Atomistic modeling of solid phase recrystallization of amorphous Si and Ge

Recrystallization of amorphous Si and Ge continues to be an important issue in nanoelectronic technologies. In order to obtain high dopant concentrations in the nanoscale regions ion implantation at relatively high fluence is required which causes the amorphization of the host material. Subsequently, thermal processing must be used to restore the semiconductor crystal. In planar structures this can be fully achieved by solid-phase epitaxial recrystallization whereas more complex processes take place in fins and nanowires due to the significant influence of surfaces and interfaces. It is highly desirable to understand the recrystallization phenomena on the atomic level. This work presents results of molecular dynamics simulations of solid phase recrystallization in Si and Ge. At first the process of epitaxial recrystallization of amorphous layers is considered and the influence of accuracy of the interatomic potential used in the simulations is discussed. Then the method is ap plied to solid phase recrystallization of fins and nanowires. The incomplete restoration of the host crystal is characterized by the occurrence of defects, stacking faults and polycrystallization.