Si/SiO_2系における原子間力を再現するポテンシャルの開発

概要

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The molecular dynamics simulation has been widely applied to Si/SiO_2 systems, which are basic materials for the LSI technology. For the simulation, it is necessary to use accurate interatomic potential function, which reproduces the force acting on each atom. However, the validity of potential functions proposed has not been discussed in terms of the force. In this study, the force calculated by the Tersoff potential is compared with that obtained by an ab initio calculation in some snapshots of Si/SiO_2 systems at the temperature of 300K. It clarifies that the potential does not properly reproduce the force. Then, optimizing the parameters in the Tersoff potential on the basis of the force acting on each atom obtained by the ad initio calculation(Force matching method), two modified functions are proposed. One is"Potential A"obtained by optimizing the parameters for the Si crystal and the β-cristobalite SiO_2 crystal. The"Potential A"correctly reproduces not only the forces but also the lattice constants. The other in"Potential B"obtained by optimizing the parameters for a Si/SiO_2 interface model as well as the Si crystal and the β-cristobalite SO_2 crystal.The forces and lattice constants are successfully reproduced. Moreover, the"Potential B"gives a good result for the β-quartz SiO_2 , which is not used for the optimization. This implies the versatility of the proposed function.
一般社団法人日本機械学会の論文
2000-11-25