A Cool Look at the Silicon Carbide "Car-mounting" Climax

Source: The content is reprinted from China Electronics News by Semiconductor Industry Observer (ID: icbank) , author: Ji Xiaoting , thank you.

High humidity test of silicon carbide module on vehicle

2021 is known as the first year for domestic silicon carbide devices to be installed in vehicles. On August 1, 2021, BYD Semiconductor announced that the BYD Han motor controller used for the first time the high-performance silicon carbide power module independently developed and manufactured by BYD. This is the world's first and the only silicon carbide three-phase full-bridge module in China that has been installed in large quantities in motor drive controllers.

In December, domestic silicon carbide power device supplier Painjie Semiconductor's silicon carbide MOSFET won tens of millions of orders from leading new energy companies. On December 26, CRRC Times Electric released the C-Power220s product, claiming to be the first domestic high-power electric drive product based on independent silicon carbide. On December 30, Basic Semiconductor, a manufacturer of automotive-grade silicon carbide power semiconductors, announced that its automotive-grade silicon carbide power module manufacturing base in Wuxi was officially put into operation, and the first batch of silicon carbide module products rolled off the production line and had passed the selection and testing of domestic leading automakers.

Basic Semiconductor Pcore6

Based on its good market prospects, my country invested in dozens of silicon carbide-related projects last year. Among them, more than a dozen investments were related to silicon carbide devices. On July 18, 2021, the Century Golden Light Project was officially signed with Jinyi New District, Jinhua City, Zhejiang Province. The total investment of the project is 3.5 billion yuan. It will build an annual production line of 220,000 6-8 inch silicon carbide chips. The project will be completed in three phases. After full production, it can achieve an annual output value of about 4 billion yuan.

On December 30, Junlian Electronics announced that they held a launching ceremony for the "800V Multi-Integrated Silicon Carbide Power Domain Controller Project for Vehicles" in Hefei Economic Development Zone. The total investment of the project is about 1 billion yuan, and it is mainly engaged in the research and development, sales and service of multi-integrated power domain controllers based on silicon carbide materials (including MCU, OBC, DCDC, DCAC, PDU, intelligent control software, Internet of Vehicles and other products). At present, the development of the second-generation automotive 800V multi-integrated silicon carbide power domain controller product has been completed.

From the perspective of industrial structure, my country's silicon carbide industry development pattern covering the entire industrial chain has taken shape. From substrates to epitaxial wafers to devices and modules, my country has formed a relatively complete product supply chain. In terms of substrates and epitaxial wafers, some Chinese companies have been able to supply international manufacturers, including global automotive semiconductor manufacturers such as STMicroelectronics.

It is almost an industry consensus that silicon carbide is very "hot". The development of new energy vehicles has provided a rare opportunity for domestic silicon carbide device manufacturers to develop automotive-grade products. Due to the advantages of silicon carbide materials such as high carrier mobility and high breakdown field strength, the heat loss of silicon carbide MOSFET in the medium and low power range is much lower than that of silicon-based IGBT. It is for this reason that major semiconductor suppliers have extremely high expectations for the market prospects of silicon carbide MOSFET.

Wen Yu, the automotive industry director of Basic Semiconductor, said in an interview with China Electronics News that the annual sales volume of new energy vehicles in China is expected to exceed 10 million by 2025. It is estimated that about 40% to 50% of these vehicles will use silicon carbide motor controllers. In other words, the number of vehicles using silicon carbide power modules will reach 4 million to 5 million.

Chen Dongpo, deputy general manager of Sanan Optoelectronics, is also optimistic about the penetration of silicon carbide into automotive power devices. He believes that silicon carbide will be preferentially penetrated in models with long mileage, because the driving force for the introduction of models with long mileage is relatively strong. It is expected that in 2023-2024, 80%~90% of models with a range of more than 500 kilometers will import silicon carbide devices. Models with a range of 400 kilometers to 500 kilometers are expected to be introduced after 2024, and the overall penetration rate of this type of vehicle will reach about 40%. For models below 400 kilometers, it is expected that they will gradually follow up after 2025, and the overall penetration rate of this type of vehicle will not be very high, estimated to be around 10%.

Silicon carbide module on-vehicle testing

At present, some people believe that the main obstacle to the application of silicon carbide in automotive-grade products is that the cost is too high. According to the quotation of supply chain companies, the current price of an imported silicon-based IGBT module used in a new energy vehicle is about 1,500 to 1,700 yuan. The price of silicon carbide MOSFET power modules is 2.5 to 3 times that of silicon-based IGBT modules. This means that if silicon carbide MOSFET modules are to be used to replace silicon-based IGBT modules, the cost of each vehicle will need to be increased by about 2,200 to 3,400 yuan.

