Electronic materials with high thermal conductivity are critical components for high performance electronic and photonic devices as active functional and thermal management materials.

Silicon carbide (SiC) is gaining a lot of attention as a semiconductor material for next generation power electronics. In general, the thermal conductivity increases with the simplicity of the crystal structure. Despite having the second simplest crystal structure after diamond, the thermal conductivity of 3C-SiC had not been experimentally proven.

Based on their thermal conductivity evaluation and analysis at the atomic level, a research team led by Associate Professor Jianbo Liang and Professor Naoteru Shigekawa of Osaka Metropolitan University Graduate School of Engineering has shown for the first time that 3C-SiC exhibits high thermal conductivity, comparable to to the theoretical level.

The research 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 large-diameter materials. They then showed that a thin film of 3C-SiC crystals, just one-fiftieth the thickness of a hair, could exhibit a thermal conductivity higher than that of a diamond, matching the theoretical value.

The reason why they were able to measure the high thermal conductivity, which had not been observed before, was then investigated using an atomic-level study. They found that the 3C-SiC crystal contained almost no impurities because 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, finding no discernible disorder in the atomic arrangement and showing high thermal conductivity.

Associate Professor Jianbo Liang of Osaka Metropolitan University Graduate School of Engineering said: “Both the free-standing 3C-SiC crystal and the thin films on a silicon substrate have high thermal conductivity, and we expect that large-diameter wafers can be fabricated at a low cost. This should lead to improved practical-level heat dissipation in electronic devices .”

Magazine reference:

  1. 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