In a monumental leap for next-generation telecommunications and space technology, a research group led by Saga University, in collaboration with the Japan Aerospace Exploration Agency (JAXA) and Diamond Semiconductor Inc., has successfully developed a high-frequency semiconductor device using diamond. This breakthrough promises to revolutionize how we approach microwave and millimeter-wave amplification, particularly for 6G and satellite communications.
The newly developed device utilizes diamond, often referred to as the "ultimate semiconductor material" due to its superior physical properties compared to traditional silicon or gallium nitride. The team focused on creating a device capable of operating in the microwave band (three to thirty gigahertz) and the millimeter-wave band (thirty to three hundred gigahertz).
One of the most striking achievements of this project is the record-breaking performance metrics. The device demonstrated an off-state breakdown voltage of four thousand two hundred sixty-six volts. Furthermore, the cut-off frequency for power gain reached one hundred twenty gigahertz. According to the research team, both of these figures represent the world's highest level of performance for diamond-based devices.
To achieve this, the team employed advanced processing techniques, including the creation of a T-shaped gate electrode with a width of just one hundred fifty-seven nanometers using electron beam lithography. They also significantly improved the purity of the aluminum oxide used in the gate insulation layer, which was crucial for boosting the breakdown voltage.
Currently, satellite communication systems rely heavily on vacuum tubes, such as traveling wave tubes, for high-frequency amplification. However, these are bulky and have shorter lifespans. This new diamond semiconductor device offers a solid-state alternative that is compact, highly efficient, and radiation-resistant, making it ideal for the harsh environment of space and the demanding requirements of future 6G base stations.
The research group plans to continue optimizing the device for practical deployment, with Diamond Semiconductor Inc. aiming to begin sample sales soon. This development marks a significant step toward replacing legacy vacuum tube technology with robust, high-performance solid-state diamond devices.
