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

Abstract

In this work we present an in situ investigation of the interface composition between an In 0.53Ga 0.47As substrate and an Al 2O 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 Å 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.