One article understands IGBT
Technical Blogs|Technical Blogs|
2022-03-17 18:38:24
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1、What is IGBT?
The full name of IGBT is insulated gate bipolar transistor, which is a compound structure device. It combines the advantages of MOS transistor and BJT bipolar transistor. It is widely used in the fields of voltage-current conversion and power output, especially in the high-voltage and high-current fields. IGBT is one of the core semiconductor devices for human beings to control and utilize power. This semiconductor device is mainly used in the field of electronic power conversion, and we collectively call it power semiconductor. The simplest applications, such as our notebook computers, are equipped with power adapters, which are IGBT, which plays a role in the process of voltage increase and decrease and AC/DC change. Obviously, IGBT is the most important member of power semiconductors. Its function is to control electricity, and it is the core chip of electric energy conversion and application. Is IGBT a customized product or a general product? Compared with other chips, IGBT is a standard product. Usually, a detailed introduction of IGBT products will be released in official website of various companies, and various parameters of this IGBT product will be stated, such as maximum collector current ICM, maximum emitter voltage UCES, gate breakdown voltage UGEM, conduction voltage, withstand voltage level, switching speed, carrier type and life, input capacitance, maximum collector power consumption PCM, operating temperature range, etc. After seeing these parameters, customers can design and match them according to actual application requirements. According to different application scenarios and different customers, there will be various adjustments. Once finalized, it is unlikely to be replaced, but if the supply is not available, it is also possible to change a similar product from another company. But in essence, we still think IGBT is a standard universal product. Why is IGBT regarded as the most beneficial power semiconductor for carbon neutrality? With the large-scale promotion of clean energy, higher demand is put forward for IGBT, and the most typical one is the application of photovoltaic inverter, which requires a large number of high-voltage and ultra-high-voltage IGBT and IGBT modules, so that the coarse electricity emitted by photovoltaic can be turned into fine electricity that can be smoothly connected to the Internet. Therefore, this is a very important link of carbon neutrality in the future. In the application of IGBT in the era of electric vehicles, in the past, cars were all fuel-powered vehicles, and no matter how the gasoline was changed, the exhaust emission of gasoline vehicles could not be changed. However, energy-saving and environment-friendly new energy vehicles are advocated now, and the future will be the era of new energy electric vehicles, and electric vehicles need a large number of power semiconductor products such as IGBT. The acquisition and utilization of clean electric energy is the key to reduce carbon dioxide emissions and achieve carbon neutrality in the future, and the utilization of electric energy is inseparable from power semiconductors and IGBT. What are the fields of downstream applications? How big is the industry space? Because semiconductor is a basic industry, all fields related to electricity are where power semiconductors play their part, so this industry is very big, because at least 50% of products around us are related to electricity and electronic products, such as consumer electronic phones, Bluetooth headsets, notebook computers, various household appliances, as well as large industrial motors, rail transit, new energy vehicles, photovoltaic inverters, smart grids, etc., where electricity is needed, IGBT is basically indispensable. As far as the industry scale is concerned, the global market for IGBT and modules exceeded USD 7 billion in 2019, and this year it will exceed USD 10 billion. It is predicted that it will reach USD 19 billion by 2026, with a compound annual growth rate of about 15%. It belongs to a relatively fast-growing market, and it is a relatively stable growth segment. Unlike other products, such as memory, which have ups and downs and obvious cycle changes, IGBT belongs to a steady growth type. With the new energy electric vehicles and the electronic electrification of various industries, and the use of clean energy, the power semiconductor field, including IGBT, continues to maintain a strong and powerful growth. Usually, we divide the voltage according to IGBT into different grades. The voltage below 650V-900V is medium and low voltage, the voltage above 900-1200V is medium and high voltage, and the voltage above 1200V is high voltage. IGBT below 650V is also available, but the usage is not large. MOSFET products are more used in this field. Among them, most consumer electronics, white goods, etc. belong to the range of low-voltage IGBT, which accounts for about 30%. High-voltage IGBT accounts for 20% in high-power industrial fields. IGBT used in high-voltage and high-power energy fields, such as high-speed rail, photovoltaic inverter and rail transit, accounts for 15%. In addition, new energy vehicles in the field of automotive electronics account