Homogeneous Amorphization in High-Energy Ion Implanted Si

We have investigated amorphization mechanisms in 5 MeV ${\mathrm{Si}}^{+}$ ion implanted Si using cross-sectional transmission electron microscopy (XTEM) measurements. Both microdiffraction patterns and high-resolution XTEM images of the amorphous/crystalline (a/c) Si interface region indicate that the a/c interface is very sharp and the amorphous Si transition occurs within a few atomic layers. Image simulations based on the divacancy and di-interstitial (D-D) pair model [Phys. Rev. B 49, 16 367 (1994)] suggest that an accumulation of the D-D pairs gives rise to homogeneous amorphization in ion implanted Si.