New energy OBC heavy volume, Pine Jie SiC MOS takes the lead in the car with world-leading performance

In new energy vehicles, the on-board charger (OBC) is the key component that completes the conversion of AC power to DC power required by the battery, and determines the charging power and efficiency. The progress of OBC technology and the user’s charging experience have great Relationship. With the expansion of the electric vehicle market and the rise of the energy storage market, higher requirements are put forward on the performance of OBC. It is reported that leading domestic companies began to use SiC as OBC as early as 5 years ago. Now the technology of OBC is becoming more and more mature, the volume is getting smaller and smaller, the cost is getting lower and lower, and it is in the period of heavy volume growth.

However, there are not many domestic chip manufacturers that can make SiC MOS, and domestic automakers still use CREE, Roma, and ST products for SiC. The only domestic company that has passed the OBC silicon carbide test by the domestic car company as a startup company-Pine Jie, a young third-generation semiconductor power device fabless company, its SiC MOS products have been verified in the OBC application of new energy vehicles A major breakthrough, it has won tens of millions of orders from leading new energy automobile companies, and has begun low-key supply.

Dr. Huang Xing, Founder and President of Pine Jie Semiconductor (Source: Pine Jie Company)

OBC heavy volume, SiC supply chain resources are scarce

Some industry experts thought that as the entire charging pile, especially the ultra-fast charging pile, became popular, OBC would be taken from the car. Huang Xing, the founder and president of Pine Jie Semiconductor, said that this situation will not happen at present: “Because Although the power of OBC is relatively small, fast charging piles are generally 200 kW and 300 kW, while OBC is only 11 kW, and the maximum charging speed is 22 kW. This charging speed is definitely not the same. On the one hand, OBC is an emergency charging solution. Customers provide a great safety guarantee when using electric vehicles. As long as the 220V AC is plugged in, the vehicle can be guaranteed to be in a charged state.”

“On the other hand, with the popularization and application of electric vehicles, it also has the need to discharge externally as an energy storage battery. At present, some domestic car manufacturers have put two-way OBC on the car as a standard. As a two-way solution, SiC is used The most cost-effective, it is very similar to the energy storage solution. Because of the two-way flow of energy, only MOS can be used.”Huang Xing continued.

Nowadays, OBC’s technology is becoming more and more mature, the volume is getting smaller and smaller, and the cost is getting lower and lower. Huang Xing said that now is the time for OBC to increase its volume. For auto manufacturers, it is a strategy to conquer the city, and the rising auto factories are bound to compete for scarce SiC supply chain resources. At present, the global supply of SiC is no longer enough in the field of automobiles. It is reported that recently, a leading international company SiC MOS delivery date has just been extended from 52 weeks to 80 weeks.

As SiC continues to be in short supply, many major international manufacturers have announced expansions, and domestic investment in SiC is also increasing. As for the worry of overcapacity, Huang Xing said that it will not appear before at least 2025: “We see new The energy market will continue to grow steadily until 2025, and although the entire country’s SiC capacity investment is large, the quality has not yet reached the level that can be used for vehicles. At present, most domestic SiC capacity invested by friends It is mainly used for the application of diodes and unidirectional energy flow. Many new energy applications are mainly for bidirectional energy flow. Only MOS can be used instead of diodes. Moreover, the quality control and technical difficulties of the entire MOS are relatively large. Yes. Although a lot of domestic assets have been invested, these production capacities have not yet seen any signs that they can be released. Even if the production capacity is released enough, it should not be able to keep up with the market outbreak by 2025.”

Domestic SiC MOS is difficult to break through

At present, domestically produced SiC products are mainly based on SiC diodes, while the localization of SiC MOS is relatively more difficult. Investigating the reason, Huang Xing explained: “The SiC industry is relatively new at present. So far, many commercial softwares have made very inaccurate predictions when simulating silicon carbide. Big difficulty. Once a good device is designed in the simulation, it is completely different from the design. Because SiC is relatively a relatively small sub-industry, many simulation software will not specifically invest in SiC Too many resources lead to the lack of models in this area. This requires designers to analyze SiC from the lowest level of physical models, such as SiC’s own electron mobility, avalanche breakdown model, thermal simulation model, and process gate oxide growth. Materials are calibrated, and experiments are continuously iterated and perfected.”

“On the other hand, the cost of SiC itself is relatively high, and the cost of developing dozens of material numbers has increased tremendously. In addition, SiC processing is relatively difficult, and many factories do not have such processing conditions, which will greatly limit the entire R&D iteration. Speed, which is also an important reason why it is difficult for many SiC companies to launch mature products.” Huang Xingjie added.

Under the tutelage of “Father of IGBT” Jayant Baliga and ETO thyristor inventor Alex Q. Huang, Huang Xing has more than 10 years of experience in silicon carbide and gallium nitride power devices, and released more than 20 SiC/GaN mass productions during his stay in the United States from 2014 to 2017 Products, released the world’s first 6-inch SiC3300V MOSFET device, and invented the first bidirectional withstand voltage SiC junction terminal structure. In 2018, when the semiconductor industry was at a low point, Huang Xing saw opportunities in the Chinese semiconductor market: “I saw the prospect of SiC at the time. The companies that mastered this technology to produce this product were mainly companies in Europe, America and Japan, and China occupied For most of the needs, but there is no such company. I think it is more meaningful to come back to fill the gaps in the domestic industry. I chose to come back at that point in time.”