for more than 30%, and this is the most promising track in the future. What is the supply and demand situation of the market? It is expected that supply and demand will be balanced in a few years. At present, the whole semiconductor out-of-stock market has been going on for more than a year. From July 2020, the semiconductor products began to show different degrees of tension, and after October, it broke out in an all-round way, and the prices soared, reaching the peak at the end of May this year. The price increase of many chips is very exaggerated, and the wafer factory is constantly adjusting the prices. Even so, it is still crazy to place orders, and the frantic rush for chips in the downstream leads to the looting of the upstream production capacity, which leads to a complete imbalance between supply and demand in the whole industry. Many people in the industry have made various predictions and assumptions for the semiconductor industry to restore the balance between supply and demand and return to normal state, and predicted various time nodes for returning to normal, as well as the preconditions for the formation of inflection points. My personal opinion is that around June 2022, first of all, let's look at various factors that affect the relationship between supply and demand. Judging from the historical experience to judge the changes of the industry, generally speaking, the semiconductor boom period is 24-36 months, and the cold period is 12-18 months. Since June last year, we think it is the beginning of the boom period, so this boom period will last until June 2022. Considering the influencing factors of the epidemic, although the epidemic has disrupted the rhythm of the global industry, it should be a new opportunity and a new challenge for semiconductors, especially for China. At least, we think that there have been two huge explosion points in these two years. The first is to work at home after the epidemic. Online work has led to a surge in demand for various tablet laptops, which has boosted the demand for semiconductor chips, because 90% of the cost of these products is semiconductor devices. Therefore, this surge has been caused. After each epidemic, it is the golden period of automobile sales. Just now, the concept and cycle of new energy vehicles have been superimposed. The content of semiconductor products in the whole vehicle has been greatly increased, while that of traditional fuel vehicles is only about 10-15%. However, the semiconductor products in new energy vehicles account for more than 50%. The most important parts of this piece are various automotive electronics, automotive power semiconductors, sensors, various micro-control units MCU, etc. What these chips have in common is that quite a number of products are manufactured by 8-inch 0.25-0.13 process. However, it is difficult to expand the production capacity of 8-inch line because of equipment problems, so the continued strong demand for these products may continue the shortage of chips. However, too high a price will also reduce the downstream demand, so my conclusion is that under normal circumstances, it will last until June 2022. I think this time point is the turning point, after which the shortage of chips will ease and inventory will begin. This is my personal judgment, and I don't even rule out that this node will come ahead of time. Now, China's extensive power outage and production restriction will squeeze out the downstream inflated demand and keep the chip gap shrinking. From this perspective, For a period of time, the price and demand of chips will definitely fall, so I think this extreme imbalance will last for another 6-9 months at most, and it will definitely recover, with the exception of automotive electronics, of course. This industry is too special, and there are too many factors influencing the restoration of the industrial chain. How big is the impact of overseas epidemic on IGBT production capacity? When is it expected to be relieved? The overseas epidemic situation has a great impact on several established semiconductor companies, such as Infineon, Ansenmei, etc., and the supply is very unstable. As for when it will be relieved, it is difficult to judge. At least, I don't think it is likely to be relieved until June next year, and it may face an inflection point after June. The goods of these big factories have always been in short supply, whether it is now or not. Judging from the situation in previous years, there will always be a time period in a year when the supply is not smooth, leading to price increases, but they are mainly concentrated on high-end products. Now, the domestic substitution pace of low-end IGBT products is relatively fast, and it will definitely ease after the release of future production capacity. At present, domestic medium and low-voltage products are very mature, and their cost performance is very high, but there is still a certain gap between high-end high-voltage products and foreign countries. I think this gap is mainly reflected in how to keep the consistency and stability of products during mass production. It is not that China is incapable of doing it, but that the quality of medium and low-voltage products cannot be controlled when they are in high quantity. The good domestic substitution momentum has already explained everything.
