Epitaxial silicon oxynitride layer on a 6H-SiC(0001) surface

Area of Science:

• Materials Science
• Surface Science
• Semiconductor Physics

Background:

• Silicon carbide (SiC) is a crucial semiconductor material for high-power and high-frequency devices.
• Developing stable and high-quality epitaxial layers on SiC is essential for advanced device fabrication.
• Existing surface treatments often result in defects or instability.

Purpose of the Study:

• To synthesize and characterize a novel silicon oxynitride (SiON) epitaxial layer on a 6H-SiC(0001) surface.
• To elucidate the atomic structure and electronic properties of the newly formed SiON layer.
• To assess the potential of this epitaxial layer for future device applications.

Main Methods:

• Hydrogen-gas etching of 6H-SiC(0001) followed by annealing in a nitrogen atmosphere.
• Quantitative low-energy electron diffraction (LEED) for structural analysis.
• Scanning tunneling spectroscopy (STS) for electronic property measurements.

Main Results:

• Formation of a stable silicon oxynitride (SiON) epitaxial layer.
• Determination of a hetero-double-layer structure: silicate monolayer on silicon nitride monolayer with Si-O-Si bonds.
• Absence of dangling bonds, ensuring robustness against air exposure.
• Observation of a bulk SiO2-like band gap of approximately 9 eV via STS.

Conclusions:

• A novel, robust SiON epitaxial layer with a unique hetero-double-layer structure has been successfully synthesized on 6H-SiC.
• The absence of dangling bonds and the observed band gap indicate significant potential for electronic device applications.
• This material represents a promising advancement in SiC surface engineering and semiconductor technology.