Shin-Etsu Chemical Co., Ltd. (Headquarters: Tokyo; President: Yasuhiko Saitoh) has developed a 300-mm (12-inch) QST™ substrate specifically designed for GaN (gallium nitride) epitaxial growth and has begun supplying sample units.
Previously, Shin-Etsu Chemical offered 150-mm (6-inch) and 200-mm (8-inch) QST™ substrates, along with GaN on QST™ epitaxial substrates in these sizes. However, due to strong customer demand, the company has successfully expanded the substrate size to 300 mm (12 inches). While GaN device manufacturers could utilize existing silicon production lines, they faced challenges due to the unavailability of large-diameter substrates suitable for GaN growth. The newly developed 300-mm QST™ substrate allows for GaN epitaxial growth without the warping or cracking seen with silicon substrates, significantly reducing device costs. In addition to expanding production facilities for its 150-mm and 200-mm QST™ substrates, Shin-Etsu Chemical is preparing for mass production of the 300-mm version.
QST™ substrates share the same coefficient of thermal expansion as GaN, effectively minimizing warping and cracks in the epitaxial layer on standard-thickness SEMI substrates. This makes it possible to grow high-quality, thick GaN epitaxial layers on larger-diameter substrates. As a result, many customers are now testing QST™ substrates and GaN on QST™ epitaxial substrates for applications in power devices, high-frequency devices, and LEDs. Despite current industry challenges, customer interest in power devices, especially for data center power supplies, has led to a development phase aimed at practical applications.
With the introduction of the 300-mm QST™ substrate, Shin-Etsu Chemical aims to accelerate the adoption of GaN devices, contributing to the efficient use of energy and the realization of a sustainable society. The company plans to showcase the 300-mm QST™ substrate at SEMICON TAIWAN in Taipei from September 4 to 6, 2024.
