Formation of buried a-Si/Al/Si, a-Si/Sb/Si and a-Si/B/Si interfaces and their electrical properties

Si:Al, Si:Sb and Si:B surface phases capped by amorphous Si layers were grown by MBE. The formation of the buried interfaces was studied by low-energy electron diffraction and Auger electron spectroscopy which revealed that, except for the stable Si(111)root 3 X root 3-B, the majority of the surface phases suffer either from in-plane redistribution (i.e. break-up of surface reconstruction) or surface segregation of the dopant atoms. The electrical characterization of the grown samples included conductivity and Hall effect measurements between 20 and 300 K. It was found that, while the buried Si(111)root 3 X root 3-B shows metallic behaviour, the buried Si:Al and Si:Sb surface phases-show negligible activation of dopants.