TOKYO -- Semiconductor materials maker Resonac Holdings has become the first company in Japan to develop a 300-mm silicon carbide (SiC) substrate, a product that can produce quadruple the amount of integrated circuits compared with current substrates.

Resonac successfully processed a 300-millimeter -- or 12-inch -- single-crystal SiC substrate, which can yield four times as many chips as the current mainstream 150-mm substrates that are now widely used. If the larger substrates become mainstream, they could improve the energy efficiency of power semiconductors and significantly lower mass production costs.

"Maintaining uniform thickness at this size isn't easy," a representative of a Chinese semiconductor equipment maker said Monday after visiting Resonac's exhibition booth at ICSCRM 2026, a major international SiC conference held in Yokohama.

Substrates are crystalline plates that serve as the base for semiconductor production. They form the core of SiC epitaxial wafers for power semiconductor makers. Resonac produces mainly 150-mm substrates and supplies them to auto parts makers as well as semiconductor device manufacturers such as Rohm that produce wafers in-house. Resonac holds the world's largest share of external sales, beating out U.S.-based Wolfspeed.

Growing global demand for data centers is fueling expectations for SiC wafers, which offer better power efficiency and lower heat-related energy loss compared to conventional silicon wafers. The global market for power semiconductor wafers is projected to roughly triple by 2035 from 2025 levels, according to research firm Fuji Keizai, with SiC wafers accounting for just under 70% of the market.

The challenge is increasing wafer diameter. While 300-mm wafers account for 70% of the silicon wafer market by area and are mainstream in semiconductor manufacturing, SiC substrates of that size have not been commercialized.

One reason is that temperatures exceed 2,000 C during the crystal growth process essential to SiC epitaxial wafer production, making the material prone to defects. The ingots used to make epitaxial wafers are also extremely hard, requiring advanced technology to cut and polish them to become even and flat.

Resonac was formed in January 2023 through the integration of Showa Denko and Showa Denko Materials, formerly Hitachi Chemical. Showa Denko entered the SiC epitaxial wafer market in 2009 and has gradually increased wafer diameter from 76.2 mm, or three inches.

"Through the development and mass production of conventional SiC substrates, we've accumulated the processing expertise for larger diameters," said Hiromasa Suo of Resonac's device solutions unit, which develops semiconductor materials technology. "That includes precise temperature control during recrystallization and techniques for suppressing stress [that can cause substrates to warp or crack]." U.S. and Chinese companies are leading in developing 300-mm SiC substrates. China's SICC developed what it said was the industry's first SiC substrate of that size in November 2024, while Wolfspeed succeeded in producing a single-crystal substrate in January this year.

But no company has yet embarked on full-scale commercialization. Power semiconductor manufacturers would need to make substantial investments in equipment, while achieving cost benefits would require a supply system capable of consistently mass-producing substrates with few defects.

For now, Resonac plans to strengthen production capacity for 200-mm substrates, which are gradually replacing 150-mm products, while assessing the prospects for 300-mm substrates based on customer demand. "The positions of the players [in the 300-mm market] haven't been established yet," said Resonac CEO Hidehito Takahashi. "If customers need them and we can expect a first-mover advantage, we'll consider investing in it." Semiconductor and electronic materials accounted for more than 90% of Resonac's 88.8 billion yen ($564 million) in core operating profit for the January-June period of 2026. The company's main earnings drivers are materials used in the back-end stage of semiconductor manufacturing, including encapsulation and heat-dissipating materials.

If Resonac can increase its presence not only in high-purity gases and high-performance polishing materials used in front-end circuit formation, but also in wafer manufacturing technology at the beginning of the front-end process, "it would have a significant ripple effect because the company could solve customers' technological challenges across a broad range of processes," a Japanese analyst said.

An individual in the domestic industry expressed optimism, saying, "Japan has fallen behind overseas competitors because of a lack of systematization in semiconductors, but 300-mm SiC substrates could become a decisive technology for a comeback."