Mechanism of Tailoring Laser-Induced Periodic Surface Structures on 4H-SiC Crystal Using Ultrashort-Pulse Laser

Area of Science:

• Materials Science
• Laser Physics
• Surface Engineering

Background:

• Laser-induced periodic surface structures (LIPSSs) are crucial for modifying material surfaces.
• Understanding LIPSS formation mechanisms on different semiconductor substrates is essential for advanced applications.
• Silicon carbide (SiC) is a key material in high-power electronics and optoelectronics.

Purpose of the Study:

• To investigate LIPSS characteristics on N-doped 4H-SiC (N-SiC) and high-purity 4H-SiC (HP-SiC) using femtosecond-picosecond lasers.
• To systematically analyze the influence of laser parameters on LIPSS orientation, size, and morphology.
• To elucidate the physical mechanisms behind varied LIPSS formation on distinct SiC crystal types.

Main Methods:

• Fabrication of LIPSS on N-SiC and HP-SiC using femtosecond-picosecond laser irradiation.
• Systematic variation of laser parameters (e.g., pulse number, fluence) to study their effects.
• Analysis of LIPSS morphology, size, and orientation using microscopy and related techniques.
• Investigation of photothermal absorption and electric field modulation differences.

Main Results:

• LIPSS area on both N-SiC and HP-SiC increased linearly with the number of laser pulses under identical conditions.
• N-SiC exhibited a higher LIPSS growth coefficient compared to HP-SiC.
• Distinct SiC crystal properties (photothermal absorption, electric field modulation) led to varied LIPSS formation outcomes.

Conclusions:

• The study clarifies the physical mechanisms governing LIPSS formation on N-SiC and HP-SiC.
• Findings provide guidance for controlling LIPSS size and orientation on different 4H-SiC substrates.
• This research contributes to the precise engineering of SiC surfaces for advanced material applications.