  Solid-phase epitaxial crystallization of amorphous Si layers on a crystalline
Si substrate during B-ion irradiation is investigated over the temperature
range 293 - 573 K. Regrowth occurs at all measured temperatures, with
activation energy 0.07 eV and prefactor 2.36 nm / 10^14 B cm-2 The low
activation energy suggests that free interstitial point defects are involved
and the unusually large prefactor indicates that each interstitial crystallizes
about 50 host Si atoms. We propose that interstitial annihilation at the a/c
interface sets off a shock-like process that drives c-Si island nucleation and
growth until terminated by misfit strain.
