Solid phase recrystallization of Si nanowires


Solid phase recrystallization of Si nanowires

Posselt, M.; Liedke, B.; Baldauf, S.

Advanced Si and Ge nanowire transistors can be produced by top-down or bottom-up approaches. In order to obtain the desired electrical properties doping of the nanowires is required. Ion implantation is one of the favored methods to introduce dopant atoms in a controlled manner. If relatively high ion fluences are needed the originally single-crystalline nanowire is amorphized. Subsequently, thermal processing must be used to restore the Si or Ge crystal and to activate the dopants electrically. In planar structures a complete restoration can be achieved by solid-phase epitaxial recrystallization, whereas more complex processes take place in nanowires, due to the significant influence of surfaces and interfaces. In order to understand the solid-phase recrystallization in such confined systems molecular dynamics simulations are performed. Partially amorphized nanowires embedded in a matrix as well as free nanowires and nanopillars are considered. In dependence on whether embedded or free nanowires are investigated several phenomena are observed, such as stacking fault and twin formation, random nucleation of separate crystalline grains, as well as edge rounding and necking. The simulation results are in qualitative agreement with experimental findings.

Keywords: Solid phase recrystallization; Si nanowires; Molecular dynamics simulation

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Publ.-Id: 21046