In the power semiconductor industry, silicon carbide (SiC) has emerged as the core material of the third-generation semiconductors. With the rapid growth of electric vehicles, renewable energy, energy storage, and power electronics, the demand for larger and higher-quality SiC substrates is increasing significantly. Recently, a hot topic has been whether 8-inch (200mm) 4H-N type SiC substrates will become the mainstream. This article provides an in-depth analysis from technical, market, and supply chain perspectives.
 

1. Why 8 inch, 4H, and N-Type?

8-inch (200mm): Compared to today’s mainstream 6-inch (150mm) substrates, the wafer area increases by about 78%, theoretically enabling more chips per wafer and lowering the cost per device. This potential benefit is critical for mass production.

4H-SiC: The dominant polytype for power devices, offering higher electron mobility and breakdown field strength than alternatives such as 6H. It is the optimal choice for high-voltage, high-efficiency applications.

N-Type: Electron-conductive substrates, suitable for mainstream power devices such as MOSFETs and Schottky diodes.

This combination represents the natural upgrade path for the power device industry and is the focus of both material suppliers and downstream manufacturers.

2. Drivers: Why Could It Become Mainstream?

Strong Market Demand: Applications such as EV inverters, on-board chargers, PV inverters, energy storage systems, and fast-charging stations are driving rapid growth. SiC’s efficiency and low-loss advantages are becoming essential.

Cost Reduction Potential: Larger wafers allow more chips per batch. As process maturity and yields improve, 8-inch production will unlock clear cost advantages.

Technology Breakthroughs: Global leaders such as Wolfspeed and Coherent have already demonstrated 8-inch wafers and begun building production lines. Chinese companies like TianKehuaDa and NSSC have also produced 8-inch samples and entered customer qualification stages.

Policy & Capital Support: SiC is prioritized as a key strategic material for third-generation semiconductors, with strong backing from governments and investors, accelerating ecosystem development.

3. Challenges and Bottlenecks

Yield Challenges: Larger SiC crystals are more prone to defects such as micropipes, stacking faults, warpage, and cracks—directly impacting yield and cost.

Supply Chain Gaps: Slicing, grinding, polishing, epitaxy, and inspection tools for 8-inch wafers still require upgrades, and standardization across the value chain remains incomplete.

Cost Balance Issues: If yields remain low, 8-inch wafers could end up being more expensive than 6-inch wafers in the short term.

Long Qualification Cycles: Device makers need years to adapt process flows, redesign devices, and complete reliability verification on new wafer sizes.

4. Timeline Expectations

Short Term (1–2 years): 6-inch substrates will continue to dominate. 8-inch will mainly remain at the R&D and small-scale sampling stage.

Medium Term (3–5 years): With yield improvements and cost reductions, 8-inch substrates may begin scaling into automotive-grade power devices, with leading vendors entering mass production.

Long Term (5+ years): 8-inch substrates are likely to become the mainstream industry standard, though 6-inch wafers may continue to coexist to serve cost-sensitive or niche markets.

5. Global Vendor Progress

Wolfspeed (USA): Built the world’s first 8-inch SiC wafer fab and is ramping toward mass production.

Coherent (USA): Demonstrated 8-inch samples and is advancing R&D.

TianKehuaDa (China): Produced high-quality 8-inch substrates, with some customers already in validation.

NSSC (China): Achieved notable progress in 8-inch R&D.

ROHM & Sumitomo Electric (Japan): Actively investing in 8-inch development with plans for gradual production.

The global progress clearly shows that 8-inch SiC is a shared consensus, and the competition now lies in scaling yields and production capabilities.

Conclusion

8-inch 4H-N type SiC substrates are poised to play a pivotal role in the future of power semiconductors. Their larger size promises cost advantages, supported by market demand, policies, and ongoing technological breakthroughs. However, in the short term, 6-inch substrates will remain dominant, while 8-inch will act more as a “strategic reserve” and “future standard.” Over the next 3–5 years, we can expect rapid adoption as yields improve and the supply chain matures. In the longer term, 8-inch substrates are set to become the mainstream, driving the next stage of power semiconductor growth.