Market opportunities and challenges of SiC Power Devices

With the development of intelligent, networked and electric vehicles and 5g commercial application, the third generation semiconductor materials silicon carbide (SIC) and gallium nitride (GAN) will be developed. According to the estimation of Tuolong Industry Research Institute, the global output value of SiC substrate will reach 180 million US dollars in 2018, while the output value of GaN substrate is only about 3 million US dollars.

The third generation semiconductor has the characteristics of high breakdown electric field, high saturated electron speed, high thermal conductivity, high electron density, high mobility, etc., so it is also known as the "core" of solid-state light source, power electronics, microwave RF devices, as well as the "new engine" of Optoelectronics and microelectronics industries. The good development of wide band gap semiconductors are mainly SiC and Gan, among which the development of SiC is earlier.

SiC power devices and electric vehicles

Silicon carbide (SIC) single crystal materials have many properties, such as wide band gap (3 times of Si), high thermal conductivity (3.3 times of Si or 10 times of GaAs), high electron saturation migration rate (2.5 times of Si) and high breakdown electric field (10 times of Si or 5 times of GaAs).

SiC devices have irreplaceable advantages in the fields of high temperature, high voltage, high frequency, high power electronic devices, aerospace, military industry, nuclear energy and other extreme environmental applications, which make up for the defects of traditional semiconductor devices in practical applications, and are gradually becoming the mainstream of power semiconductor. They are used in the field of power electronics and can realize the conversion and control of power in the system. It is also suitable for high voltage applications, such as power supplies, solar inverters, trains and wind turbines. In addition, SiC is also used to make LEDs.

In the next 5 to 10 years, the growth opportunities of SiC power device market are mainly in the automotive field, especially in the EV, hybrid vehicle, fuel cell vehicle and other electric vehicle application markets. Its application rate depends on the location of SiC, such as the main inverter, on-board charger (OBC) or DC / DC converter.

Industrial trends of SiC Power Devices

For example, the SiC based power semiconductor is used in the vehicle charging device of electric vehicle, and this technology is entering the key part of the system - traction inverter. The traction inverter provides traction for the motor to drive the vehicle forward.

For this application, Tesla uses SiC Power Devices in some models, while other electric vehicle manufacturers are evaluating the technology. "When people talk about SiC power devices, the automotive market is definitely the focus," said Hong Lin, an analyst at yole D é velopment. The SiC activities of pioneers such as Toyota and Tesla have brought a lot of excitement and noise to the market. SiC MOSFET has potential in the automotive market. But there are still challenges, such as cost, long-term reliability and modular design. "

BYD in China also announced their SiC layout recently. At present, the company has invested heavily in the layout of the third generation semiconductor material SiC, and will integrate the whole industrial chain of SiC Based semiconductors such as materials (high-purity silicon carbide powder), single crystals, epitaxy, chips, packaging, etc., to reduce the manufacturing cost of SiC devices and accelerate its application in the field of electric vehicles.

They have successfully developed SiC MOSFET (automobile power semiconductor includes IGBT or MOSFET based on silicon or silicon carbide and other materials), and are expected to launch electric vehicle with SiC electric control in 2019. BYD is expected to replace the silicon-based IGBT with SiC based power semiconductor in its electric vehicles by 2023, and improve the performance of the whole vehicle by another 10% on the existing basis.

According to yole, driven by automobile and other markets, the SiC power device business reached US $302 million in 2017, up 22% from US $248 million in 2016. "Driven by the automotive industry, we expect to see a leap forward in 2018 due to the growth of Tesla Model 3 capacity with SiC MOSFET modules," Lin said

According to yole, the SiC Power semiconductor market is expected to reach $1.5 billion by 2023. The suppliers of SiC devices include Fuji, Infineon, Littelfuse, Mitsubishi, Anson semiconductor, Italian French semiconductor, Rohm, Toshiba and wolfspeed. Wolfspeed is part of Cree. X-fab is the only OEM of SiC.

Infineon converts all SiC manufacturing lines to 6-inch SiC wafers. At the same time, we have reached a strategic long-term supply agreement with Kerui for silicon carbide (SIC) wafers, through which Infineon can expand the supply of SiC products to meet the high growth market demand such as photovoltaic converters and electric vehicles; Infineon has converted all SiC products to 6-inch manufacturing line production, so the agreement with Kerui only covers the size of such wafers.

X-FAB plans to double its 6 inch SiC process capacity in La Burke, Dezhou, USA. X-fab is believed to be the first wafer foundry to offer SiC technology on 6-inch wafers. For this reason, the company purchased a second heated ion implanter, which will be delivered at the end of this year, and will start production in the first quarter of next year (in time to meet recent demand expectations). This expansion also shows its commitment to SiC technology and OEM business model.

The third generation SiC MOSFET with groove structure has been developed by Rom. compared with the second generation plane structure, the device realizes the on resistance of lower resistance and reduces the power loss of all devices. In response to the shortage of products, it is reported that Roma is building new factories and production lines, and the capacity of 2025 is expected to be 16 times of that of 2017.

Challenges in the development of SiC Power Devices

In technology, SiC has the advantages of high efficiency and high power density, but the cost is high. Compared with the previous Si devices, the balance between performance and cost of SiC power devices and the demand for high technology will become the key to the real popularization of SiC power devices. For example, the microtubule defect density and epitaxial process efficiency of silicon carbide wafer are low