J. Nakata, EVIDENCE OF ENHANCED EPITAXIAL CRYSTALLIZATION AT LOW-TEMPERATURE BY INELASTIC ELECTRONIC SCATTERING OF MEGA-ELECTRON-VOLT HEAVY-ION-BEAM IRRADIATION, Journal of applied physics, 79(2), 1996, pp. 682-698
The inelastic electronic scattering of Kr-84 at energies of 0.5-5 MeV
and Xe-131,Xe-132 ions at energies of 1-5 MeV is directly confirmed to
play a role in the ion-beam-induced epitaxial crystallization (IBIEC)
of amorphous Si layers on crystalline Si substrates at 310-450 degree
s C. The crystallization rate per unit vacancy (normalized crystalliza
tion rate) created by the elastic nuclear scattering of the incident i
on beam at the amorphous-crystalline (a/c) interface is increased 40%-
50% by increasing the inelastic electronic scattering three- to fourfo
ld while maintaining the same elastic nuclear scattering conditions at
the a/c interface. This normalized crystallization rate also increase
s with the inelastic electronic scattering at the a/c interface. Howev
er, the percentage of increase falls to about 20% as the absolute valu
e of the inelastic electronic energy loss at the a/c interface decreas
es to below about 20 keV/ion/(20 nm) or as the number of vacancies cre
ated at the a/c interface increases to more than 250/ion/(20 nm). At 3
10-450 degrees C the activation energy for IBIEC induced by Kr or Xe i
rradiation is 0.5-0.6 eV. This value slightly larger than the 0.2-0.3
eV reported for temperatures below 300 degrees C reflects the thermall
y activated solid-phase epitaxy. The mechanism of this enhanced crysta
llization by inelastic electronic scattering is discussed qualitativel
y. (C) 1996 American Institute of Physics.