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Atomistic Simulations of Silicon and Carbon Diffusion in Liquid Silicon

Camera J. Foster
Department of Materials Science & Engineering, University of Tennessee

This page shows visualizations of the diffusion of oxygen and silicon atoms in liquid silicon where 1% of the silicon atoms are replaced with oxygen atoms. This simulation was created using the Tersoff potential where the energy is based on a three-body interactions.

In crystal growth of silicon (Si), impurities such as carbon (C), nitrogen (N), and oxygen (O) are unwanted because they can compromise the performance of Si used as a substrate for many electronic devices, such as photovoltaics. Although the formation of impurities, such as SiC, SiO2, and Si3N4, in the Si melt is well known, diffusion coefficients of the impurity atoms are challenging to measure and require empirical potential based molecular simulations to predict. Using LAMMPS simulations of 1000 atoms, atomic simulations of 1 at% C, 1 at% O, and 1 at% Ge, in the Si melt were completed in order to determine the self-diffusion coefficients of the impurity atoms in liquid silicon. In addition to simulating the diffusion of different impurity atoms in the Si melt, the diffusion of C atoms in Si was determined using four different potential models: Tersoff, Erhart-Albe, Gao-Weber, and Vashishta. These values were compared with each other to determine which potential model agreed with published values the best.1,2,3

Interactive Structures

Color Legend:

  • Tan = silicon
  • Red = oxygen


1. J. Luo, A. Alateeqi, L. Liu, and T. Sinno, "Atomistic simulations of carbon diffusion and segregation in liquid silicon," Journal of Applied Physics, vol. 122, no. 22, p. 225705, 2017.

2. R. A. Logan and A. J. Peters, "Diffusion of Oxygen in Silicon," Journal of Applied Physics, vol. 30, no. 11, pp. 1627-1630, 1959.

3. M. Ogino, Y. Oana, and M. Watanabe, "The Diffusion Coefficient of Germanium in Silicon," physica status solidi (a), vol. 72, no. 2, pp. 535-541, 1982.

posted: April 2018.
updated: April 2018.