1. Technical difficulties and breakthroughs in Physical Vapor Transmission (PVT) method

PVT method is currently the mainstream technology used for SiC single crystal growth, which involves high-temperature sublimation of silicon carbide raw materials and recrystallization to produce SiC single crystals. Although PVT technology is mature, there are still several technical difficulties and challenges:

Defect control: SiC crystals are prone to defects such as microtubes and dislocations during the growth process, which can affect the performance of power devices. In order to reduce defect density, it is necessary to optimize crucible design and growth parameters, especially to improve the control of microtubes and dislocations.

The problem of crystal expansion: With the increasing demand for large-sized SiC crystals, expansion has become a key issue. Especially in crystal growth of 8 inches and larger, technical issues such as temperature field uniformity and stress control must be addressed to ensure the quality of the crystal.

Phase transition suppression: SiC crystals have over 200 crystal forms, and accurately controlling growth conditions to avoid the formation of non target crystal forms (such as 6H SiC) is another technical challenge.

2. Future silicon carbide crystal growth technology

The future SiC crystal growth technology will mainly develop in the following directions:

Liquid phase method (LPE): Liquid phase method, as a potential new technological route, may become the mainstream technology in the future due to its low substrate defects and high quality. At present, Japan's Oxide company has started using liquid-phase method to produce 8-inch SiC substrates and plans to deliver samples. Domestic manufacturers such as Tianyue Advanced are also actively deploying liquid-phase technology.

Visual crystal growth technology: By combining existing PVT method silicon carbide crystal growth equipment with advanced equipment such as X-ray angle measuring instruments and computed tomography (CT) technology, a visual silicon carbide crystal growth technology is developed. This will enable real-time monitoring and adjustment of every detail during the growth process, thereby better controlling crystal quality. Jingsheng Corporation has successfully developed a visualized 8-inch resistive silicon carbide single crystal furnace and verified it on the client side.

12 inch SiC crystal growth technology: With the increasing demand for large-sized substrates, breakthroughs in 12 inch SiC crystal growth technology have become particularly important. The production of 12 inch substrates will reduce the cost of subsequent products and promote the popularization of SiC in more application fields. Tianyue Advanced and Shuoke companies have also made relevant technological progress in this field.

Al+silicon carbide crystal growth technology: By utilizing artificial intelligence (AI) technology and neural network analysis of crystal growth data, the growth process can be optimized, growth efficiency can be improved, and defects can be reduced. This technology is expected to become an important tool for SiC crystal growth in the future.

3. Current market conditions and development challenges

Currently, silicon carbide substrate manufacturers are undergoing a technological transition from 6-inch to 8-inch substrates. The 6-inch substrate technology is relatively mature, but its production cost is high, and the price has dropped significantly to 2500-2800 yuan (a decrease of more than 40% from early 2023). Compared to this, the development of 8-inch substrate technology is still in the stage of small-scale production, and due to issues such as yield and uniformity, the price remains between 8000-10000 yuan.

With the intensification of competition, many small and medium-sized substrate manufacturers adopt low price strategies to compete for market share, which leads to serious "involution" and may result in low-quality substrate products, thereby affecting the product quality and experience of downstream application manufacturers. Long term price competition below cost may put some substrate manufacturers at risk of capital chain breakage, and even lead to bankruptcy liquidation.

4. Response strategies and industry outlook

Reducing costs is the key to achieving sustainable development for large factories while ensuring product quality. Major manufacturers should strive to promote large-scale production of 8-inch substrates to consolidate market share and lay the foundation for possible breakthroughs in 12 inch substrate technology in the future. For small and medium-sized manufacturers, it is recommended to focus on technological breakthroughs in 8-inch substrates, actively seek strategic partners with financial strength, and avoid blindly following the trend and investing too early in the development of 12 inch substrate technology.

Ultimately, the manufacturers who first mastered the large-scale production of 8-inch substrates will further consolidate their market position, move towards the transformation from burning money to making money, and have the ability to develop towards 12 inch technology, further enhancing industrial competitiveness.

5. Conclusion

With the increasing demand for silicon carbide materials in the global semiconductor industry, especially in fields such as new energy vehicles, 5G communication, and smart grids, the production technology of SiC substrates will continue to advance. In the future, new technologies such as liquid-phase method, visualization technology, and 12 inch technology will become important development directions in the industry. Substrate manufacturers should be wary of low price competition and focus on technological innovation and production efficiency improvement in order to stand undefeated in the fiercely competitive market.