Deep Levels and Electron Paramagnetic Resonance Parameters of Substitutional Nitrogen in Silicon from First...

Area of Science:

• Materials Science
• Solid-State Physics
• Computational Materials Science

Background:

• Nitrogen implantation in silicon suppresses interstitial diffusion and void formation.
• Spectroscopic identification of specific nitrogen-related defects, like substitutional nitrogen (NSi), is challenging.
• Existing studies link the SL5 electron paramagnetic resonance signal to NSi but lack clarity on its thermal behavior.

Purpose of the Study:

• To establish a comprehensive theoretical model for substitutional nitrogen (NSi) in silicon.
• To elucidate the symmetry-breaking mechanism and fundamental physical properties of NSi.
• To resolve the debate surrounding the metastability of the NSi center.

Main Methods:

• Ab initio calculations to model the energy landscape and physical properties of NSi.
• Density Functional Theory (DFT) based approaches to compute Electron Paramagnetic Resonance (EPR) parameters (g and A tensors).
• GW method calculations for thermodynamic charge transition levels.

Main Results:

• A theoretical picture of substitutional nitrogen (NSi) based on its symmetry-breaking mechanism.
• Calculated EPR parameters (g and A tensors) that clarify the metastability of NSi.
• Reference values for the donor and acceptor levels of NSi computed using the GW method.

Conclusions:

• The study provides a robust theoretical framework for understanding substitutional nitrogen (NSi) in silicon.
• The calculated EPR parameters and charge transition levels offer crucial data for defect identification and characterization.
• This work resolves ambiguities regarding the metastability of NSi, advancing defect physics in nitrogen-doped silicon.