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 wer e 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 maj ority of the surface phases suffer either from in-plane redistribution (i.e. break-up of surface reconstruction) or surface segregation of t he 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 neg ligible activation of dopants.