Ookuma DIAMOND Device Co., Ltd.
CEO

Mr. Hoshikawa Naohisa

During his studies at the Accounting Graduate School of Hokkaido University, he founded a company that achieved six consecutive years of profitability before being successfully exited. He has been involved in diamond semiconductor research since 2016 and established the present company in 2022. With expertise spanning both management and technology, he has secured more than 2 billion yen in competitive research funding. He was the first student to receive a business loan from Hokkaido Bank and was selected for Forbes Japan’s 2025 list of notable entrepreneurs.

Diamond semiconductors have been explored for more than three decades as an ultimate semiconductor material, but practical adoption did not progress because silicon met industrial demands at the time. A turning point came with the decommissioning of the Fukushima Daiichi nuclear plant, which required operation under extreme radiation. To meet this national challenge, a government program launched in 2012, achieving prototype devices in 2021.
Beyond exceptional radiation hardness, diamond semiconductors offer high-frequency and high-power performance, superior thermal conductivity, and outstanding heat tolerance-features that overcome the self-heating limits of conventional devices. They are expected to drive major advances in space, national security, next-generation communications, and data-center technologies, emerging as a core platform for electronics in extreme environments.