Study of the process-structure-property correlation in CVD-SiC coatings on graphite substrates

Area of Science:

• Materials Science
• Chemical Engineering
• Semiconductor Manufacturing

Background:

• Graphite susceptors are vital for III-V semiconductor epitaxy (e.g., GaN/SiC).
• Silicon carbide (SiC) coatings enhance susceptor performance and stability.
• Understanding CVD SiC growth on graphite is key for advanced semiconductor fabrication.

Purpose of the Study:

• To investigate the chemical vapor deposition (CVD) of SiC coatings on graphite susceptors.
• To systematically examine the effects of temperature, pressure, and precursor ratios on SiC coating properties.
• To establish practical guidelines for producing semiconductor-grade graphite susceptors.

Main Methods:

• Chemical Vapor Deposition (CVD) using CH₃SiCl₃-H₂ precursor.
• Systematic variation of temperature (1100-1350 °C), pressure (40-150 mbar), and H₂/MTS ratio (6-12).
• Advanced characterization (XRD, SEM, XPS, nanoindentation) and Computational Fluid Dynamics (CFD) simulations.

Main Results:

• Identified kinetic regime transition at 1180 °C.
• Observed pressure-dependent surface roughness evolution (Ra: 0.8-2.1 μm).
• Achieved stoichiometric Si/C ratio of 1 with H₂/MTS ratio of 10.
• Maximized hardness (42.12 GPa) for 3C-SiC.
• Demonstrated exceptional stability during MOCVD GaN growth (Ra: 1.55 μm, no interfacial degradation).

Conclusions:

• Optimized CVD parameters yield high-quality SiC coatings on graphite susceptors.
• The developed SiC coatings are stable and suitable for demanding semiconductor epitaxy processes.
• This research provides fundamental insights and practical guidelines for semiconductor-grade susceptor production.