Reactive force field potential for carbon deposition on silicon surfaces

Area of Science:

• Materials Science
• Computational Chemistry
• Surface Science

Background:

• Accurate interatomic potentials are crucial for simulating material deposition processes.
• Existing potentials may not fully capture the reactive nature of carbon-silicon interactions.

Purpose of the Study:

• To implement and validate a new reactive interatomic potential for molecular dynamics simulations of carbon deposition on silicon.
• To investigate the influence of deposition parameters on the carbon deposition process.

Main Methods:

• Development of a third-order reactive force field based on the Kieffer force field, incorporating dynamic charge transfer and bond dynamics.
• Optimization of Si-C and C-C interaction parameters using a genetic algorithm.
• Molecular dynamics simulations of carbon deposition on reconstructed silicon (100) surfaces, comparing the new potential with a Tersoff-like potential.

Main Results:

• The new Kieffer-based potential accurately models silicon carbide and diamond properties and defect formation energies.
• Simulations revealed a channelling effect of carbon deposition on silicon surfaces, particularly at a 45° incidence angle, due to surface channels.
• Sticking coefficients varied between 73% and 100% depending on deposition conditions on a pristine silicon surface.

Conclusions:

• The implemented Kieffer force field is suitable for molecular dynamics simulations of carbon deposition on silicon surfaces.
• The study highlights the importance of incidence angle and reveals a channelling phenomenon affecting carbon deposition.
• The developed potential offers a valuable tool for understanding and optimizing carbon-silicon material growth.