Effects of attractive potential between ultra-low energy boron and silicons and boron diffusion in the beginning of annealing: Molecular dynamics study

Abstract

We have investigated effects of attractive potential between ultra-low energy boron and silicons using molecular dynamics simulation. For B-Si, we use the Stillinger-Weber (SW)-type interatomic potential. For strong repulsive interaction at short interatomic distance, we use the Ziegler, Biersack, and Littmark (ZBL) potential with the repulsive part of the term being splined to SW-type B-Si potential. Molecular dynamics simulation using proposed potential revealed more scattering angles than that using ZBL, since collision time using proposed potential was longer than that using ZBL. Because thin films by low energy ion beams have been important to fabricate gigantic-scale-integragted (GSI) devices, molecular dynamics study about ion beam processes should include attractive potential. At 1000 K similar to 1300 K, calculated diffusivities nearly were 10(-7) cm(2)/s and Arrhenius relationship with temperature. In the beginning of annealing, boron diffusivities were very high, since the damages formed by ion implant were rapidly dissolved, many Si interstitials are generated, and borons are swiftly diffused.