Crystallization of spatially isolated amorphous zones in Si, Ge, GaP, InP
and GaAs was stimulated thermally and by irradiation with electrons and
photons. The amorphous zones were created by a 50 keV Xe+
implantation. Significant thermal crystallization occurred at temperatures
greater than 425 K, 375 K and 200 K in Si, Ge and GaAs, respectively.
Electrons with energies between 25 and 300 keV stimulated crystallization in
all materials at temperatures between 90 K and room temperature. For
electron energies above the displacement threshold, the crystallization rate
decreased as the electron energy decreased. As the electron energy was
decreased below approximately 100 keV, the crystallization rate unexpectedly
increased. The crystallization rate was independent of temperature for all
electron irradiations. Irradiation with a 532 nm green laser
(hv= 2.33 eV) caused crystallization in Si
(Eg = 1.11 eV) and Ge (Eg = 0.67 eV) at a rate comparable to a thermal anneal at 425 K
and 375 K, respectively, and caused minimal crystallization in GaP
(Eg = 2.26 eV). The electron and photon irradiation results are
consistent with the model that crystallization is controlled by defects
(dangling bonds and kinks) created by electronic excitation at the
amorphous-crystalline interface.