Structural Controlling of Highly-Oriented Polycrystal 3C-SiC Bulks via Halide CVD

Area of Science:

• Materials Science
• Chemical Engineering
• Crystallography

Background:

• Highly-oriented polycrystalline 3C-SiC (Silicon Carbide) is crucial for advanced applications.
• Controlling grain orientation and surface morphology is key to tailoring material properties.
• Understanding deposition mechanisms is essential for optimizing fabrication processes.

Purpose of the Study:

• To investigate the ultra-fast fabrication of highly-oriented 3C-SiC bulks using halide chemical vapor deposition (CVD).
• To determine the influence of deposition temperature (T_dep) and total pressure (P_tot) on 3C-SiC grain orientation and surface morphology.
• To examine the wetting behavior of fabricated CVD-SiC by molten aluminum.

Main Methods:

• Fabrication of 3C-SiC bulks via halide chemical vapor deposition (CVD) using tetrachlorosilane (SiCl₄) and methane (CH₄).
• Systematic variation of deposition temperature (T_dep) and total pressure (P_tot).
• Analysis of grain orientation using crystallographic methods.
• Characterization of surface morphology using microscopy.
• Wetting behavior examination of CVD-SiC by molten aluminum at 1173 K in a high vacuum.

Main Results:

• Growth orientation of 3C-SiC columnar grains was strongly dependent on T_dep, transitioning from <111>- to <110>-orientation with increasing temperature.
• The arrangement of <111>-oriented columnar grains was effectively controlled by P_tot.
• Unique surface morphologies, including lotus-, turtle-, thorn-, and strawberry-like structures, were observed, correlating with grain arrangements.
• Wetting behavior of CVD-SiC by molten aluminum was successfully examined.

Conclusions:

• Ultra-fast fabrication of highly-oriented 3C-SiC bulks is achievable via halide CVD.
• Deposition temperature and pressure are critical parameters for controlling 3C-SiC crystal growth orientation and surface morphology.
• The observed surface morphologies are a direct consequence of the arrangement of oriented grains, providing insights into the deposition mechanism.