Development of hybrid tight-binding quantum chemical molecular dynamics method and its application to boron implantation into preamorphized silicon substrate

The precise control of the thickness of amorphous layers and concentration of dopant atoms in thin layers is important for the fabrication of ultrashallow highly doped junctions. It was reported that amorphous layers suppress the channeling tail of implanted boron atoms. In this work, we studied the dynamics of boron implantation into a silicon substrate preamorphized by Ge irradiation, using our novel hybrid tight-binding quantum chemical molecular dynamics method. We have implemented a dynamic hybridization method in our study of preamorphization and implantation, in which a focused atom changes its position with simulation time. In the developed dynamic hybridization method, the region treated by the quantum chemistry method can dynamically change with simulation time. We have successfully applied the developed method and observed that the decrease in the kinetic energy of the implanted boron atom is correlated with the formation of chemical bonds between the implanted boron atom and the surrounding silicon atoms.