The National Institute of Advanced Industrial Science and Technology (AIST) in Japan, in collaboration with Honda R&D, has fabricated a prototype of a p-type diamond MOSFET and demonstrated ampere-level high-speed switching operation for the first time. In the future, the company plans to incorporate this technology into the next generation of mobile power devices and conduct operational verification in the hope of implementing it in society.

In March 2025, Hitoshi Umezawa, senior chief researcher of the New Functional Device Team of the Advanced Power Electronics Research Center of the National Institute of Advanced Industrial Science and Technology (AIST), Toshiharu Makino, head of the research team, and Daisuke Takeuchi, deputy director of the research center, announced that they had collaborated with Honda Research Institute to trial-produce p-type diamond MOSFETs and demonstrated high-speed switching operations at the ampere level for the first time. In the future, the company plans to carry this technology in the next generation of mobile power devices and conduct operational verification in the hope of implementing it in society.

Diamond semiconductors

Diamond semiconductors are called the ultimate semiconductors and have excellent properties, including the ability to achieve high energy efficiency. Therefore, it is expected to be used in a variety of fields such as electric vehicles and renewable energy. However, the use of diamond as a semiconductor material also brings many challenges, such as difficulties in crystal growth and processing. In addition, in order to be put into practical use, it is necessary to be able to handle large currents at the ampere level and perform high-speed switching operations.

To increase the current, the research team used a larger substrate size than conventional methods and developed a wiring technology that enables parallel operation. Specifically, a large number of p-type power MOSFETs were fabricated on a half-inch single-crystal diamond substrate using a two-dimensional hole carrier gas terminated with hydrogen, and wiring was performed to achieve parallel operation.

The characteristics of the prepared diamond MOSFET were evaluated. It was confirmed that a single element with a gate width of 1020μm had excellent operating characteristics, and that elements could be manufactured on the same substrate with a high yield.

In addition, the source, gate, and drain electrodes of 314 single elements were connected in parallel. The gate connection method made the total gate width about 32cm, and the switching speed of the element was evaluated using the double pulse method. The results confirmed that when the drive current was 2.5A, the fall time was 19 nanoseconds and the rise time was 32 nanoseconds.

Reference link: https://eetimes.itmedia.co.jp/ee/articles/2503/26/news097.html

Source: Content compiled from eetjp

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