High thermal conductivity electronic materials are critical components for high-performance electronic and photonic devices as active functional and thermal management materials.
Silicon carbide (SiC) is receiving a lot of attention as a semiconductor material for next-generation power electronics. In general, heat conductivity increases with crystal structural simplicity. Despite having the second-simplest crystal structure after diamond, 3C-SiC’s thermal conductivity had not been experimentally proven.
Based on their thermal conductivity evaluation and atomic-level analysis, a research team led by Associate Professor Jianbo Liang and Professor Naoteru Shigekawa from the Osaka Metropolitan University Graduate School of Engineering has for the first time demonstrated that 3C-SiC exhibits high thermal conductivity, equivalent to the theoretical level.
The study team used 3C-SiC crystals produced by Air Water Inc. First, they showed that 3C-SiC crystals have thermal solid conductivity, second only to diamond among materials with large diameters. Then, they demonstrated that a thin film of 3C-SiC crystals, which was only one-fiftieth the thickness of a hair, could exhibit thermal conductivity higher than a diamond and matched the theoretical value.
The reason they were able to measure the high thermal conductivity, which had not previously been seen, was then investigated using an atomic-level study. They discovered that the 3C-SiC crystal had nearly no impurities since it had evenly spaced atoms, a sign of a very high-quality single crystal.
They also created 3C-SiC crystals on a silicon substrate. They examined the thermal conductivity of the interface at the atomic level, which found no discernible disorder in the atomic arrangement and demonstrated high thermal conductance.
Associate Professor Jianbo Liang from the Osaka Metropolitan University Graduate School of Engineering said, “Both the freestanding 3C-SiC crystal and thin films on a silicon substrate have high thermal conductivity, and we expect large-diameter wafers can be fabricated at a low cost. This should lead to improved heat dissipation on a practical level in electronic devices.”
Journal Reference:
- Cheng, Z., Liang, J., Kawamura, K., et al. High thermal conductivity in wafer-scale cubic silicon carbide crystals. Nat Commun 13, 7201 (2022). DOI: 10.1038/s41467-022-34943-w