Multidimensional defect identification of semiconductors in nonequilibrium

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Static theory for semiconductor defects is insufficient for nonequilibrium conditions like irradiation.
• Identifying deep-level defects under irradiation presents significant challenges.

Purpose of the Study:

• To develop a robust ab initio-driven multiscale modeling framework for identifying deep-level defects in irradiated semiconductors.
• To overcome challenges in unambiguous nonequilibrium defect identification and accurate deep-level transient spectroscopy (DLTS) simulation.

Main Methods:

• Developed a multiscale modeling framework integrating ab initio calculations.
• Simulated DLTS to identify defect properties.
• Applied the framework to neutron-irradiated silicon (Si) and 4H-silicon carbide (4H-SiC).

Main Results:

• Successfully identified known deep-level defects in neutron-irradiated Si.
• Resolved the atomic origin of controversial deep levels in neutron-irradiated 4H-SiC.
• Discovered that defect origins vary with annealing temperature, challenging static defect theory.

Conclusions:

• The developed framework accurately identifies deep-level defects in irradiated semiconductors under nonequilibrium conditions.
• The findings provide new insights into semiconductor defect physics, particularly the dynamic behavior of defects.
• This work lays the foundation for controlling crucial defects to enhance material properties and device performance.