Forecast and analysis of the development status and market prospect of silicon carbide device industry in China in the future

①Silicon carbide devices have obvious advantages, is the next generation of power semiconductor development direction
Looking back on the development history of power semiconductor, new power devices have been born with the development of technology. In 1957, general electric developed the world's first thyristor, which started the prelude of the development of power semiconductor industry. The sixties and seventies were the heyday of thyristor power devices. Thyristor and MOSFET together dominated the power device market in the 1980s. In the 1990s, thyristor gradually gave way to MOSFET and IGBT, small and medium power applications MOSFET began to dominate the market, IGBT dominated medium and high power applications.

Silicon carbide and gallium nitride are the core technologies of the next generation of power semiconductors. The efficiency and power density of silicon carbide devices are much higher than the current market mainstream products. Due to cost factors, market penetration of silicon carbide power devices is less than 1%. We judge that technological progress will drive silicon carbide cost down rapidly, and silicon carbide devices will be the mainstream products in power semiconductor market in the medium and long term.
Advantages of silicon carbide over silicon devices
Compared with silicon-d devices, silicon carbide devices have the characteristics of high voltage resistance, low loss and high efficiency and are ideal power management elements.
High working frequency: silicon-d IGBT usually works at the frequency of 20Khz, while silicon-d MOSFET can still maintain high efficiency at the frequency of 100Khz.
High tolerance temperature: silicon carbide d devices can withstand higher operating temperature, silicon IGBT at most 150-200 degrees, and silicon carbide d MOSFET at 200-250 degrees can still work normally.
High efficiency: switching loss and conduction loss of silicon carbide devices are greatly reduced. Switching losses are typically 15-30% of those of silicon devices, greatly increasing energy efficiency.
To sum up, silicon carbide has two core advantages. One is that the switching loss is small and the conduction loss is small, so the energy utilization efficiency is much higher than that of silicon devices. The loss is only 15%-30% of the same silicon devices. Second, the module size is small. Since silicon carbide chips can work at higher frequencies, the size of the supporting peripheral capacitor inductance is greatly reduced, and the size of silicon carbide modules is often only 1/5 of that of silicon device modules.

Comparison of key electronic parameters between silicon and third generation semiconductor materials

 At present, silicon carbide devices are mainly used in the application fields of 600v and above, especially some applications requiring higher energy efficiency and space size, such as electric vehicle charging device, electric vehicle power assembly, photovoltaic micro-inverter and other applications.

Milestones in silicon carbide transition

   ②Silicon carbide weighs medium to high power, gallium nitride weighs medium to low power

   Silicon carbide and gallium nitride are slightly different in application fields. The advantageous application fields of silicon carbide are concentrated in medium and high power applications, while gallium nitride is concentrated in medium and low power applications.

③Silicon carbide costs continue to fall, permeability will continue to increase

    In 2012, the cost of silicon carbide diode was 5-7 times higher than that of silicon-d schottky diode, and the cost of silicon carbide MOSFET was 10-15 times higher than that of silicon-d MOSFET. Over the course of three years, the price of silicon carbide diodes fell 35 percent, and the price of silicon carbide MOSFET fell 50 percent.
We believe that the cost of silicon carbide will continue to decline, driven by the cost of the following factors.

    （1）The process of moving from 4-inch line to 6-inch line reduces the cost by 20-40%.

    （2）Silicon carbide epitaxial wafer technology continues to progress, particle pollution and other defects rate in the continuous decline, promote the chip yield significantly increased.

    （3）With the expansion of scale and the accumulation of experience, silicon carbide chip manufacturing process technology is becoming more and more mature, and the yield of manufacturing continues to improve

   At present, the cost of silicon carbide and gallium nitride products is relatively high. Overall, silicon carbide device yield and silicon process has a significant gap.

  ④Automotive applications will push silicon carbide permeability up rapidly

In the field of automotive applications, silicon carbide devices replace silicon devices is a certain development trend. Applications of silicon carbide power devices continue to expand. In the early stage, silicon carbide was mainly used in power correction circuit. Currently, its mass production application has been extended to photovoltaic inverter and onboardcharger. It is expected that from 2019 to 2020, the electric vehicle power system will be introduced into silicon carbide power devices, further expanding the field of mass production applications.
At present, tier-1 automobile supply chain enterprises are trying to import silicon carbide and actively carry out the testing of silicon carbide power devices. Toyota started the full-vehicle test of silicon carbide power devices in February 2015, and the road test prototype car was equipped with silicon carbide power devices in PCU booster converter and motor control inverter. According to the investigation, byd has introduced silicon carbide power components into the onboard chargeronboard of electric vehicles.
The BOM cost of silicon carbide power system is only 60% higher than that of silicon-d power system. We believe that with the further reduction of silicon carbide cost, large-scale replacement of silicon-d power devices is imperative. When silicon carbide/gallium nitride operates at higher switching frequencies, the required peripheral electronic components and cooling system costs are significantly reduced. Although in terms of cost per device, silicon carbide/gallium nitride is more than 5 times more expensive than silicon-d devices. However, in terms of the overall cost of the system, the cost gap between silicon carbide/gallium nitride and silicon-d devices is very small. According to the data, the BOM cost of a single 60kw silicon carbide power module is $732, while the BOM cost of the corresponding silicon-d IGBT power module is about $458. The cost of silicon carbide power system is only 60% higher than that of the silicon-d power system.

 ⑤The domestic industrial chain is taking shape

    Silicon carbide industrial chain can be divided into three industrial s, one is the upstream substrate, two is the middle epitaxial wafer, three is the downstream device manufacturing. Foreign supply chain system mainly includes:
Substrate: Cree, Rohm, EPISIL
EPI epitaxial plate: Cree, Rohm, infineon, GE, mitsubishi
Devices: infineon, Cree, Rohm, stmicroelectronics, micron, GenSiC, mitsubishi
Silicon carbide devices, the international silicon carbide SBD, silicon carbide MOSFET have achieved mass production, the product pressure range of 600v-1700v, single chip current more than 50A.
A relatively complete silicon carbide industrial chain system has been formed in China.
Substrate material: shandong tianyue, tianke heda, hebei tongguang crystal, Beijing century golden light
EPI silicon wafer: dongguan tianyu semiconductor, xiamen hantiantian
Devices: tyco tianrun, hanxin, yangjie technology, CLP 55, CLP 13, keneng core, CRRC era electric
Module: jiaxing sida, he nansen yuan, changzhou wujin kehua, zhongche era electric
At present, silicon carbide market is in the initial stage, the gap between domestic manufacturers and overseas traditional giants is small, and domestic enterprises are expected to overtake in the local market applications. Domestic enterprises have formed sales revenue in silicon carbide SBD, and the industrialization of silicon carbide MOSFET is still in the prototype device development stage. In addition, China has developed 1700V/1200A hybrid module (silicon IGBT mixed with silicon carbide SBD), 4500V/50A and other large capacity full SiC power modules.