The formation of P+/N shallow junctions for 0.18 μm technology requires the incorporation of dopant atoms, e.g., boron, at a depth of 540±180 Å below the surface of the crystal. This is done 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. Decaborane was implanted at 4 and 7 keV and doses of 1E13 and 1E14 cm-2. Junctions with depth ≪600 Å and sheet resistance of 480 Ω/◻ have been demonstrated. Annealed samples were also examined using high-resolution cross-section transmission electron microscopy. Molecular ion implantation of Si using decaborane has been simulated using molecular dynamics at energies between 4 and 1 keV per molecule. The simulation shows local swelling resulting from individual molecular impact, and hydrogen is also implanted into silicon. © 2000 American Vacuum Society.