Not long ago, TAISIC MATERIALS CORP successfully produced Taiwan's first 8-inch SiC substrate.
Now, XMHT Electronic Materials Technology Group, a leading manufacturer of silicon carbide wafers in China, has successfully achieved 8-inch (200 mm) homogeneous epitaxial growth of silicon carbide, becoming the first technology company in China to own and implement this technology; It also marks that China has mastered the relevant technology for the epitaxial growth of 8-inch silicon carbide.
By overcoming problems such as higher stress, easier cracking, and more difficult to control the thickness uniformity of the epitaxial layer on an 8-inch substrate, the homogeneous epitaxial growth of silicon carbide based on domestic substrates has been successfully achieved. The epitaxial layer has a thickness of 12 um and a thickness non-uniformity of 2.3%; The doping concentration is 8.4 × ten 1 ⁵ cm ˉ3， Heterogeneity of doping concentration ＜ 7.5%; Surface defect (Carrot, Triangle, Downfall, Scratch) density ＜ 0.5 cm ˉ2。
XMHT has long been committed to the research of wide band gap semiconductors such as group III nitride and silicon carbide, and has continuously promoted the development of wide band gap semiconductors in China for many years, cultivating a large number of innovative talents for the industry.
The person in charge of the above research team stated that this breakthrough marks that China has mastered the relevant technology for the epitaxial growth of 8-inch silicon carbide. The implementation of this technology will inject new impetus into the development of China's silicon carbide industry, while promoting the development of new energy and other related fields.
XMHT has been committed to developing and producing SiC epitaxial wafers, and the company has nearly 100 "6-8 inch SiC epitaxial wafer production lines."
SiC enters the eight-inch era
Compared to the first and second generation semiconductor materials, SiC has a series of excellent physical and chemical properties, including high breakdown electric field, high saturated electron velocity, high thermal conductivity, high electron density, and high mobility, in addition to the band gap width.
The critical breakdown electric field of SiC is 10 times that of Si and 5 times that of GaAs, which improves the withstand voltage capacity, operating frequency, and current density of SiC based devices, and reduces the conduction loss of devices. With a higher thermal conductivity than Cu, there is no need for additional heat dissipation devices when using the device, reducing the overall volume. These are the great advantages of SiC materials.
SiC materials are widely used in aerospace, new energy vehicles, rail transit, photovoltaic power generation, smart grid, and other fields.
Entering eight inches, the number of theoretically available bare chips (GDPW, also known as PDPW) per wafer increases significantly.
Currently, the mainstream silicon carbide single crystal and epitaxial growth is still at the 6-inch stage, and expanding size has become the main path to reduce costs and increase efficiency in the industrial chain. However, there are still many technical challenges in the process of moving towards 8-inch growth.
Silicon based wafers have begun to move from 8 inches to 12 inches. Can the production experience of silicon wafers help develop SiC wafers to a larger area?
Compared to silicon wafers, the manufacturing difficulties of 8-inch SiC mainly focus on substrate growth, substrate cutting, and oxidation processes.
The third generation semiconductor industry chain, including SiC, includes substrate epitaxial design, manufacturing, and packaging. One of the major reasons for the high cost of SiC devices is the difficulty in manufacturing SiC substrates.
The data shows that the substrate cost accounts for approximately 50% of the total wafer processing cost, the epitaxial wafer accounts for 25%, the device wafer manufacturing process accounts for 20%, and the packaging and testing process accounts for 5%. The cost of SiC substrates is high, and the production process is complex. Compared to silicon, SiC is difficult to process.
In terms of the development process of China's 8-inch SiC production line, some companies and units in China have made breakthroughs in mass production or initiated projects as pre research projects. This includes: SXSK Crystal Technology Corporation has successfully developed and produced 8-inch silicon carbide substrates in small batches; BJTK also launched the research and development of 8-inch SiC chips in 2020.
In addition, in 2022, China is also making continuous breakthroughs in the technology of 8-inch silicon carbide epitaxial wafers:
In September 2022, Showa Electric announced that they had successfully produced 8-inch SiC epitaxial wafers and began providing samples using their own 8-inch SiC substrates.
In April 2022, GDTY Semiconductor announced that it would build the world's first 8-inch silicon carbide epitaxial wafer production line. The project is planned to start construction in 2022, and is expected to be completed and put into production in 2025.
In May 2022, the Chen Xiaolong research team of the Institute of Physics of the Chinese Academy of Sciences announced that it had successfully developed a single 4H crystal form of 8-inch SiC crystal, with the thickness of the crystal blank approaching 19.6 mm, and processed an 8-inch SiC chip with a thickness of about 2mm. Three Chinese invention patents have been applied for related work.