Silicon Carbide: A New Opportunity for the Development of the Power Semiconductor Industry

The semiconductor materials used in power devices are divided into three generations:

The first-generation semiconductor materials are elemental substances such as silicon (Si) and germanium (Ge). Due to their mature manufacturing processes and low production costs, silicon accounts for more than 95% of semiconductor devices and is currently the dominant semiconductor material.

The second-generation semiconductor materials are compound materials such as gallium arsenide (GaAs). Gallium arsenide semiconductors boast high electron mobility and a wider bandgap than silicon, giving them advantages like high breakdown voltage and high operating frequency. However, they also have drawbacks, including low mechanical strength, susceptibility to decomposition at high temperatures, slow growth rates, and high cost. Currently, they are mainly used in optoelectronic applications such as LEDs.

Third-generation semiconductor materials include wide-bandgap materials such as silicon carbide (SiC) and gallium nitride (GaN).

Improving energy efficiency (reducing energy consumption and losses) is a key direction for advancements in power semiconductor technology. The ideal goal is for power semiconductors to consume no power at all when conducting and to have zero leakage current when turned off. Currently, according to a report by the IEA, global electricity losses account for 20% of total electricity consumption—a significant waste from both an economic and environmental perspective. However, power semiconductor devices made from conventional silicon materials have already reached the theoretical limit of energy conversion efficiency.

Born from the application of third-generation semiconductor materials—such as silicon carbide and gallium nitride—these materials have become the next-generation technological direction for power semiconductors. According to the China Third-Generation Semiconductor Industry Technology Innovation Strategic Alliance, The performance advantages of third-generation semiconductor materials include: High electron drift velocity, Can reduce power consumption during energy conversion. Improve energy utilization efficiency; with a large bandgap and high critical breakdown voltage, the number of components required in high-voltage operating systems can be reduced. Promote system miniaturization and lightweight design. ; High thermal conductivity, Reduce the required cooling system 。

Compared to gallium nitride, silicon carbide is better suited for power systems operating at voltages above 1,000V, including medium- and high-voltage applications such as electric vehicles, charging stations, new-energy power generation systems, and high-speed rail traction systems. Once the technology for fabricating gallium nitride devices using silicon substrates matures, these devices will become more cost-effective compared to silicon carbide devices that rely on homoepitaxial substrates. In the future, in medium- and low-voltage applications, devices made from silicon carbide and gallium nitride materials will likely compete with each other.

Currently, silicon carbide devices are primarily used in power supplies and photovoltaic inverters, as well as in limited applications within the electric vehicle industry. The primary potential application markets remain untapped. 。

Between 2017 and 2019, the global silicon carbide power device market experienced an average compound annual growth rate of 39.7%. In 2019, the market size reached US$507 million, yet market penetration remained at just 1.27%, signaling the early stages of a promising trend.

Public information from various channels is relatively optimistic about the growth of the silicon carbide device market. It is estimated that by 2025, the global silicon carbide device market will exceed 3 billion U.S. dollars, with an average compound annual growth rate of as high as 34.5% over the next five years, and it is expected to continue growing thereafter.

From the perspective of growth drivers/downstream demand, in the foreseeable future, New energy vehicles (including supporting charging stations) will be the largest application scenario for silicon carbide devices, accounting for at least 50% of total demand. The growth rate far exceeds that of other markets.

Looking at the breakdown, currently, silicon carbide devices in electric vehicles are mainly used in on-board chargers (OBCs) and DC-DC converters. This helps to increase the charging speed of electric vehicles. By the end of 2018, more than 20 automakers worldwide had already adopted silicon carbide devices in their on-board chargers (OBCs). However, the market’s growth potential remains relatively limited.

Applying silicon carbide devices to the drive motor/inverter—i.e., the powertrain—of electric vehicles can significantly increase driving range, and the potential scale of such applications far exceeds that of other applications. Using silicon carbide devices in motor drives can not only reduce electrical energy losses and enhance power control but also shrink the size of the equipment—by about 50%—and lighten its weight. As a result, vehicle range can increase by 5% to 10%, or battery costs can be reduced accordingly by 5% to 10% (roughly equivalent to $200 to $600 per vehicle). Moreover, silicon carbide devices can also lower the cost of cooling systems and extend the service life of power batteries, making them entirely beneficial with no drawbacks. A rough estimate suggests that the potential value of silicon carbide devices used in the drive motors of each electric vehicle could exceed 10 times their current application value.

The trend in the application of silicon carbide devices for drive motors has become clear. Currently, most automakers plan to adopt silicon carbide devices in main inverters over the next few years. Due to cost considerations, silicon carbide devices are initially being deployed in high-end electric vehicles. Tesla is a pioneer in the application of silicon carbide devices; its Model 3’s drive motor is equipped with 24 silicon carbide MOSFET modules rated at 650V/100A. In 2020, BYD introduced the Han (high-performance version), which also features silicon carbide MOSFET-based motor control modules. Overseas component suppliers such as Bosch, ZF, and Delphi have all launched R&D programs for silicon carbide electric-drive systems. Moreover, the increase in power system voltage translates into faster charging speeds. Starting with the Porsche Taycan, as the voltage platform of high-end electric vehicle battery packs has been upgraded from 400V to 800V, the demand for silicon carbide modules will shift from 650V to 1200V.