Regarding this data, Wen Yu said that the difference in vehicle cost between silicon carbide MOSFET modules and silicon-based IGBT modules is not large. Under the same voltage platform, replacing IGBT with silicon carbide MOSFET modules can achieve a 3% to 5% performance improvement for the entire vehicle, which means that in vehicles with the same range, the battery capacity required for vehicles using silicon carbide MOSFET can be reduced by 3% to 5% compared to vehicles using silicon-based IGBTs. For example, a vehicle with a range of 400 km and a power consumption of about 60 kWh can use about 3 kWh less of battery, which translates to a battery cost reduction of about 3,000 yuan, which is similar to the cost increase of silicon carbide modules. This does not include the cost reduction in wires, heat dissipation, volume, etc. after using silicon carbide.

Automotive-grade module production base

From this point of view, silicon carbide MOSFET will not increase the cost of the whole vehicle. And as the production of silicon carbide MOSFET further increases, the price of single silicon carbide is expected to fall.

Although my country's silicon carbide production lines are relatively complete, there are still shortcomings in device preparation. Wen Yu said in an interview with a reporter from China Electronics News that there is little difference between the equipment and raw materials used by Chinese companies and foreign manufacturers.

Under such circumstances, there are differences in the chips produced, which is mainly caused by the production process. Due to the particularity of silicon carbide materials, the difficulty of its production depends largely on the process technology and level adopted. The gap in process brings about a gap in performance and reliability, which is also one of the reasons why it is difficult to install domestic silicon carbide power semiconductors on vehicles.

The lack of relevant process technology and professional talents is one of the difficulties that my country is currently facing in developing automotive-grade silicon carbide power devices. In addition, it is also restricted by the current development obstacles of my country's integrated circuit industry: the lack of high-end equipment and high-performance materials.

Lv Penghao, senior analyst at CCID Consulting, said in an interview with China Electronics News that the current transition period is from 6-inch to 8-inch silicon carbide wafers. The supply of 8-inch equipment will be a challenge for domestic companies. In addition, the high-end materials required in the silicon carbide preparation process, such as photoresist and high-purity gas, will still rely on imports.

The booming investment market reflects the importance that relevant companies and local governments attach to silicon carbide production lines. However, looking across the country, we can find that although there are many companies in my country that have entered the automotive-grade silicon carbide power devices and modules, they are all small in scale and have obvious characteristics of being "small" and "scattered". There are even fewer companies entering the automotive-grade silicon carbide power device field.

Wang Xujin, dean of the Microelectronics Research Institute and the Semiconductor Manufacturing Research Institute of Shenzhen University, said that automotive-grade products have higher requirements for reliability and safety than consumer-grade and industrial-grade products, and require long-term investment. In Wang Xujin's view, domestic automotive-grade chip companies are "guerrillas", while overseas companies are "group armies". If we want to achieve wider application of domestic automotive-grade power semiconductors, we need to integrate the "guerrillas", and the next five years will be their integration period.

Even though the entire industry is optimistic about the market prospects of automotive-grade silicon carbide, it is not recommended for manufacturers to invest in large quantities. Lu Penghao said that after all, the current automotive silicon carbide market space is limited. Overall, the current volume is only tens of billions to hundreds of billions, and its market potential needs to be released slowly.

Wang Xujin also said that the technology of silicon carbide power devices is still in the process of evolution, and it is difficult for Chinese companies to reach the international leading level, and they also need to pay attention to the risks involved.

Faced with the problems encountered in installing automotive-grade silicon carbide power semiconductors in my country's vehicles, Wen Yu proposed three solutions.

First, continue to train and reserve talents. To build an automotive-grade silicon carbide wafer flow line and module packaging line, it is necessary to train a large number of talents with professional skills. Faced with the situation that domestic automotive-grade silicon carbide products are still catching up with the technical level of overseas manufacturers, Wen Yu believes that in order to realize the industrialization of silicon carbide in my country, it is necessary to introduce a large number of overseas talents.

Secondly, we must ensure that the supply of equipment and raw materials is not restricted. While adopting overseas equipment and raw materials, we must increase the development and industrial application of domestic production and testing equipment, as well as the improvement of the technology, quality and production capacity of domestic high-performance substrates and epitaxial materials.

Third, there should be in-depth cooperation between the upstream and downstream of the industry. For automotive-grade products, on-vehicle verification is a major hurdle. If the upstream and downstream cooperation of products can be achieved as soon as possible, it will help silicon carbide suppliers avoid many detours. International automotive-grade power semiconductor companies including STMicroelectronics, Infineon, and Rohm have established good partnerships with domestic and foreign automakers. Although the cooperation between my country's auto companies and silicon carbide power semiconductor companies has been launched, it is still necessary to increase the promotion of deeper cooperation between the upstream and downstream of the industrial chain.