Atomic rearrangements in HfO2/Si1-xGex interfaces

Atomic exchanges across the interface between a HfO2 thin film and strained semiconducting Si1-xGex (x=0.1, 0.2, and 0.3) was investigated by extended x-ray absorption fine structures. Atomic layer deposition of HfO2 films on epitaxial Si1-xGex produces a Hf-silicate (Hf-O-Si bond) phase at the interface. Also O atoms diffuse into the Si1-xGex alloy to form Ge oxide in a segregated phase. This tendency becomes evident when the Ge concentration of the substrate becomes higher or when HfO2 is deposited and these samples are compared to the pure Si1-xGex substrates which have been exposed to ambient atmosphere. (c) 2006 American Institute of Physics.