As per a recent announcement by Nanjing Release, the National Third-Generation Semiconductor Technology Innovation Center (Nanjing) has successfully developed a key technology for the manufacturing of trench-type silicon carbide (SiC) MOSFET chip after four years of independent research. This breakthrough surpasses the performance limitations of planar SiC MOSFET chip, marking the first achievement of its kind in China.

SiC is one of the main representatives of wide bandgap semiconductor materials, characterized by its wide bandgap, high critical breakdown electric field, high electron saturation velocity, and high thermal conductivity. SiC MOSFET primarily comes in two structures: planar and trench, predominantly the former in current SiC MOSFET chip field.

Planar SiC MOS structure features simple process, good cell consistency, and relatively high avalanche energy. However, it faces the issue of JFET effect caused when current is confined to a narrow N-region near the P-body, which increases the on-resistance, and the large parasitic capacitance.

Trench structure refers to embedding the gate into the substrate to form a vertical channel, which allows for increased cell density, elimination of the JFET effect, optimal channel mobility, and significantly reduced on-resistance compared to planar structure. However, the trench process is more complex, with poorer cell consistency and lower avalanche energy.

“The key lies in the process,” explained Huang Runhua, Technical Director at the National Third-Generation Semiconductor Technology Innovation Center (Nanjing).

He noted that SiC is extremely hard, so converting from a planar to a trench structure means “digging a trench” in the material, which must be done with precision to avoid unevenness. During fabrication, the etching process’s precision, etching damage, and residual surface materials critically impact the development and performance of SiC devices.

To address these issues, the Innovation Center organized a core R&D team along with a full support team, and finally established a novel process flow following four years of continuous experimentation with new processes.

They overcame the challenges of precise, stable trench etching and successfully manufactured trench-type SiC MOSFET chip, improving conduction performance by about 30% compared to planar type.

The center is currently developing trench-type SiC MOSFET chip, with the goal of launching trench-type SiC power devices within a year, which are expected to be introduced to applications such as electric vehicle drivetrains, smart grids, photovoltaic energy storage.

What impact does this breakthrough have on our lives and the semiconductor industry? Huang explained, using electric vehicle as an example, that SiC power devices inherently offer power-saving advantages over silicon devices, potentially increasing lifespan by about 5%, and trench structure allows for designs with even lower resistance.

With the same conduction performance, this enables a higher-density chip layout, reducing chip usage costs.

Now, the National Third-Generation Semiconductor Technology Innovation Center (Nanjing) has already started research on SiC superjunction devices. “This structure outperforms the trench-type structure and is currently under development,” Huang Runhua revealed.

Read more

• [News] A 8-Inch SiC Wafer Fab Co-Built by San’an and ST to Start Production Soon
• [News] ST to Build a New 8-Inch SiC Facility in Italy with EUR 5 Billion

(Photo credit: DRAMeXchange)

As per Chongqing News Broadcast, the San’an-ST project, with a total investment of approximately CNY 30 billion, is close to completion. The substrate factory is expected to start production this month, two months ahead of schedule.

The project, jointly developed by Chongqing San’an and ST, includes a chip factory and a substrate factory, focusing on the production of SiC power chips and substrates. The substrate factory, fully funded by San’an Semiconductor, is set to produce 480,000 8-inch SiC substrates annually.

The chip plant, a joint venture between San’an Semiconductor and ST, aims for an annual production capacity of 480,000 automotive-grade SiC MOSFET power chips.

San’an, through its wholly-owned subsidiary Hunan San’an, established Chongqing San’an for the substrate factory. The total investment for this factory is approximately CNY 7 billion, focusing on the growth and manufacturing of SiC substrates, with an annual production capacity of 480,000 8-inch SiC substrates.

San’an STMicroelectronics, a joint venture between Hunan San’an (51%) and ST (China) Investment (49%), was established in August 2023 with a registered capital of USD 612 million.

This chip factory has a total investment of USD 3.2 billion and aims for an annual revenue of CNY 13.9 billion, with an annual production capacity of 480,000 8-inch automotive-grade SiC MOSFETs.

San’an has disclosed that the project is currently in the critical stage of equipment installation and commissioning, and the substrate factory is expected to be ready for operation by the end of August, while the chip factory is projected to be fully operational by the end of November.

