Relation between work function and structural properties of triangular defects in 4H-SiC epitaxial layer: Kelvin...

Area of Science:

• Materials Science
• Semiconductor Physics

Background:

• 4H-SiC is a crucial semiconductor material.
• Understanding defects in SiC epitaxial layers is vital for device performance.
• Triangular defects can impact electronic and mechanical properties.

Purpose of the Study:

• To investigate the relationship between work function and structural properties of triangular defects in 4H-SiC.
• To characterize the polytype, stress, and carrier generation within these defects.
• To analyze the mechanical integrity of the defects.

Main Methods:

• Kelvin probe force microscopy (KPFM) for surface potential mapping.
• Spectroscopic analyses including micro-Raman and photoluminescence (PL).
• Nanoindentation for mechanical property evaluation.

Main Results:

• Triangular defects are predominantly 3C polytypes with internal stress and defects.
• Defects exhibit distinct surface potential differences compared to the 4H-SiC matrix due to work function variations.
• Mechanical properties are significantly deteriorated by dislocations and stacking faults.

Conclusions:

• Work function variations in defects are linked to 3C polytype electron affinity and Fermi level shifts.
• Tensile stress contributes to surface disorder and altered electron affinity.
• Structural imperfections like dislocations and stacking faults severely degrade mechanical properties.