Shin-Etsu Chemical recognizes the critical role of its QST® (Qromis Substrate Technology) substrate in facilitating the widespread adoption of high-performance, energy-efficient GaN (gallium nitride) power devices. The company is determined to drive the development and commercialization of these products.
One of the key advantages of the QST® substrate is its ability to match the coefficient of thermal expansion (CTE) of GaN. This characteristic mitigates warpage and cracking issues in the GaN epitaxial layer, enabling the creation of thick, large-diameter GaN epitaxial layers of superior quality. Leveraging these properties, QST® substrate is expected to find applications in power devices, RF devices (including 5G and beyond 5G), and the growth of MicroLEDs for MicroLED displays, all of which have witnessed significant advancements in recent years.
Apart from producing QST® substrates, Shin-Etsu Chemical will also offer GaN-grown QST® substrates upon customer request. Currently, the company holds stocks of substrates with 6" and 8" diameters, with the development of 12" substrates underway. Since 2021, there has been ongoing sample evaluation and device development for various applications, such as power devices, RF devices, and LEDs, in collaboration with numerous Japanese and international clients. Notably, the assessment of devices spanning the 650V to 1800V range is presently ongoing.
Over the years, Shin-Etsu Chemical has continually improved its QST® substrates. Through significant advancements in reducing bonding process-related defects, the company has achieved a steady supply of high-quality QST® substrates. Additionally, by offering template substrates with optimized buffer layers, Shin-Etsu Chemical has facilitated the request for thicker GaN films from its clients, ensuring sustained epitaxial growth of greater than 10 μm thickness. The company has also achieved significant milestones, including the successful growth of thick-film GaN exceeding 20 μm on QST® substrates and the realization of a 1800V breakdown voltage in power devices.
In collaboration with Oki Electric Industry Co., Ltd., Shin-Etsu Chemical has achieved a breakthrough in exfoliating GaN from QST® substrates and transferring it to substrates made of various materials using Crystal Film Bonding (CFB) technology. Leveraging the properties of QST® substrates, this innovation enables the creation of vertical power devices capable of handling large currents. The exfoliation process involves removing a thick layer of high-quality GaN from an insulating QST® substrate.
Shin-Etsu Chemical will provide QST® substrates or GaN-grown QST® substrates to customers manufacturing GaN devices, while Oki Electric Industry will offer its CFB technology through partnerships or licensing arrangements. Both companies believe that this collaboration will significantly contribute to the advancement of vertical power devices. Shin-Etsu Chemical is committed to increasing production to meet the rising customer demand resulting from these developments and the numerous inquiries received regarding business situations.
