IMEC has selected Shin-Etsu Chemical’s QST substrate—a 300-mm platform designed for GaN growth—for use in its 300-mm GaN power device development program, where testing and evaluation are now in progress.
Initial findings have been very encouraging. A 5-micron-thick GaN HEMT device produced on the QST substrate has achieved a record voltage result, surpassing 650 V on a full 300-mm wafer.
Shin-Etsu Chemical currently manufactures QST substrates in 150-mm and 200-mm formats, along with GaN-on-QST epitaxial substrates in multiple sizes, under license from QROMIS.
In September 2024, Shin-Etsu began delivering 300-mm QST sample substrates as part of a joint effort with QROMIS. This collaboration has since grown into a close partnership supporting IMEC’s advanced 300-mm CMOS manufacturing facility in Leuven, Belgium.
IMEC formally initiated its 300-mm GaN power device development program in October 2025, outlining its strategy to build GaN devices on 300-mm QST substrates. The effort is aimed at key markets such as AI data centers, industrial equipment, and automotive electronics, starting with a 650-V class device and later expanding to designs rated above 1,200 V.
During the initial evaluation stage, IMEC successfully produced a 5-micron-thick high-voltage GaN HEMT structure on Shin-Etsu Chemical’s 300-mm QST substrate using Aixtron’s Hyperion MOCVD platform, in full compliance with SEMI manufacturing standards. The resulting device achieved a record-breaking breakdown voltage exceeding 800 V and showed excellent uniformity across the wafer. These outcomes underscore the benefits of QST substrates, whose thermal expansion closely aligns with GaN, allowing stable, high-quality crystal growth even at large wafer sizes.
Although moving to larger wafers is critical for lowering costs by using established silicon manufacturing infrastructure, GaN-on-silicon solutions face significant challenges at 300 mm, including wafer bowing and cracking that reduce yield. The 300-mm QST substrate addresses these issues by supporting thick GaN layers without structural defects, enabling a realistic path toward high-volume production of high-voltage devices.
Shin-Etsu Chemical is progressing toward full-scale manufacturing of 300-mm QST substrates, which are already under evaluation by customers worldwide for power, RF, and LED applications—driven in particular by rising demand from AI data center power systems.
