Nondestructive detection and identification of electrically active threading dislocations in n⁺-SiC substrates

Area of Science:

• Materials Science
• Semiconductor Physics
• Defect Engineering

Background:

• Threading dislocations (TDs) are prevalent defects in n+-SiC substrates.
• A subset of TDs, deep state TDs (DS-TDs), significantly impacts device performance.
• Conventional photoluminescence (PL) struggles to selectively detect electrically active DS-TDs due to PL quenching.

Purpose of the Study:

• To develop a novel method for the selective detection of electrically active dislocations in n+-SiC.
• To overcome the limitations of conventional PL techniques in defect characterization.
• To enable non-destructive, in-line inspection of critical defects in SiC.

Main Methods:

• Confocal subsurface defect photoluminescence (PL) spectro-microscopy.
• Selective photoionization of deep states within dislocations.
• 3D imaging via combined dislocation line and etch pit emissions.

Main Results:

• Successfully developed a technique to selectively detect screw-component DS-TDs (DS-STDs) in n+-SiC.
• Activated DS-STD-specific emissions by photoionizing deep states.
• Achieved high-contrast 3D imaging of partially etched DS-STDs.

Conclusions:

• The developed confocal subsurface defect-PL spectro-microscopy enables selective detection of electrically active dislocations.
• This method overcomes PL quenching limitations in highly doped SiC.
• Paves the way for non-destructive, in-line quality control of SiC substrates.