In addition, the application of silicon carbide devices in the charging station market will also grow rapidly. The widespread adoption of new-energy vehicles will drive demand for charging infrastructure, and currently, there is a significant gap both domestically and internationally. Due to their performance advantages, silicon carbide devices are increasingly being used in high-power DC (fast-charging) charging stations.

In addition to new energy vehicles, High-voltage devices tailored to specific needs, such as those for rail transit and ultra-high-voltage power grids, are currently still under development and are expected to become commercially viable after 2025.

However, since the manufacturing process of silicon carbide is more complex than that of silicon and offers higher added value, downstream customers primarily use it in applications with high cost-effectiveness. It is not expected to replace silicon in low-end applications.

As mentioned above, silicon carbide devices boast outstanding performance advantages, have clearly defined application scenarios, and are actively being invested in by leading companies across the upstream and downstream segments of the industry chain. Yet, their current market penetration remains low. The underlying reason for this is— Constrained by two major barriers: high manufacturing costs and low technological maturity. Breaking through these two barriers is at the heart of the technological development direction. Each of the four stages in silicon carbide device manufacturing—substrate fabrication, epitaxy, chip processing, and packaging & testing—offers unique opportunities for advancement.

1) The manufacturing cost of silicon carbide devices is high. Currently, the costs of silicon carbide diodes and MOSFETs are roughly 2 to 3 times and 5 to 10 times higher, respectively, than those of comparable silicon products. However, downstream customers believe that the widespread price range for large-scale adoption of silicon carbide devices should be around 1.5 times that of their silicon counterparts. The primary factor driving these high costs is the high price of raw materials—especially the substrate wafers, which account for 50% of the cost of standard silicon carbide devices.

The properties of silicon carbide raw materials determine that their fabrication is more difficult and costly than that of silicon wafers. 。 In terms of preparation temperature, silicon carbide substrates must be produced in high-temperature equipment operating at 2,500 degrees Celsius, whereas silicon wafers can be fabricated at just 1,500 degrees Celsius. Regarding production cycles, silicon carbide wafers typically take about 7 to 10 days to produce, while silicon ingots require only two and a half days. As for commercially available wafer sizes, silicon carbide wafers currently come mainly in 4-inch and 6-inch diameters, whereas silicon wafers used for power devices are predominantly 8 inches in diameter. This means that silicon carbide single-crystal wafers yield fewer chips per wafer, resulting in higher manufacturing costs for silicon carbide chips.

Technological Evolution Direction Regarding substrates, leading overseas companies are expected to begin mass production of 8-inch wafers around 2022. In terms of epitaxy and devices, capacity and yield rates will continue to be improved.

2) The silicon carbide industry has not been developing for long and still requires further application validation. Unlike the silicon industry, which has accumulated a highly comprehensive dataset over decades of research, many performance conclusions about silicon carbide are derived from extrapolations based on silicon’s properties. As a result, numerous characteristic data points still require further empirical validation.

In addition, The product portfolio of silicon carbide power devices is not yet fully developed. From the perspective of the entire power semiconductor market, power devices come in a wide variety of types, including diodes, MOSFETs, IGBTs, and others, each suited to different application fields. However, at present, The silicon carbide device market is still dominated by diodes; MOSFETs have not yet been widely adopted, and IGBTs are still under development. Silicon carbide diodes are primarily used as a replacement for silicon diodes; they have lower structural complexity and are now widely commercialized. In 2019, silicon carbide diodes accounted for 85% of the silicon carbide device market, making them currently the most dominant type of silicon carbide device. Silicon carbide MOSFETs can replace silicon-based IGBTs, but their large-scale adoption remains constrained by issues related to product performance stability and device maturity. Silicon carbide IGBTs are still under development, and it is expected that prototype devices will not be available for another 5 to 10 years.

Technological Evolution Direction In terms of devices, we are developing high-voltage devices rated above 3.3 kV and introducing trench-based designs to enhance device performance and reliability. In terms of packaging, we will optimize the packaging process to fully leverage silicon carbide’s advantage of high-temperature resistance.

Strengthen top-level design, Develop a plan, concentrate efforts, advance technology, and strengthen the foundation.

· Develop strategic plans, outline technology development roadmaps, and explore approaches and methods for pooling resources from various stakeholders.

· Mobilize government and capital resources to foster industrial clusters, concentrate and optimize innovation resources, and pool efforts to overcome technological bottlenecks in equipment, materials, and devices.

· Strengthen basic research and encourage original innovation to provide industries with talent, technology, and creative input.

Improve the foundational platforms for public R&D, services, and production applications across the industrial chain.

· Build an open national innovation technology center and an internationalized public R&D and service platform to tackle core technologies and enrich innovation resources.

· Build a testing, validation, and application demonstration platform; refine product testing processes; assist enterprises in innovating applications; and strengthen system-level capabilities centered on application deployment.

Improve the industrial ecosystem, Grasp key areas such as talent, technology, applications, and international cooperation.

· Improve the talent development system and cultivate leading talents in areas such as entrepreneurship, innovation, and engineering technology.

· Build an open and orderly technical standards system, strengthen patent operations, and actively participate in the development of international technical standards.

· Promote international cooperation, enhance scientific research exchanges with overseas industry, academia, and research institutions, and facilitate the establishment of overseas technology R&D and innovation centers.