High thermal conductivity of cubic silicon carbide finally demonstrated

High thermal conductivity of cubic silicon carbide finally demonstrated
by Staff Writers
Osaka, Japan (SPX) Feb 15, 2023

Semiconductors are a key component in smartphones, televisions, and other devices used in daily life using these devices generates heat, resulting in performance degradation and a shorter product life due to the rise in temperature. Therefore, there is a demand for new materials with high thermal conductivity.

Silicon carbide (SiC) is attracting significant attention as a semiconductor material for next-generation power electronics. Generally, the simpler the crystal structure, the higher the thermal conductivity. However, the thermal conductivity of 3C-SiC had not been demonstrated at theoretical levels despite having the second simplest crystal structure after diamond.

A research group, led by Associate Professor Jianbo Liang and Professor Naoteru Shigekawa from the Osaka Metropolitan University Graduate School of Engineering, has proven for the first time that 3C-SiC exhibits high thermal conductivity, equivalent to the theoretical level, based on their thermal conductivity evaluation and atomic-level analysis.

The research group used 3C-SiC crystals developed by Air Water Inc. First, they demonstrated that 3C-SiC crystals exhibit high thermal conductivity among large-diameter materials, where they were second only to diamond. Then, they showed that a thin film of 3C-SiC crystals-one-fiftieth the thickness of a hair-could exhibit a thermal conductivity higher than that of diamond, which also corresponded to the theoretical value.

Next, they performed an atomic-level analysis to investigate why they were able to measure the high thermal conductivity, which had not been previously observed. They found that the 3C-SiC crystal contained almost no impurities: the atoms in the crystal were regularly arranged, indicating a very high-quality single crystal.

Furthermore, they formed 3C-SiC crystals on a silicon substrate and performed an atomic-level analysis of the thermal conductivity of the interface, which revealed no significant disorder in the atomic arrangement at the interface and exhibited a high thermal conductance.

"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," concluded Professor Liang.

Research Report:High Thermal Conductivity in Wafer-Scale Cubic Silicon Carbide Crystals