Transient Growth-Rate Change During Gas-Source Molecular-Beam Epitaxy Of Si1-Xgex Alloys

Reflection high-energy electron diffraction intensity oscillations during gas source molecular beam epitaxy growth of Si1-xGex using disilane and germane are reported. Transient changes of the oscillation period and hence the growth rate are observed during the growth. Their origin is discussed on the basis of hydrogen desorption kinetics on the alloy surface and attributed to Ge surface segregation effects at the growth interface. This observation provides a unique opportunity for in situ investigations with monolayer-scale resolution, of Ge segregation effects in Si/Si1-xGex heterostructures.