Thermal Expansion of 3C-SiC Obtained from In-Situ X-ray Diffraction at High Temperature and First-Principal...

Area of Science:

• Materials Science
• Solid State Physics
• Crystallography

Background:

• Beta silicon carbide (3C-SiC) is a critical semiconductor material.
• Understanding its thermal expansion is vital for high-temperature applications.
• Accurate thermal expansion data is needed for material design and performance prediction.

Purpose of the Study:

• To experimentally determine the coefficient of thermal expansion (CTE) of 3C-SiC.
• To computationally validate the CTE using density functional theory.
• To establish a comprehensive understanding of 3C-SiC's thermal behavior.

Main Methods:

• In situ X-ray crystallography powder diffraction was used to study 3C-SiC from 25-800 °C.
• CASTEP codes and density functional theory calculated phonon frequencies at various pressures.
• The Gruneisen formalism was applied for computational CTE determination.

Main Results:

• At 25 °C, the lattice parameter of 3C-SiC was 4.596 Å, with a CTE of 2.4 ×10⁻⁶/°C.
• The experimental CTE followed a second-order polynomial relationship with temperature.
• Computational methods yielded a CTE of 2.2 ×10⁻⁶/°C, consistent with experimental findings.

Conclusions:

• This research presents a novel two-step approach to determine 3C-SiC's thermal expansion.
• Both experimental and computational results provide reliable data for material scientists.
• The findings enhance the understanding of 3C-SiC's behavior under thermal stress.