Ultra shallow layer formation in silicon (001) by the use of recoil implantation

Recoil implantation was performed to create ultra shallow Sb doped layers in Si (001) substrates. The technique consisted of the initial deposition of thin (40 nm to 140 nm) Sb layers on a Si (001) substrate wafer followed by high energy Ar+ ion irradiation and final chemical stripping of the residual Sb film. The resulting Sb atoms were recoil implanted into the underlying Si substrate. The results obtained showed a linear dependence of the Sb areal density with the Ar+ ion dose over the dose range of 5 x 1015 cm-2 to 8 x 1016 cm-2. The Sb areal density was also found to have a linear dependence with the Ar+ ion energy over the range from 125 keV to 200 keV.; The Sb doped layer width was measured with the use of Medium Energy Ion Scattering and found to have a Full Width Half Max of 4 nm. This led to the indication that only Sb atoms at or near the Sb-Si interface were implanted in the underlying Si substrate. Computer simulations using the Transport of Ions in Matter program support this by showing that only very low energy transfers to the Sb atoms are occurring on the order of 60 eV/atom.; The deposited Sb layer thickness was also shown to be a weakly dependent parameter in determining the Sb areal density for a given ion energy and dose. Results show identical Sb peaks over the deposited layers of 43 nm to 75 nm.; Rapid thermal annealing (RTA) was performed with the results showing regrowth of the Si substrate, but no substitutional placement of the Sb atoms. This was most likely due to inadequacies in the RTA equipment.