Strain-driven diffusion process during silicon oxidation investigated by coupling density functional theory and...

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Silicon oxidation is fundamental to semiconductor manufacturing.
• Understanding oxygen diffusion mechanisms on silicon dioxide is critical for device performance.

Purpose of the Study:

• To investigate oxygen molecule reactions on oxidized silicon.
• To explore energy landscapes, barriers, and insertion mechanisms.
• To identify sublayer oxidation pathways.

Main Methods:

• Coupling density functional theory with Activation Relaxation Technique Nouveau (ART nouveau).
• Unbiased reaction pathway searching for potential energy surface exploration.
• Investigating oxygen molecule adsorption and diffusion on a silicon dioxide model-substrate.

Main Results:

• Strain energy increases with oxygen coverage.
• Oxygen diffusion kinetics at the Si/SiO2 interface are driven by strain.
• High oxygen coverage favors diffusion into deeper layers, unlike low coverage where interface reconstruction dominates.

Conclusions:

• Accumulated strain at high oxygen coverage facilitates atomic diffusion.
• Atomic diffusion at the interface releases strain, supporting layer-by-layer oxidation growth.
• Coverage-dependent energetics dictate the likelihood of atomic diffusion.