SiC Wafer Price Trends and 2026 Outlook

SiC Wafer Prices: Shifting from "On the Way Down" to "Changing the Pace of Decline"

In 2024, the SiC power semiconductor market experienced slower-than-expected demand growth, prompting some manufacturers to revise their production plans. In response to this "pause," the question of how wafer prices will move has a direct impact on a wide range of decisions, from cost calculations for device design to the restructuring of procurement strategies. To forecast prospects for 2026, we first need to understand the underlying structure: "Why have SiC wafers been so expensive?"

The manufacturing of SiC wafers requires a completely different process than silicon wafers. SiC single crystals are grown using methods like the Acheson process or modified Lely method. Because growth rates are extremely slow, it takes several days to produce a single 6-inch wafer. This "slow crystal growth" is the root cause of the cost, creating a structure where dramatic cost reductions through mass production effects, as seen with silicon wafers, are difficult to achieve. Furthermore, managing defect density is directly linked to quality, making yield improvement the key to price reduction.

The Transition to 200mm as a Turning Point for Price Structure

The transition from 6-inch (150mm) to 8-inch (200mm) wafers significantly increases the number of chips obtainable per wafer. Based on a simple area ratio, an 8-inch wafer has approximately 1.78 times the area of a 6-inch wafer, meaning more devices can be produced for the same process cost. This is widely recognized within the industry as directly contributing to the reduction of cost per SiC device.

The issue is, "When will the transition become widespread?" Currently, Wolfspeed, Coherent (formerly II-VI), Rohm, and Mitsubishi Electric, among others, are developing and preparing for mass production of 8-inch SiC wafers. Mitsubishi Electric has strengthened its collaborative development partnership with Coherent for 8-inch SiC substrates, indicating a move to secure high-quality substrates for its new plant in Kumamoto. However, it is believed that it will take a gradual process, even beyond 2026, for 8-inch mass production to reach a level that impacts market prices.

Therefore, a simple expectation of "a significant price drop in 2026" may not align with reality. A more accurate perspective is that "the progress of the 8-inch transition will vary by manufacturer, and the pace of price decline will change in conjunction with the selection of suppliers."

This area ratio implies that even if wafer prices remain at the same level, the cost per chip will theoretically decrease significantly. However, the actual effect depends on process yield and production volume, so it is premature to equate this figure directly with a percentage price reduction.

The Demand Plateau is Altering the Structure of Wafer Price Negotiations

The downward revision of demand forecasts for SiC devices for EVs leading up to 2024 is due to a slowdown in EV sales growth. As some major OEMs have postponed the adoption timing of SiC for next-generation inverters, SiC device manufacturers' inventories have piled up, and the pace of wafer orders has slowed.

This situation creates short-term downward price pressure for wafer suppliers. On the other hand, it can be seen as an adjustment with device manufacturers in the form of revisions to long-term contracts. While the demand plateau may present an "opportunity for favorable negotiations for buyers," maintaining relationships with suppliers is often prioritized from the perspective of ensuring long-term supply.

The SiC wafer market still has a limited number of suppliers, with key players including Wolfspeed, Coherent, SiCrystal (under Bosch), Rohm, and Showa Denko Materials. This high concentration of suppliers is intertwined with the risk that supply constraints will once again push up prices when demand enters a recovery phase.

From a Device Design Perspective: "Chip Size" Has More Impact Than Wafer Price

Alongside the discussion of wafer prices, there is a crucial perspective from the design side. To reduce the cost of SiC devices, instead of waiting for wafer prices to fall, there is a direction to "achieve the same performance with a smaller chip area."

The key here is the improvement of on-resistance (RonA, on-resistance x chip area). If RonA decreases, the same on-resistance specifications can be achieved with a smaller chip, increasing the number of chips that can be obtained from a single wafer. Rohm's fourth-generation SiC MOSFETs are said to achieve both low RonA and high short-circuit withstand capability through their proprietary device structure. Such technological advancements work to relatively reduce the impact of wafer costs.

However, there is a trade-off between improving RonA and short-circuit withstand capability. In SiC MOSFETs, increasing channel density to lower on-resistance tends to concentrate excessive power during a short circuit, leading to a decrease in short-circuit withstand time (SCWT).

This trade-off remains a design constraint even if wafer prices fall. The balance between designs that aim to reduce on-resistance for higher efficiency and designs that ensure reliability through short-circuit protection will become a technical and business decision-making axis when selecting SiC MOSFETs.

Short-Circuit Withstand Time: An "Invisible Cost"

When discussing SiC wafer price trends, attention often focuses solely on the cost of the device itself. However, when examining the cost structure of the entire system, the design cost of short-circuit protection circuits cannot be ignored.

SiC devices are small and have high current density. This is the flip side of being able to obtain more chips from a single wafer, and the temperature rise during a load short circuit is faster than with Si devices. While silicon IGBTs often had a short-circuit withstand time of around 10μs, SiC MOSFETs sometimes list typ. 3μs, as seen with Microchip's products.

This 3μs figure means that the protection circuit must detect the short circuit and turn off the device within 3μs. The DESAT (de-saturation) function is widely used for short-circuit protection in SiC MOSFETs. This method monitors the drain-source voltage (VDS) in the on-state and turns off the transistor when overcurrent is detected. When designing this DESAT circuit, parameters such as trigger threshold (VDESAT), DESAT current (IDESAT), and short-circuit blanking time become important considerations.

The shorter short-circuit withstand time increases the complexity of selecting a gate driver and designing protection circuits, ultimately impacting system-level costs. Even if wafer prices fall, the structure where these peripheral design costs remain unchanged will persist.

What to Confirm for 2026

To assess the "outlook" for price trends, there are three main axes to consider.

First, the schedule for mass production startup of 8-inch wafers. The timing of mass production start announced by each wafer supplier, and whether it aligns with the product roadmaps of device manufacturers, will provide clues for predicting when actual market prices will be affected.

Second, the recovery curve of demand for EVs. The timing of the tightening of wafer supply and demand will change depending on when the current plateau ends. It is also worth observing whether demand for industrial equipment and renewable energy, not just for automotive applications, can function as a buffer.

Third, the pace of technological evolution in device structures. As exemplified by Mitsubishi Electric's case of improving short-circuit withstand capability by introducing a p-type protective layer in trench-type SiC MOSFETs, the extent to which manufacturers' structural improvements can mitigate the trade-off between RonA and short-circuit withstand capability will change the range of device selection.

The 2026 outlook for SiC wafer prices is not a simple dichotomy of "falling" or "not falling." It only becomes a meaningful forecast when conditions are narrowed down to "which manufacturer's wafer size, and for which application." The actual reasons for price fluctuations lie at the intersection of the progress of the 8-inch transition, the timing of demand recovery, and the technological competition in device structures.