Read more

• [News] ST to Build a New 8-Inch SiC Facility in Italy with EUR 5 Billion
• [News] A Price War in SiC Wafer Sector seems to Start

(Photo credit: STMicroelectronics)

The global automotive industry is pouring billions of dollars into SiC semiconductors, hoping that they could be key to transforming vehicle power systems. This shift is rapidly changing the supply chain at all levels, from components to modules.

In the previous piece “SiC vs. Silicon Debate: Will the Winner Take All?,” we explored SiC’s unique physical properties. Its ability to facilitate high-frequency fast charging, increase range, and reduce vehicle weight has made it increasingly popular in the market of electric vehicles (EVs).

Research from TrendForce shows that the main inverter has become the first area for a substantial penetration of SiC modules. In 2022, nearly 90% of all SiC usage in conventional vehicles was in main inverters. As demand grows for longer range and quicker charging times, we’re seeing a shift in vehicle voltage platforms from 400V to 800V. This evolution makes SiC a strategic focus for automotive OEMs, likely making it a standard component in main inverters in the future.

However, it is common for now that SiC power component suppliers fail to meet capacity and yield expectations – a challenge that directly affects car production schedules. This has led to a struggle for SiC capacity that is impacting the entire market segment.

Device Level: Burgeoning Strategic Alliances

Given the long-term scarcity of SiC components, leading OEMs and Tier 1 companies are vying to forge strategic partnerships or joint ventures with key SiC semiconductor suppliers, aiming to secure a steady supply of SiC.

In terms of technology, Planar SiC MOSFETs currently offer more mature reliability guarantees. However, the future appears to lie in Trench technology due to its cost and performance advantages.

Infineon and ROHM are leaders in this technology, while Planar manufacturers like STM, Wolfspeed, and On Semi are gradually transitioning to this new structure in their next-generation products. The pace at which customers embrace this new technology is a trend to watch closely.

Module Level: Highly-customized Solutions

When it comes to key main inverter component modules, more automakers prefer to define their own SiC modules – they prefer semiconductor suppliers to provide only the bare die, allowing chips from various suppliers to be compatible with their custom packaging modules for supply stability.

For instance, Tesla’s TPAK SiC MOSFET module as a model case for achieving high design flexibility. The module employs multi-tube parallelism, allowing different numbers of TPAKs to be paralleled in the same package based on the power level in the EV drive system. The bare dies for each TPAK can be purchased from different suppliers and allow cross-material platform use (Si IGBT, SiC MOSFET, GaN HEMT), establishing a diversified supply ecosystem.

China’s Deep Dive into SiC Module Design

In the vibrant Chinese market, automakers are accelerating the investment in SiC power modules, and are collaborating with domestic packaging factories and international IDMs to build technical barriers.

• Li Auto has collaborated with San’an Semiconductor to jointly establish a SiC power module packaging production line, expected to go into production in 2024. 
• NIO is developing its own motor inverters and has signed a long-term supply agreement with SiC device suppliers like ON Semi.
• Great Wall Motor, amidst its transformation, has also focused on SiC technology as a key strategy. Not only have they set up their own packaging production line, but they’ve also tied up with SiC substrate manufacturers by investing in Tongguang Semiconductor.

Clearly, the rising demand for SiC is redrawing the map of the value chain. We anticipate an increase in automakers and Tier 1 companies creating their unique SiC power modules tailored for 800-900V high-voltage platforms. This push will likely catalyze an influx of innovative product solutions by 2025, thereby unlocking significant market potential and ushering in a comprehensive era of EVs.

Chinese semiconductor companies are once again quickly making their presence known in the power semiconductor market, particularly in the fields of MOSFET, IGBT, and SiC.

Among various types of power ICs and power devices, MOSFET and IGBT-based voltage-controlled switching devices have become the mainstream products, accounting for more than 70% of power devices due to their ease of use, fast switching speed, and low power loss. They are mainly used in end markets such as automobiles, industry, and consumer electronics.

On the other hand, SiC can further assist in breakthroughs in EV technology and has become the most popular alternative technology route in the market, with its strong material properties such as low resistance, high temperature resistance, and high voltage resistance.

From IGBT and MOSFET to SiC, there has been a surge in demand in recent years, indicating the enormous growth potential of power semiconductors for automotive use. This has attracted many Chinese players to enter the competition.

IGBT: Explosive Growth for Chinese Players

As the core component of new energy vehicles, demand for IGBT is increasing. Looking at the financial reports of overseas large factories, the top five IGBT chip manufacturers in Q1 of this year still face tight delivery times, with the longest reaching 54 weeks.