What is the difference between IGBT used in new energy vehicles, photovoltaics and energy storage? What functions are they used for? At present, the new energy used by automobiles is mainly between 650-900V, and a few automobile companies also have 1200V schemes, among which OBC uses 650V single tube, and PCU uses 900V IGBT modules. It depends on the battery pack schemes and voltage of each automobile manufacturer, and then choose what type of IGBT to use. Very different. IGBT module, mainly IGBT, and then some other power semiconductor devices such as FRD (Fast Recovery), TVS (Instantaneous Voltage), SBD, etc. are needed to form a module to cope with various scenarios and demands. If it is an IGBT IPM module, the internal power control IC is integrated, and there are power management IC besides IGBT and other power semiconductor products. 8、What is the proportion of IGBT in the cost of new energy vehicle/photovoltaic/energy storage? PCU+OBC, a new energy vehicle, accounts for at least 25%-30% of the whole vehicle, and the cost ratio of different models is very different. For example, such a magic car as Wuling mini sells for 2.98 yuan in total, and the cost of electronic control will not exceed 3,000 yuan. This kind of car doesn't even need IGBT, it's all MOSFET, and for example, the Great Wall Euler Black Cat sells for 60,000 or 70,000 yuan per car, and the cost of a battery pack is 15,000 yuan, and the IGBT can be used. The consumption and price of IGBT in high-end cars are large, and IGBT is also used as inverter for photovoltaic and energy storage. This cost proportion is hard to say, because the bulk of a power station is in perc batteries and other structures, depending on the investment scale. 9、Will there be IGBT capacity grabbing among different industries? It's the status quo of the whole industry, and now it means that whoever has money can grab the production capacity. Large companies have an advantage, because of the large amount of money. At present, a considerable proportion of domestic power semiconductors are IDM models. For example, Silanwei and Shidai Electric have their own production lines, so there is no such thing as grabbing the production capacity. Other companies that can do IGBT OEM work are Hua Hong, and this production capacity depends on grabbing. Some companies with deep pockets, such as Starr, have already rounded up a line of others. 10、Will IGBT have customized requirements for production lines? What is the main difference? The process of IGBT is quite different from that of common logic products, at least the ion implantation doping process and the back subtraction process are definitely different, and there are various special epitaxial layer processes and so on. These are completely different from ordinary digital circuits and analog circuits. 11、Can the IGBT production line temporarily adjust the product specifications, for example, the IGBT production line used for photovoltaic production is temporarily adjusted to the car gauge grade IGBT production line? The requirements of car grade are relatively high, and once finalized, it is impossible to easily replace them. Although they are all IGBT's, because they are in different sub-industries, they have completely different requirements for IGBT's, and there is no possibility of mixing them. However, since it is all produced by one company, different IGBT's capacity is distributed on the production line, which is a matter within the company itself. The equipment is still this set of equipment, and the production line is still this set of production lines. There are certain differences in packaging, so we can only say that. At the same time, customers are not happy to mix product lines with other products, so IGBT wires for automobiles are unique. 12、Is there a big difference between the certification time of vehicle gauge grade and photovoltaic IGBT production line? Different from the very high requirements of the gauge, the factory inspection requirements of the whole vehicle factory are extremely strict. Not only the suppliers, but also the suppliers' suppliers, suppliers' raw material suppliers, etc., the PV product line is relatively simple, and the difference is big. 13、 What is the biggest pain point of expanding new capacity? As far as the process difficulty is concerned, IGBT can basically use 8-inch process, and a few industry companies have started to introduce 12-inch. Now, building new production capacity does not mean expanding production when you have money. The biggest problem of 8-inch is the lack of equipment, and the price is higher. For example, the price of 8-inch equipment is almost the same as that of 12-inch, and the delivery cycle is long, as well as the talent gap that has been plaguing China's semiconductor industry. To sum up, it is mainly the lack of equipment and experienced people.
Summary: IGBT is the core chip of electric energy conversion and application, and it is a very important component of carbon neutrality. Its largest downstream application is in the field of new energy vehicles, and it is the second largest cost after batteries. In addition, the inverter used in photovoltaic has a large demand for IGBT. At present, the supply and demand of IGBT market is seriously unbalanced, and the overseas epidemic situation leads to the limited production capacity of large factories. The main reason for the difficulty of domestic manufacturers in expanding production lies in the lack of equipment and experienced professionals. On the other hand, it usually takes 1-3 years for new factories to land on the production line for verification, so it takes time for new production capacity to be released. Experts predict that the time when supply and demand will be balanced again in June 2022.
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