Jiro Matsuo

Formation of shallow junctions using decaborane molecular ion implantation; comparison with molecular dynamics simulation

The formation of P/sup +//N shallow junctions requires the incorporation of boron atoms at depths closer to the surface of the crystal. This is done commonly by implanting boron ions at low energies. Another approach for forming shallow junctions involves, in principle, implanting large molecular ions accelerated to higher energies but with an equivalent low energy per boron atom. Molecular ion implantation of Si using decaborane has been simulated using molecular dynamics (MD) at energies between 4 keV and 4 keV per molecule. The simulation shows local swelling resulting from individual molecular impact and hydrogen is also implanted into silicon. Decaborane was implanted at 4 keV and 7 keV at doses of 1E13 and 1E14 cm/sup -2/. Junctions with depth <600 /spl Aring/ and sheet resistance of 480 /spl Omega///spl square/ have been demonstrated.