Shin-Etsu Chemical to develop QST substrate for 300mm GaN

News: Suppliers Tokyo-based Shin-Etsu Chemical Co Ltd has created a 300mm (12-inch) QST substrate, and recently started supplying samples. Developed by Qromis Inc of Santa Clara, CA, USA, QST (Qromis Substrate Technology) is dedicated to GaN epitaxial growth and was licensed to Shin-Etsu Chemical in 2019. Shin-Etsu Chemical has since sold 150mm (6-inch) and 200mm (8-inch) QST substrates and GaN-on-QST epitaxial substrates of each diameter. Meanwhile, in response to customer demand, the firm worked on further increasing the diameter and developed a 300mm (12-inch) QST substrate. GaN device manufacturers cannot benefit from increasing the diameter of materials because of the lack of a large-diameter substrate suitable for GaN growth, despite the fact that they can use existing silicon production lines for GaN, notes Shin-Etsu Chemical. The new 300mm QST substrate is said to enable GaN epitaxial growth without warping or cracks (which was unattainable on silicon substrates), significantly reducing device costs. In addition to the enhancement of facilities for 150mm and 200mm QST substrates already in progress, Shin-Etsu Chemical is working on mass-producing 300mm QST substrates. Since QST substrates have the same coefficient of thermal expansion as that of GaN, it is possible to constrain warping and cracks of GaN epitaxial layer on QST substrate of the SEMI standard thickness. This substrate material allows for high-quality and thick GaN epitaxial growth with a large diameter. Leveraging this feature, many customers are evaluating QST substrates and GaN-on-QST epitaxial substrates for power devices, high-frequency devices, and LEDs, says Shin-Etsu Chemical. Despite the challenging business environment, customers have entered the development phase to address the recently increasing interest in power devices, including power supplies for data centers. The addition of the 300mm QST substrate to the 150mm and 200mm lineup can significantly accelerate the spread of GaN devices, reckons the firm. Shin-Etsu Chemical exhibited the 300mm QST substrate at SEMICON TAIWAN 2024 in Taipei, Taiwan (4–6 September).OKI develops GaN lifting-off/bonding technology on Shin-Etsu’s QST substratesShin-Etsu Chemical launches QST substrates for GaN power device growthShin-Etsu licenses Qromis’ GaN substrate technologyShin-Etsu Chemical GaN-on-Siwww.semicontaiwan.orgwww.shinetsu.co.jp