Computer image analysis of shrinkage of isolated amorphous zones in semiconductors induced by electron beam

Isolated amorphous zones were created in Ge by implantation with 50 keV Xe ions. Recrystallization of these zones was stimulated by irradiation with electrons having energy from 25 to 300 keV. The process was studied by using transmission electron microscopy (TEM) combined with a computer image analysis program. The regrowth was characterized by studying the evolution of the effective diameter of individual zones. Three distinct regimes have been observed. In the first, the effective diameter decreases linearly with electron dose, in the second the zone retains a constant size and in the third regime, the zone suddenly disappears. In the population of amorphous zones studied, some exhibited all three regimes of behavior, while for others only two regimes could be observed. A simple model of the regrowth mechanism is proposed to explain the observed results.