($\sqrt 3 \times \sqrt 3$)B Structure Covered with Molecular Beam Epitaxial Si

Abstract

The electric activation efficiencies for the a-Si/B$\sqrt 3 \times \sqrt 3$Si(111) system was measured by Hall measurement. The result strongly suggests that almost all boron atoms are activated at the a-Si/Si(111) interface because of the $\sqrt 3 \times \sqrt 3$ structure formation. A ($\sqrt 3 \times \sqrt 3$)B structure was also found to be formed on a (5×5) Ge_xSi_1−x/Si(111) surface on which Ga or Sn atoms did not form any superstructures. A Si epitaxial over-layer can be grown on the ($\sqrt 3 \times \sqrt 3$) B/50A Ge_θ.4Si_θ.6/Si(111) structure at a growth temperature of 300 °C while preserving a large fraction of ($\sqrt 3 \times \sqrt 3$)B structure due to strain compensation.