It was recalled that it had recently been found that amorphization was induced in Si by electron irradiation. By systematically examining the amorphization, the diagram of steady states under electron irradiation, either amorphous or crystalline Si established as a function of incident electron energy, electron dose and irradiation temperature. Utilizing transmission electron microscopy, electron energy filtered diffraction and electron energy-loss spectroscopy, the atomic structure, the electronic structure, and the thermal stability of amorphous Si induced by electron irradiation were characterized. On the basis of the experimental data, it was also concluded that the amorphization was caused by the accumulation, not of point defects, but of small amounts of cascade damages. By analyzing the change in the intensity of halo diffraction rings during amorphization, it was clarified that the smallest cascade damage which contributed to amorphization included only about four Si atoms. This presumably supports the amorphization mechanism that 4 self-interstitial atoms form the quasi-stable structure I4 in c-Si and it became an amorphous embryo.

Elemental Process of Amorphization Induced by Electron Irradiation in Si. J.Yamasaki, S.Takeda, K.Tsuda: Physical Review B, 2002, 65[11], 115213 (10pp)