Structural characterization of an Sb delta-doping layer in silicon

Delta-function doped layers in Si have been prepared by deposition of Sb on Si(001) followed by solid phase epitaxy of Si. The morphology and the crystal quality of the grown structures are characterized in situ during all stages of preparation by high-resolution Rutherford backscattering spectrometry. The obtained doping profile is found to consist of a <0.8-nm-wide spike and a 4-nm-long tail in front of the spike. A large fraction of about 70% of the Sb atoms is confined to the spike while the remaining 30% is located in the tail. Ion channeling and blocking measurements demonstrate that at least 95% of the Sb atoms is located on substitutional lattice sites. At temperatures exceeding 1000 K, the Sb profile broadens and Sb atoms diffuse towards the surface where they desorb.