Sb doping of Si molecular-beam epitaxial layers: Influence of the substrate misorientation

The influence of the misorientation of the surface on the doping of Si(111) by Sb under codeposition in a molecular-beam epitaxy chamber is experimentally evidenced by secondary ion mass spectrometry measurements. The Sb incorporation presents the same qualitative behavior (it is almost constant down to a critical temperature, below which it abruptly increases) for flat and misoriented substrates, but with a shift towards lower temperature in the latter case. This can be understood in terms of local equilibrium, as the result of the coupling between desorption and segregation phenomena during the incorporation process. The difference between the nominal and vicinal substrates is then ascribed to the existence of a temperature range [700°C-780 °C] for which desorption essentially concerns Sb atoms adsorbed on step sites.