An energetic electron beam was used to stimulate the crystallization of spatially isolated amorphous regions at 30 or 300K. In these 4 materials, it was found that crystallization was induced even when the energy of the electron beam was lower than that required to create point defects in the crystalline structure. The rate of crystallization depended upon the material and upon the electron energy. In all of the materials, the rate decreased as the electron energy was increased from 50keV, and reached a minimum value at an electron energy that was slightly below the displacement threshold voltage. Above the displacement threshold, the re-growth rate again increased with increasing electron energy. Theoretical calculations suggested that heating effects were negligible, and this was confirmed by  in situ  ion implantation and electron irradiation at 30K; where sub-threshold electrons stimulated crystallization. The sub-threshold and low-temperature results were consistent with a model in which the crystallization process depended upon the creation of defects (dangling bonds, kinks) at the crystalline/amorphous interface. The crystallization that was stimulated by sub-threshold electron beams suggested that electronic excitation of the bonds along the crystalline/amorphous interface could induce the amorphous to crystalline transition.

I.Jencic, M.W.Bench, I.M.Robertson, M.A.Kirk: Journal of Applied Physics, 1995, 78[2], 974-82