Spontaneous Change of Growth Orientation of InGaP/GaAs Superlattices in MBE

Abstract

ABSTRACTThe influence of growth interruption during the MBE growth of (100) In0.5Ga0.5P/GaAs superlattices is investigated by cross-sectional TEM. It is observed that for certain combinations of interruption lengths and group V fluxes, the growth orientation of the superlattice changes spontaneously from [100] to <311> direction. V-shaped grooves with {311} facets form initially in the growth plane and eventually lead to the formation of regions of {311} superlattice structures. The direction of V-shaped grooves is along the [011[ axis, which is parallel to the surface dangling bonds of the group V atoms in the unreconstructed (100) plane. The most critical stage for the spontaneous change of the growth orientation is the interruption after the growth of a GaAs layer with the P2 flux. Our observations suggest that small but stable {311} facets form at this stage and develop into well-defined {311} growth planes during the growth of the GaAs layer.