Conclusion of Letter of Intent with Honda R&D Co., Ltd. for Joint Research on Materials for Diamond Devices

1. Introduction

The development of various diamond devices is accelerating, and the realization of power devices for use in electric vehicles is eagerly awaited to solve the problems of existing devices and achieve widespread use. Honda R&D Co., Ltd. (hereinafter referred to as 'Honda R&D') is already advancing this development. In March 2025, in collaboration with the National Institute of Advanced Industrial Science and Technology (AIST), they published a paper demonstrating the potential of high-current devices, and in February 2026, they established the 'Honda R&D-AIST Diamond × Electronics Collaborative Research Lab' as an open innovation hub for diamond semiconductors.

Our company has long supported this development by commercializing various diamond substrates and wafers for device development. In February 2025, we commercialized the world's largest 30x30mm single crystal, and in April of the same year, we began selling 1-inch wafers (25mm in diameter). As various research institutions tackle this, the structures of the diamond devices being developed have diversified, and we have also commercialized products such as low-resistance substrates and substrates with various epitaxial layers. As a result, our company has commercialized the world's largest number of products for diamond device development.

In light of this situation, our company and Honda R&D have agreed to begin discussions towards implementing joint research to accelerate the development and practical application of diamond power devices.

2. Key Points of the Basic Agreement

Diamond devices, when applied to power devices in future electric vehicles, are expected to improve fuel efficiency through enhanced basic performance and do not present the resource issues seen with materials like gallium nitride. However, there are currently many challenges to using diamond as a semiconductor device. Additionally, using a new semiconductor material in automobiles requires a long development period for long-term durability testing. Furthermore, it is desirable to use established device manufacturing processes for automotive semiconductor production, which means that unless the development of diamond materials comes first, the device development itself cannot proceed smoothly.

The Letter of Intent signed this time is for the purpose of exploring a joint research agreement with the main themes of increasing the size and quality of diamond wafers, so that future device development can proceed with mass production in mind.

Solving these issues will enable the mass production of devices using existing semiconductor processes. By advancing this joint research, the vision for mass production will become clearer, and the path for subsequent device development will be defined. As a result, we expect to be able to formulate a concrete development plan for the practical application of power devices in automobiles, moving development into a new phase.

3. Future Steps Based on This Agreement

In accordance with this agreement, we aim to conclude a formal joint research contract with Honda R&D by the end of August 2026. After the contract is signed, development will begin using our existing facilities, and we plan to sequentially introduce necessary new equipment and construct facilities for experiments.

4. Our Company's Future Plans

In the diamond wafer development roadmap our company announced on November 28, 2024, we outlined a plan to expand wafer sizes from 2 inches to 4 inches. The development of 2-inch wafers is still proceeding diligently, and our policy to work towards realizing these products remains unchanged. We also plan to widely sell the various products that can be commercialized through this joint research to promote the adoption of diamond devices.

As a supplier of the various diamonds required for diamond device development, our company will continue to lead development globally, promote standardization for each product, and play a role in the early practical application of diamond devices.

■ For inquiries regarding this matter:

EDP Corporation, Sales Department

4-6-3 Kaminitta, Toyonaka, Osaka 560-0085

(Email) edp.info@d-edp.jp

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