Thanks to years of accumulation in models, various mass production experience and customer application experience, and thanks to the support of the mature foundry X-FAB with 30 years of experience in the rapid iteration cycle, Pine Jie It has been able to develop rapidly in more than 3 years. In March 2019, Pinetech released the first compatible drive 650V GaN power device; in August of the same year, it completed the Gen3 1200V SiC MOS, filling the domestic gap; in 2020, it was released for use in 5G data centers, servers and industries. 650V, 1700V industrial-grade MOS for auxiliary power supply and 650V vehicle-grade MOS for on-board chargers; 1200V high-current automotive-grade MOS released in February 2021, applied to electric vehicle electric drive single tubes and modules; July 2021 , To complete the development of 1200V 62mm SiC module.

Self-built SiC module packaging production line to accelerate SiC on-board

Huang Xing pointed out that many domestic factories have made great achievements in the size of the car. The core of SiC on the car, which is relatively missing in China, is the SiC power module. From the high frequency, high speed and low power consumption of silicon carbide itself, SiC is no longer suitable for the use of traditional power modules. Now the more successful SiC modules on the market are still like Tesla’s T pack and the current mass production. The form of the applied board bridge module. In the past two years, the domestic silicon carbide power modules are relatively lacking. Therefore, Pinjie wants to use its first-mover advantage on the chip to continue to expand and accumulate the technology in the modules, and plans to build a production line for automotive silicon carbide module packaging.

Because Pinejie uses its own chips, it has accumulated a lot of data on the application of chips in industry and automobiles, and knows the advantages and characteristics of its own chips. Therefore, in the design of the entire module joint, the joint chip will be adjusted for the upper and lower linkages. And optimize, let the module adapt to the chip. For example, Infineon and other international manufacturers that do well in power modules, their success is also of great importance to the use of their own chips.

“There are many types of SiC defects. From the perspective of cost control and yield, some defects can be tolerated by industrial grade, but not by car rules. Chips that do not meet car rules can be singled out to make industrial grade products. As for some fatal ones. Defects can be screened out in advance. In addition, you can think of ways to request material factories to help optimize their products and find a compromise balance.” Huang Xing explained how to provide yield.

Huang Xing pointed out that the current yield rate of Pine Jie is above the average in the industry, with a comprehensive yield rate of 80%-90%, which varies from model to model. Generally, the yield rate of small and medium power chips will be above 90%, and if the power is too high, it will fall down. This is caused by the defects of the current SiC raw materials. If we put aside material defects and only talk about fab defects, the yield rate is more than 99%.

Comparison of SiC MOS indicators (Source: Pine Jie Company)

At present, Pinetech’s technology is benchmarked against CREE’s third-generation planar gate SiC MOS, with client evaluation, and its silicon carbide performance is among the top three in the world.

In the evaluation index HDFM (Rds(on) of the device × Qgd of the device), HDFM is an important parameter index to measure the pros and cons of power semiconductors. The lower the value, the smaller the comprehensive loss of the device and the higher the efficiency. Ideally, in the same application scenario, if Pine Jie’s SiC MOSFET consumes 10W, S brand 14W, C brand 11.8W, R brand 13.6W, and a domestic brand 20W. It can be seen that Pine Jie is the best among all planar gate technologies, and can provide customers with the best solutions in terms of switching loss and conduction loss.

In addition, in the actual measurement of some extreme resistance indicators, such as peak power, peak current and some avalanche tests, Pine Jie can meet the more demanding industrial requirements and vehicle regulations. The SiC MOS currently on the car is dominated by planar gate technology, and Pinetech insists on iterating on planar gate technology, making the HDFM indicator Rds(on)×Qgd smaller and smaller to maintain technological advancement.

Huang Xing revealed that construction of the production line is expected to start in early 2022, and samples will be available by the end of 2022.

In the current global SiC industry structure, the Chinese market has a rare opportunity. Huang Xing said: “One of China’s biggest opportunities now is the carbon peak and carbon neutral trend. It is now being deployed as a major national strategy. In addition, it is the global industrial chain. We have also received the attention of previous industry customers. With the spread of the global epidemic, the international industrial chain has been re-integrated, and products that may not be available abroad are now available in China, and on the whole, we have received a lot of products that were not available before. Chance.”

It is undeniable that from a global perspective, compared with IGBT, the entire industrial chain of SiC is still very fragile. This is especially true in China, where the demand side continues to expand, while the supply side is still in a stage of technological iteration and technical verification, and many production capacities have not yet been released. Pine Jie believes that the biggest challenge is to help material suppliers improve their capabilities, but this is not what they are good at. “This has brought us some questions about the management of the entire supply chain, including the cultivation of the supply chain. We can only learn war in the war. While we continue to accumulate our core technology, we must also find ways to help the upstream and downstream supply chains. Grow together with customers.” Huang Xing pointed out the current challenges. It is believed that as more responsible companies join and jointly promote the coordinated development of the upstream and downstream of the industrial chain, there will be opportunities to seize domestic opportunities and further accelerate the launch of local SiC MOS.