Dangling bond defects at Si-SiO2 interfaces: atomic structure of the P(b1) center

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Dangling bonds at Si-SiO2 interfaces are critical defects affecting electronic properties.
• Understanding these defects is crucial for semiconductor device performance.
• Existing models for certain defects like P(b1) require refinement.

Purpose of the Study:

• To characterize dangling bond defects at Si-SiO2 interfaces.
• To identify the atomic structure of the P(b1) defect.
• To validate theoretical models against experimental data.

Main Methods:

• First-principles calculations were employed.
• Hyperfine parameters were calculated for various relaxed interface structures.
• Comparison of calculated and experimental hyperfine parameters guided defect identification.

Main Results:

• Models with defect Si atoms near substrate sites successfully described P(b) and P(b0) defects.
• Models for P(b1) involving oxygen neighbors or strained bonds were ruled out.
• A novel asymmetrically oxidized dimer model showed excellent agreement with experimental hyperfine parameters.

Conclusions:

• The asymmetrically oxidized dimer is proposed as the structure of the P(b1) center.
• First-principles calculations are effective for characterizing interface defects.
• This work provides a more accurate understanding of Si-SiO2 interface defects.