Diamond power semiconductors offering performance an order of magnitude beyond current materials are drawing closer to commercial viability thanks to advances originating from Japan.
Such semiconductors are made from synthetic diamond, which has been called the ultimate semiconductor material due to its thermal conductivity and other properties.
Diamond is particularly suited for use in power semiconductors because it has about 33 times as much electrical strength as an insulator as silicon. Diamond power semiconductors can also operate in environments roughly five times as hot, and theoretically have the capacity to handle approximately 50,000 times as much electricity.
Silicon carbide (SiC) and gallium nitride (GaN) have also attracted attention as next-generation semiconductor substrates, but the performance of diamond is vastly higher.
Using the Baliga figure of merit, diamond exhibits over 80 times the performance of SiC and more than 10 times the performance of GaN. A higher Baliga figure of merit score means the material is more able to significantly reduce power loss.
Diamond semiconductors are being considered for applications that require a large, stable power supply, including electric vehicles, flying cars, and power generation stations. Their resistance to high temperatures and radiation is also expected to make the semiconductors suitable for use in nuclear power and space, among other areas.
Research into diamond as a semiconductor material has been ongoing for more than three decades, but has faced many obstacles.
The hardness of diamond makes it difficult to grind and process the material with the precision needed for electronic devices. Diamond can also deteriorate when used in semiconductors for long periods of time. Trying to form larger substrates with diamonds is a particular challenge, while costs have impeded commercialization.
But following considerable progress over the past few years, diamond semiconductors are expected to enter the commercialization stage between next year and 2030. Japan is a leader in R&D in the field.
In 2023, a team at Japan’s Saga University successfully developed the world’s first power circuit incorporating diamond semiconductors. Orbray, a Tokyo-based manufacturer of precision components, has developed technology to mass produce 2-inch diamond wafers, surpassing the previous limit of 1 inch. The company expects to develop a 4-inch wafer soon.
In December, Tokyo startup Power Diamond Systems developed a diamond component capable of handling a world-leading 6.8 amperes of electrical current. The company plans to start shipping samples within a few years.
Ookuma Diamond Device, another startup in Hokkaido, is constructing a factory in Fukushima prefecture that will mass produce diamond semiconductors. The plant is due to start operations in fiscal 2026, with a goal to install semiconductors in equipment used for removing debris at the disaster-struck Fukushima Daiichi nuclear power plant.
As expectations for commercial use grow, listed companies involved in related fields are likely to attract more attention. JTEC Corporation, which manufactures precision equipment for research facilities, has a unique technology for polishing the surfaces of high-hardness materials using plasma.
It has already succeeded in polishing single crystal diamond substrates of a world-leading size efficiently and without causing damage, and has received orders for development equipment used in diamond material processing. The company aims to increase sales in its related business to JPY 700 million (USD 4.9 million) by the year ending June 2027, more than double the target for the current fiscal year.
EDP, listed on the Tokyo Stock Exchange’s Growth market, is the only company in Japan that manufactures and sells the seeds from which synthetic diamonds for jewelry are made. It has established a system to produce the world’s largest single crystals using technology developed by the National Institute of Advanced Industrial Science and Technology.
If diamond semiconductors become widespread in the future, a stable supply of high-quality synthetic diamonds will be critical. Currently, most are made in India and China.
“The production of synthetic diamonds depends on the technological capabilities of the company, not on the machines being used,” said Takuya Ito, representative director of synthetic diamond wholesaler Pure Diamond.
Ito added that each company customizes its production equipment and uses its own recipes to produce synthetic diamonds, so the quality and size vary greatly. Recently, a South Korean company developed technology to produce synthetic diamonds more rapidly.
This article first appeared on Nikkei Asia. It has been republished here as part of 36Kr’s ongoing partnership with Nikkei.
