Are diamonds GaN’s best friend? Revolutionizing transistor technology

A research team at Osaka Metropolitan University has fabricated a gallium nitride (GaN) transistor using diamond, which of all natural materials has the highest thermal conductivity on earth, as a substrate, and they succeeded in increasing heat dissipation by more than two times compared with conventional transistors. The transistor is expected to be useful not only in the fields of 5G communication base stations, weather radar, and satellite communications, but also in microwave heating and plasma processing.

Gallium nitride (GaN) transistor on a diamond substrate: The integration of a 3C-SiC layer between GaN and diamond significantly reduces thermal resistance at the interface and improves heat dissipation, allowing for better performance.

Researchers at Osaka Metropolitan University are proving that diamonds are so much more than just a girl’s best friend. Their groundbreaking research focuses on gallium nitride (GaN) transistors, which are high-power, high-frequency semiconductor devices used in mobile data and satellite communication systems. With the increasing miniaturization of semiconductor devices, problems arise such as increases in power density and heat generation that can affect the performance, reliability, and lifetime of these devices. Therefore, effective thermal management is crucial. Diamond, which has the highest thermal conductivity of all natural materials, is an ideal substrate material but has not yet been put to practical use due to the difficulties of bonding diamond to GaN elements.

A research team led by Associate Professor Jianbo Liang and Professor Naoteru Shigekawa of the Graduate School of Engineering at Osaka Metropolitan University has successfully fabricated GaN High Electron Mobility Transistors using diamond as a substrate. This novel technology has more than twice the heat dissipation performance of transistors of the same shape fabricated on a silicon carbide (SiC) substrate. To maximize the high thermal conductivity of diamond, the researchers integrated a 3C-SiC layer, a cubic polytype of silicon carbide, between GaN and diamond. This technique significantly reduces the thermal resistance of the interface and improves heat dissipation.

“This new technology has the potential to significantly reduce CO2 emissions and potentially revolutionize the development of power and radio frequency electronics with improved thermal management capabilities,” said Professor Liang.

The results of this research were published in Small.



About OMU 
Osaka Metropolitan University is the third largest public university in Japan, formed by a merger between Osaka City University and Osaka Prefecture University in 2022. OMU upholds "Convergence of Knowledge" through 11 undergraduate schools, a college, and 15 graduate schools. For more research news visit or follow us on Twitter: @OsakaMetUniv_en, or Facebook

Published: 21 Dec 2023

Contact details:

Rina Matsuki

3-3-138 Sugimoto, Sumiyoshi-ku,
Osaka 558-8585 JAPAN

Content type: 

Title: High Thermal Stability and Low Thermal Resistance of Large Area GaN/3C-SiC/Diamond Junctions for Practical Device Processes
DOI: 10.1002/smll.202305574
Author: Ryo Kagawa, Zhe Cheng, Keisuke Kawamura, Yutaka Ohno, Chiharu Moriyama, Yoshiki Sakaida, Sumito Ouchi, Hiroki Uratani, Koji Inoue, Yasuyoshi Nagai, Naoteru Shigekawa, and Jianbo Liang
Published: November 14, 2023

Funding information:

This work was based on results obtained from a project, JPNP20004, subsidized by the New Energy and Industrial Technology Development Organization (NEDO). The TEM samples were fabricated at The Oarai Center and the Laboratory of Alpha-Ray Emitters in IMR under the Inter-University Cooperative Research in IMR of Tohoku University (202112-IRKMA-0016). The observation of the TEM samples was supported by Kyoto University Nano Technology Hub in the “Nanotechnology Platform Project” sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan (JPMXP09A21KT0006). This study was also financially supported by The Fundamental Research Funds for the Central Universities, Peking University.