47)As substrates: In situ investigation of the interface

In this work we present an in situ investigation of the interface composition between an In(0.53)Ga(0.47)As substrate and an Al(2)O(3) oxide grown by molecular beam deposition in ultra high vacuum conditions. In the effort to improve the chemical quality of the interface, reduction of semiconductor-oxygen bonding at the interface can be obtained by growing a few angstrom thick pure Al layer before starting exposure of the surface to the atomic oxygen flux. Conversely, when a Ge interface passivation layer is intercalated between the semiconductor and the oxide stack, the interface chemistry is governed by Ge reaction with other species (Al, O), leading only to a partial suppression of the interface oxides.