The rapid growth of the EV and energy storage markets has resulted in a supply-demand imbalance for SiC MOSFETs. Major international IDM factories’ production capacity won’t be able to meet the demand in the coming years. Consequently, Infineon, STMicroelectronics, and ON Semiconductor are focusing on local supply in Europe and America. This has led to Chinese suppliers replacing automotive IGBTs for the domestic market.

In 2022, the IGBT industry in China saw a surge in demand. After a two-year auto chip shortage starting in 2020, the supply of IGBTs has become even tighter. In the second half of 2022, IGBT surpassed automotive MCU and became the biggest supply bottleneck affecting automotive production expansion.
According to the latest statistics from the China Association of Automobile Manufacturers, China’s new energy vehicles continued to explode in 2022, with production and sales reaching 7.058 million and 6.887 million vehicles, respectively, a year-on-year increase of 96.9% and 93.4%, maintaining the world’s first for eight consecutive years.

Many representative companies in China continue to strengthen their IGBT technology research and development:

• In the first half of 2022, StarPower Semiconductor developed a new generation of 650V/750V IGBT chips for the new car standard based on the seventh-generation microgroove Trench Field Stop technology, which passed customer verification and began mass production in the second half of 2022.
• Silan is keeping up with the trend of new energy development and has entered the field of vehicle-grade IGBT modules and SiC MOSFETs through a private placement financing. Its vehicle-grade IGBT and other products have been verified and have been delivered in bulk.

Since the end of 2021, the IGBT capacity of companies such as CRRC Times Electric, Silan, and Huahong Grace has been ready, and their revenue has also been rising. Combining the data of major companies with revenue exceeding 10 billion yuan that have released their 2022 financial reports, the power device companies are CRRC Times Electric, with 18.034 billion yuan, and Hua Run Micro, with 10.06 billion yuan.

MOSFET: Demand Doubles with the Rise of EVs

MOSFETs are used in high-voltage applications, such as DC-DC and OBC, to convert and transmit electrical energy. On average, there are now over 200 MOSFETs per car. As cars become more advanced and incorporate features like ADAS, safety, and entertainment, the number of MOSFETs per car is expected to double to 400 in high-end models.
With major companies such as Renesas gradually withdrawing from the low and medium-voltage MOSFET market, Chinese players have been accelerating their entry into the automotive supply chain. Currently, companies such as Silan and Nexperia are continuously expanding their global market share of MOSFETs, while other companies such as China Resources Microelectronics, Yangjie Electronic, Good-Ark Electronics, Jilin Sino-Microelectronics, NCE Power Co, New Jie Energy, Oriental Semi and Jiejie Microelectronics have been continuously developing in the field of automotive-grade MOSFETs in recent years.

Chinese IDM companies have expanded their market share by offering high-voltage super junction products:

• Silan has completed the development of a 12-inch high-voltage super junction MOS process platform.
• China Resources Microelectronics has achieved revenue of over 100 million yuan in the first quarter of 2022 for high-voltage super junction products.
• Yangjie Electronic has achieved a significant increase in MOS orders for automobiles in the first quarter of 2022.

SiC: Entire Supply Chain Enters the Game

The growth of EV and energy storage markets has been causing a supply shortage in SiC. As major international IDMs are expected to expand their SiC capacity and potentially engage in more M&A activities, Chinese manufacturers are simultaneously make more investments throughout SiC supply chain:

• IDM: Sanan Optoelectronics, Inventchip, Silan, and Sichain are trying to transform the IDM model by improving their processes but face development obstacles.
• Foundry: Besides Fabless manufacturers are participating in the SiC market, foundry companies such as X-FAB are also actively developing related businesses, especially Taiwanese manufacturers. After EPISIL Hong Young Semiconductor and ProAsia Semiconductor have also entered the market.

XinYueNeng a new foundry invested by Geely Auto, has also attracted market attention. Its related projects are expected to be put into operation in the second half of this year, and its partner AccoPower is already producing SiC power modules for vehicles.

It’s also important to note the development of the SiC specialized production equipment market. Some key equipment, such as the epitaxial reactor, is experiencing delivery delays, which may impact the expansion plans of suppliers like Tianyu Semiconductor and EpiWorld. On the positive side, it still presents great opportunities for local equipment manufacturers.

