Benefiting from the increased demand in electric vehicles, 5g infrastructure and other fields, SiC (silicon carbide) power components are steadily penetrating the global market. According to the statistics of professional organizations, in 2018, more than 20 automobile manufacturers in the world used SiC Schottky diodes or sic MOSFET and SiC Power semiconductor are also expected to be CAGR in OBC market in the future 44% to 2023.
It is understood that in addition to Tesla's latest model & nbsp; SiC is adopted for model 3 In addition to MOSFET to improve the working efficiency and charging efficiency of electric drive system, 350kW super charging stations in Europe are also increasing the use of SiC devices. In China, BYD, BAIC new energy and other auto enterprises are also adding the application of SiC devices in the field of electric vehicles, mainly in the scene of automobile charging pile.
The rise of the third generation semiconductor materials
Science and technology are always progressing. The development of semiconductor materials has gone through three stages:
The first generation semiconductors are called "Elemental semiconductors", typically silicon-based and germanium based semiconductors. Among them, silicon-based semiconductor technology is widely used and mature. Up to now, more than 99% of semiconductor chips and devices in the world are produced based on silicon chips.
In 1950, the semiconductor material was dominated by germanium, which was mainly used in low-voltage, low-frequency and medium power transistors, but its disadvantage was also very obvious, that is, its high-temperature resistance and radiation resistance were poor.
By 1960, the emergence of 0.75 inch (20mm) monocrystalline silicon chip made the shortcomings of germanium based semiconductor infinitely amplified. At the same time, silicon-based semiconductor completely replaced the market of germanium based semiconductor.
After entering the 21st century, the rapid development of communication technology has made GaAs (gallium arsenide), InP (indium phosphide) and other semiconductor materials a new market demand. This is also the second generation of semiconductor materials, which is called "compound semiconductor".
Due to the higher requirements for the use conditions of electronic devices and the need to adapt to the environment of high frequency, high power, high temperature resistance and radiation resistance, the third generation wide band gap semiconductor materials have ushered in new development.
Of course, the third generation semiconductor materials are also compound semiconductors, mainly including SiC, Gan, etc. as for why they are called wide band gap semiconductor materials, it is mainly because their band gap width is greater than or less than 2.3ev (electron volts).
At the same time, because the third generation semiconductor has the characteristics of high breakdown electric field, high saturated electron velocity, high thermal conductivity, high electron density and high mobility, it is also known as the "core" of solid-state light source, power electronics and microwave RF devices, as well as the "new engine" of Optoelectronics and microelectronics.
Opportunities brought by new energy vehicles to SiC
Although they are the third generation semiconductor materials, the application scenarios are also different due to the different properties of SiC and Gan< br/>
The market application of Gan is biased towards the field of high-frequency and small power, which is concentrated below 1000V; SiC is suitable for 1200V In the above high-temperature and large power fields, their application fields cover most emerging application markets with broad development prospects, such as new energy vehicles, photovoltaic, locomotive traction, smart grid, energy-saving household appliances, communication RF and so on.
Compared with Gan, the thermal conductivity of SiC is more than three times that of Gan, which has more advantages in high temperature applications; At the same time, the preparation technology of SiC single crystal is relatively more mature, so SiC There are more kinds of power devices than Gan& nbsp;
SiC Power electronic devices mainly include power diodes and triodes (transistors, switches). SiC power devices can multiply the power, temperature, frequency, radiation resistance, efficiency and reliability of power electronic system, and greatly reduce the volume, weight and cost. The application fields of SiC power devices can be divided by voltage:
Low voltage applications (600 V to 1.2KV): high-end consumer fields (such as game consoles, plasma and LCD TVs), commercial applications (such as laptops, solid-state lighting, electronic ballasts, etc.) and other fields (such as medical treatment, telecommunications, national defense, etc.);
Medium voltage applications (1.2KV to 1.7kv): electric vehicle / hybrid electric vehicle (EV / HEV), solar photovoltaic inverter, uninterruptible power supply (UPS) and industrial motor drive (AC drive) (1) etc;
High voltage applications (above 2.5KV, 3.3kV, 4.5kv and 6.5kv): wind power generation, locomotive traction, high voltage / UHV power transmission and transformation, etc.
Diodes, MOSFETs, IGBTs and other devices made of SiC are expected to replace Si in the field of automotive electronics in the future. Compared with the current mainstream 1200V For silicon-based IGBT and SiC MOSFET, it can be found that SiC MOSFET products can significantly reduce die compared with Si based products Size and better performance. However, at present, the biggest obstacle still lies in the cost. According to yole development, the cost of single SiC is 7-8 times higher than that of Si based products.
