Atomistic Computer Simulations on Ion Beam Synthesis and Decay of CoSi2 Nanowires

Nanowires (NWs) and chains of nanocrystals (NCs) embedded in dielectrics or semiconductors are intensively studied regarding their potential application in nanoelectronics. CoSi2 nanostructures in Si are particularly interesting because of the full compatibility of CoSi2 with CMOS technology.
Here, we present predictive atomistic computer simulations on the ion beam synthesis of CoSi2 NWs in Si and their decay into chains of CoSi2 NCs which are applicable as plasmon waveguides. In order to simulate the Co implantation, the binary collision codes TRIDYN and TRIM were adapted to the particular experimental situation of a finely-focused Co ion beam of 50nm in width. The resulting 3D implantation profile serves as input for a kinetic lattice Monte-Carlo code by means of which nucleation and growth of CoSi2 precipitates and their coalescence into a CoSi2 NW are described. From an evolutionary viewpoint, NW synthesis and decay proceed on different time scales. The NW decay into a NC chain (Rayleigh instability) is driven by the minimization of interfacial free energy. In this regard, it will be demonstrated that the orientation of the Co implantation profile to the single crystalline Si matrix influences the stability of the synthesized CoSi2 NW. Since the system energetically favors the CoSi2(111)/Si(111) interface, driving faceting forces may occur which accelerate the NW decay into a NC chain.