Read more:

• SiC vs. Silicon Debate: Will the Winner Take All?
• The M&A battle for SiC: Who’s the Top Acquirers?

The SiC market has been very active lately, with constant news coming from device suppliers and car makers. And there seems to be an ongoing tug-of-war between supply and demand.

Toshiba announced in April the groundbreaking of its power semiconductor fab for SiC in Ishikawa Prefecture, with the first stage beginning in the 2024 fiscal year. This news echoes earlier reports from Japanese media that Toshiba is strengthening the vertical integration throughout SiC equipment, wafers, and devices, and planning to increase the production by three times in 2024 and 10 times by 2026.

Meanwhile, over the past two years, leading companies in the Europe and the US such as Infineon and ST have also accelerated M&A as well as internal expansion for SiC production devices at an unprecedented pace, aiming to expand their SiC-related businesses and maintain their core competitiveness in the market.

Despite aggressive demand-driven expansion plans, the unexpected announcement from Tesla in mid-March that it plans to reduce overall SiC usage by 75% in the next generation of electric vehicle platforms has sparked various speculations in the industry. This move was made without compromising the performance and efficiency of the cars and represents one of the few specific details that Tesla has revealed about its new car plans.

Now here is the question – will the popularity of SiC be a genuine trend, or merely a passing fad that could lead to a potential bubble in the market?

SiC or Si-based solutions?

Compared to IGBT and MOSFET, the dominant technologies in power semiconductor, SiC offers stronger advantages such as low resistance, high temperature and high voltage tolerance that can overcome the technical bottlenecks of EVs by improving battery efficiency and solving component heat dissipation issues. SiC can also make chip design sizes smaller, which means more flexibility in vehicle design.

These advantages have made SiC the most sought-after technology. According to TrendForce, the SiC power device market is expected to grow at a CAGR of 35% to reach $5.33 billion annually from 2022 to 2026, driven by mainstream applications such as electric vehicles and renewable energy.

There is a long-standing debate among the industry about whether SiC will replace IGBTs entirely. What we believe is that SiC may not completely replace IGBTs considering their distinct targeted use scenarios.

In terms of use cases, SiC is particularly suitable for high-frequency, high-voltage applications, especially in the field of new energy vehicles. Traditional Si-based IGBT chips have reached the physical limit in high-voltage fast charging models, making SiC more favorable for new energy vehicles.

However, SiC transistors are expensive due to complex production processes, slow crystal growth, and difficult cutting. Unlike silicon, which can be pulled quickly, SiC crystals grow at a slow rate of 0.2-1mm/hour and are prone to cracking during the cutting process due to their high hardness and brittleness, leading to hundreds of hours of cutting time.

Additionally, SiC transistors also have some drawbacks such as vulnerability to damage and temperature sensitivity, which makes them unsuitable for low-cost and low-power applications.

IGBT, on the contrary, is preferred over SiC in such a field because it is more cost-effective, reliable, and has better capacitance and surge capability for high-power and high-current applications. In certain scenarios, such as DC-DC charging piles, IGBT is irreplaceable due to its cost advantage and suitability.

Could a Hybrid Solution be the Answer?

The premise above can help to explain Tesla’s conflicting decision to cut back on SiC usage.

Tesla’s reluctance to fully adopt SiC technology is mainly due to concerns about reliability and supply chain stability, as evidenced by a mass recall of Model 3 due to issues with SiC components in the rear electric motor inverter.

In addition, the shortage of substrate materials is another challenge facing the SiC industry as a whole, with major manufacturers such as Wolfspeed, Infineon, and ST ramping up production capacity to address the issue. As a result, Tesla is considering alternative ways to mitigate the risks associated with supply chain constraints.

Despite these challenges, SiC remains a promising trend for the EV industry. Even Tesla recognizes its enormous potential commercial value.

In terms of technological innovations, Tesla’s next-generation EVs may feature a novel packaging design for the primary inverter, utilizing a hybrid SiC/Si IGBT packaging approach that leverages the unique strengths of both technologies while avoiding potential pitfalls. This technological advancement poses certain difficulties, but the groundbreaking innovation at the engineering design level is definitely something to look forward to.

Read more:

• Chinese Players Rally for Demand Surge in MOSFET, IGBT, and SiC
• The M&A battle for SiC: Who’s the Top Acquirers?

(Photo credit: Tesla)