Related Experiment Videos
Molecular dynamics simulations of silicon-fluorine etching
A Darcy1, A Galijatovic, R Barth
1Department of Chemistry, College of Charleston, South Carolina 29424, USA.
Journal of Molecular Graphics
|October 1, 1996
Summary
Molecular dynamics simulations reveal how fluorine atoms etch silicon surfaces. Different potentials significantly impact reaction predictions, with a newly discovered SiF4 formation mechanism at higher energies.
Area of Science:
- Surface Science and Chemistry
- Computational Materials Science
- Etching Processes
Background:
- Silicon-fluorine etching is crucial for semiconductor manufacturing.
- The reactive layer involves fluorosilyl adspecies (SiF, SiF2, SiF3).
- Understanding reaction mechanisms and products is key.
Purpose of the Study:
- Investigate reactions between gaseous fluorine and silicon adsorbates on Si(100).
- Determine how adsorbate identity, kinetic energy, and potential functions affect etching products.
- Compare simulation results using SW and WWC potentials.
Main Methods:
- Molecular dynamics simulations of F(g) + (SiFx)n(a) reactions.
- Utilized the SW potential and its WWC reparameterization.
- Simulated three specific reactions: F + SiF3, F + SiF2-SiF3, and F + SiF2-SiF2-SiF3.
Main Results:
- SiF4 is the major product; Si2F6 and Si3F8 are minor and prone to fragmentation.
- An SN2-like mechanism dominates SiF4, Si2F6, and Si3F8 formation.
- A novel SiF4 formation mechanism via Si-Si bond insertion was observed at higher energies.
- The SW potential predicted lower reaction thresholds and higher cross-sections than WWC.
Conclusions:
- Potential energy function parameterization significantly influences simulation outcomes.
- The SW potential overestimates reactivity compared to experimental data.
- Simulation insights aid in understanding and optimizing silicon-fluorine etching processes.