Introduction

Gallium nitride (GaN), as a third-generation semiconductor material, possesses exceptional properties such as a wide bandgap (3.4 eV), high electron mobility, a high breakdown electric field (~3.3 MV/cm), and excellent thermal stability. These characteristics make it highly suitable for applications in RF communications, power electronics, and optoelectronics. As the semiconductor industry shifts toward larger wafer sizes, 8-inch GaN single-crystal substrates are gaining significant attention due to their superior performance and cost advantages. This article explores the benefits of 8-inch GaN single-crystal substrates from the perspectives of material properties, manufacturing efficiency, application potential, and industrial impact.

1. Superior Material Properties

Compared to conventional substrates such as Si, SiC, and sapphire, GaN single-crystal substrates exhibit higher crystalline quality, significantly reducing defect density and strain caused by lattice mismatch and differences in thermal expansion coefficients. The dislocation density of 8-inch GaN single-crystal substrates is typically below 10⁶ cm⁻², which is several orders of magnitude lower than that of GaN-on-Si and GaN-on-SiC epitaxial structures. This leads to improved device breakdown voltage, enhanced electron mobility, and greater overall reliability. Additionally, GaN substrates enable vertical device architectures, further increasing current density and thermal management efficiency, making them well-suited for high-voltage and high-temperature applications.

JXT has extensive expertise in GaN substrate technology and offers 2- to 4-inch GaN single-crystal substrates, along with GaN epitaxy on sapphire, silicon, and GaN native substrates, catering to diverse application needs. These epitaxial solutions support high-frequency RF devices, power electronics, and optoelectronic devices, expanding GaN's industrial applications.

2. Increased Manufacturing Efficiency and Cost Optimization

Wafer size expansion is crucial in the semiconductor industry. Compared to 4-inch or 6-inch GaN substrates, 8-inch GaN substrates enable higher chip yields per wafer under the same fabrication conditions, thereby reducing per-unit chip manufacturing costs. Additionally, 8-inch GaN substrates are compatible with existing 8-inch semiconductor production lines, minimizing the need for major equipment modifications and accelerating GaN technology's industrialization. This compatibility not only facilitates the adoption of GaN power and RF devices but also lays the foundation for future production of even larger GaN wafers, such as 12-inch substrates.

3. Ideal for High-Power and High-Frequency Applications

8-inch GaN single-crystal substrates provide an optimal foundation for high-power and high-frequency electronic devices. GaN-based devices demonstrate superior performance over Si and SiC in applications such as 5G/6G base station RF power amplifiers, high-power millimeter-wave communication, radar systems, electric vehicle (EV) power modules, efficient power management, and high-voltage power grids. The high electron mobility of GaN enables higher switching frequencies, significantly improving power conversion efficiency, reducing energy loss, and minimizing thermal management requirements. Moreover, GaN-based power devices offer faster switching speeds, enhancing system dynamic response, and securing a critical position in the high-frequency power electronics market.

JXT provides GaN epitaxial solutions on sapphire, silicon, and GaN native substrates, tailored to different applications. For instance, GaN-on-sapphire is widely used in optoelectronics and LEDs, GaN-on-Si offers a cost-effective solution for power electronics, while GaN-on-GaN enables the highest material quality, ideal for high-end RF and power devices.

4. Excellent Thermal Performance and Reliability

Compared to GaN-on-Si or GaN-on-SiC, GaN single-crystal substrates have superior thermal conductivity, effectively reducing thermal stress during device operation, enhancing heat dissipation, and prolonging device lifespan. With increasing wafer size, 8-inch GaN substrates offer further advantages in uniformity control, warpage suppression, and thickness optimization, contributing to better thermal stability. In high-power density applications, GaN substrates with low thermal resistance and high thermal conductivity will be a crucial factor in improving device reliability.

5. Driving GaN Industry Advancement

The successful commercialization of 8-inch GaN single-crystal substrates will accelerate the entire GaN semiconductor supply chain. As domestic and international companies continue advancing 8-inch GaN substrate production, associated technologies in GaN epitaxy, chip fabrication, and packaging & testing will also evolve rapidly, further promoting the localization of GaN power and RF devices. Additionally, as large-diameter GaN substrates become widely adopted, costs will gradually decrease, making GaN devices more affordable and expanding their application in consumer electronics, new energy vehicles, and high-speed communication systems.

As a key player in the GaN industry, JXT offers 2- to 4-inch GaN single-crystal substrates and various epitaxial solutions, supporting different types of GaN device manufacturing. Looking ahead, JXT will continue to optimize material quality and process technology, paving the way for the industrialization of 8-inch and even larger GaN substrates.

Conclusion

8-inch GaN single-crystal substrates, with their superior material properties, improved manufacturing efficiency, cost reduction, broad high-power and high-frequency application potential, and ability to advance the GaN industry, represent a crucial direction in GaN semiconductor development. Although challenges remain in terms of defect density control, stress management, and production cost optimization, ongoing advancements in crystal growth technology, epitaxial processing, and manufacturing equipment will gradually resolve these issues.

JXT actively contributes to the GaN industry by providing 2- to 4-inch GaN single-crystal substrates and various epitaxial solutions, while also closely monitoring breakthroughs in 8-inch GaN substrate technology. With the large-scale production of 8-inch GaN substrates on the horizon, GaN technology is expected to play an increasingly significant role in the global semiconductor market, driving the widespread adoption of high-performance electronic devices.