Structural evolution in Ge+ implantation amorphous Si

The structural evolution in Ge+ implantation amorphous Si has been investigated by high-resolution transmission electron microscopy in conjunction with auto-correlation function (ACF) analysis. Si(0 0 1) wafers were implanted with 5 keV Ge+ to a dose of 5×1015 ions/cm2. A high density of embedded nanocrystallites was found to be present in as-implanted amorphous Si. After 350 °C annealing, the density of nanocrystallites was found to decrease, but increase after annealing at 400 °C or higher temperatures. The observation indicated that the implanted silicon became more randomized upon annealing up to 350 °C. The results are discussed in terms of energy variation in the system.