ION-IMPLANTATION MODEL CONSIDERING CRYSTAL-STRUCTURE EFFECTS

An ion implantation model for crystalline targets is proposed. The model is based on the Monte Carlo method. Ion behavior is determined by directly referring to three-dimensional crystal structure data. Both channeling and dechanneling can be well simulated by modeling many-body scattering with lattice atoms and introducing atom thermal vibration effects. This model was applied to simulate low-energy boron implantation in crystal silicon. Significant boron distribution tail spreading is predicted due to subchanneling effects, even if the ion beam is tilted and/or the crystal surface is covered with amorphous layers. These predictions agree with experimental data. Amorphization effects on two-dimensional boron distribution were also investigated. It was predicted that locally insufficient pre-amorphization causes marked lateral spreading of boron. © 1990 IEEE