Determination of the Electron Beam-Induced Shrinkage Rates Of Isolated Amorphous Zones In Germanium

Epitaxial regrowth of isolated amorphous zones, created in Ge by implantation with 50 keV Xe+ ions, was stimulated at room temperature by using electron beams with an energy below that required to create Frenkel pairs. The process was studied by using transmission electron microscopy combined with an automatic computer image analysis program, and the regrowth was characterized by determining the shrinkage rate of the effective radius of individual zones. The effective radius decreases approximately linearly with electron dose. The regrowth rate of irregular shaped amorphous zones is fast initially and slows as the shape of the amorphous zone becomes more regular. Only one regrowth rate is found for amorphous zones with a regular shape. The regrowth rate increased with decreasing energy below the threshold displacement voltage, suggesting that electronic excitations are able to induce epitaxial growth.