Japanese Materials Company Resonac Develops 300mm Silicon Carbide Substrates, Not to Sell Large Wafers
A development lead at Japanese materials company Resonac explained that the core objective of developing 300mm silicon carbide (SiC) single-crystal substrates is to overcome the extreme difficulties of growing large-diameter crystals and feed those insights back into improving the quality of existing 150mm and 200mm products, rather than preparing for the commercialization of 300mm wafers. The interview also revealed the real-world constraints on transitioning SiC substrates from current sizes to larger diameters: the equipment environments of device manufacturers, cost thresholds for substrates, and the scale of end-user demand.
The silicon carbide (SiC) power semiconductor industry is currently undergoing a transition from 150mm to 200mm substrates. According to a development lead at Japanese materials company Resonac, 200mm products are expected to become mainstream around 2030, with a full transition to 300mm occurring only after that. Against this backdrop, Resonac announced in September 2026 that it had successfully grown and processed a 300mm-diameter SiC single-crystal substrate, making its first public display at the International Conference on Silicon Carbide and Related Materials (ICSCRM 2026) held in Yokohama later that same month. On the surface, this appears to be preparation for next-generation mass production. However, the development lead's answer was unexpected: there are no plans to sell 300mm SiC epitaxial wafers; the purpose of the development is purely to enhance the competitiveness of existing 150mm and 200mm products.
This logic rests on a specific materials science fact. During SiC single-crystal growth, the larger the diameter, the more difficult it becomes to control conditions such as temperature distribution during crystallization. Resonac's strategy is to proactively tackle these control challenges by attempting the most difficult condition—the 300mm size—and then feeding back the resulting expertise, such as thermal field design, into smaller-diameter products already in mass production. In other words, the 300mm substrate here is not a product itself, but a yardstick—a tool used to calibrate the company's process limits at more practical, smaller sizes.