The industrialization of SiC has accelerated recently, and the upstream industrial chain has begun to expand its scale and lock in the supply of goods. Sorting out the global SiC manufacturing leader Cree announcement, it is found that the recent progress of silicon carbide industrialization has begun to accelerate, and midstream manufacturers such as st and Infineon have begun to lock in the upstream.
In February 2018, Cree signed a US $100 million long-term supply agreement with Infineon to provide photovoltaic inverters, robots, charging infrastructure, industrial power supply, traction and variable speed drives SiC wafer.
In October 2018, Cree announced a $85 million long-term agreement to produce and supply SiC for an unnamed "leading power equipment company" Wafers.
In January 2019, Cree signed a multi-year US $250 million production and supply agreement with ST, and wolfspeed will supply 150 mm to St SiC wafer.
According to the prediction of IHS, the market scale of SiC Power semiconductor is expected to reach US $3 billion by 2025. In the next 10 years, SiC Devices will begin to be widely used in industry and electric vehicles. The main driver of this market growth is due to the increasing use of SiC devices in power supply and inverter applications.
We know that vehicle power module (IGBT is the mainstream at present) determines the key performance of vehicle electric drive system. At the same time, it accounts for more than 40% of the cost of motor inverter and is the core component< br/>
At present, IGBT accounts for about one third of the cost of motor driver, and motor driver accounts for about 15 ~ 20% of the cost of the whole vehicle, that is, IGBT accounts for 5 ~ 7% of the cost of the whole vehicle. In 2018, if the sales volume of new energy vehicles in China is calculated as 1.25 million, the average consumption of IGBT per vehicle is about $450, and all vehicles need to consume about $560 million of IGBT.
However, the emergence of SiC has enabled people in the industry to seize new opportunities. Some even believe that SiC will completely replace IGBT in the future. So, why does the market favor SiC so much?
The editor sorted out the views of some operators and summarized the following three points:
1. The operating junction temperature of SiC devices is above 200 ℃, the operating frequency is above 100kHz, and the withstand voltage can reach 20kV. These properties are better than those of traditional silicon devices;
2. The volume of SiC device can be reduced to 1 / 3-1 / 5 of the whole IGBT, and the weight can be reduced to 40-60%;
3. SiC devices can also improve the efficiency of the system and further improve the cost performance and reliability.
Under different working conditions of electric vehicles, the performance comparison between SiC devices and IGBT is shown in the figure below. Under different working conditions, the power consumption of SiC is reduced by 60-80% and the efficiency is increased by 1-3%. The advantages of SiC can be seen.
Photo source: PSIC 2019 Forum
On the whole, if SiC wants to replace IGBT, it also needs to solve many problems such as yield, cost and reliability. In other words, if SiC is not as cost-effective as IGBT, it is unlikely to replace it.
Of course, the future prospect of SiC can be expected. After all, its overall performance is much higher than IGBT. If it is used in new energy vehicles on a large scale, it will greatly improve its charging efficiency, mileage and reduce the weight of the whole vehicle (the most obvious example is Tesla Model 3). As for the replacement of IGBT, it is only a matter of time. The current market situation is that SiC will gradually replace some of the markets of IGBT in the field of new energy vehicles, and this trend will gradually increase with the large-scale mass production of SiC.
What are the difficulties faced by SiC large-scale commercial
From the perspective of industrial chain, silicon carbide includes single crystal substrate, epitaxial wafer, device design, device manufacturing and other links, but at present, the global silicon carbide market is basically monopolized by foreign enterprises
In the global market, single crystal substrate enterprises mainly include Cree, dowcorning, sicrystal, II-VI, Nippon Steel, Sumitomo and norstel, while epitaxial wafer enterprises mainly include dowcorning, II-VI, norstel, Cree, Roma, Mitsubishi Electric, Infineon, etc. in terms of devices, most of the global market share is divided by Infineon, Cree, Roma, Italian French semiconductor and other enterprises.
Due to the strong correlation between silicon carbide industrial links such as chip performance and materials, structural design and manufacturing process, many enterprises still choose to adopt IDM mode. For example, Roma and Cree cover the whole industrial chain of silicon carbide substrate, epitaxial wafer, device and module. Cree accounts for about 40% of the substrate market and 23% of the device market.
In fact, at present, the whole silicon carbide industry has not yet entered the mature stage, but international manufacturers have made breakthroughs in the technical bottleneck of large-scale mass production in many links, and have been gearing up for a world war. However, the domestic silicon carbide industry is still in its infancy and there is still a gap with the international level.
Source: yole development, Guosheng Securities Research Institute
At present, the challenges faced by SiC chips mainly include:
1. Low yield and high cost. SiC is superior to IGBT in efficiency, but the manufacturing cost is high, because SiC has inconsistency in material stress in epitaxial fabrication
皖公网安备 34020302000234号Sitemap