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[SMM topic] knowledge list of Silicon Industry chain
Sep 2,2020 15:02CST
The content below was translated by Tencent automatically for reference.

Silicon is a nonmetallic element that is a semiconductor material and the main raw material for solar cells. It can also be used to make semiconductor devices and integrated circuits. It is generally in the form of complex silicate or silica and widely exists in rocks, gravel and dust. The mined silica has to go through industrial silicon "polysilicon" monocrystalline silicon and refined step by step before it can be applied to the chip and photovoltaic industry. Related markets are mainly industrial silicon, monocrystalline silicon, polysilicon, silicon wafer, silicon wafer and other markets.

Resource distribution

International: although rich in resources, the distribution of silicon resources in the world is extremely uneven. According to records, Brazil is relatively rich, followed by Madagascar and Guatemala. More than 30 countries and regions, including Canada, Russia, the United States, France, Italy, India, Australia, Turkey and Myanmar, have a small amount of resources. Brazil ranks first in the world in terms of its total resources and its production and exports in recent decades. However, data in 2011 show that China has become the largest producer and consumer of the world's silicon industry.

Domestic: according to the data of Silicon Industry Branch, the output of polysilicon in the first half of 2020 was about 205300 tons, an increase of 33.1% over the same period last year. The increment of supply market in the first half of 2020 mainly comes from the 1GW production capacity of Yongxiang shares; in the second half of the year, domestic enterprises plan to increase production capacity as: Oriental Hope 30,000 tons and Poly Xiexin 20,000 tons, as South Korea OCI and Hanhua withdraw from the photovoltaic polysilicon market, the production capacity of other domestic enterprises are also being overhauled and withdrawn one after another.

At present, the layout of three major industrial bases in Xinjiang, Inner Mongolia and Sichuan has been formed in China, and the crystal pulling link of silicon wafers will also be gradually transferred to low electricity price areas such as Inner Mongolia, Sichuan and Yunnan.

Industrial application

1. Photovoltaic: monocrystalline silicon, polysilicon

A small amount of group IIIA elements are doped into monocrystalline silicon to form p-type silicon semiconductors, and a small amount of group VA elements are added to form n-type semiconductors. P-type semiconductors and n-type semiconductors combine to form a pmurn junction, which can be used to make solar cells that convert radiant energy into electricity. It is a promising material in the development of energy. Polysilicon is the direct raw material for the production of monocrystalline silicon, and it is the electronic information basic material for contemporary artificial intelligence, automatic control, information processing, photoelectric conversion and other semiconductor devices. It is called "the cornerstone of microelectronics building".

The production process of polysilicon is actually the purification process of silicon. Polysilicon material can be divided into electronic grade polysilicon material and photovoltaic grade polysilicon material. As the name implies, the former produces integrated circuits while the latter mainly produces photovoltaic materials. The difference between the two is that the purity of electronic grade and photovoltaic grade is different, and the two kinds of silicon materials are divided into one, two and three grades, and the purity of the third stage is the highest. Generally speaking, the purity of photovoltaic grade polysilicon is 6-11N, and that of electronic grade polysilicon is 9-12N N, which can be simply understood as the expression of purity. In terms of purity, the photovoltaic grade polysilicon material is lower than the electronic grade polysilicon material.

The photovoltaic industry chain is divided into upstream, middle and downstream.

The upstream industry is composed of polycrystalline / monocrystalline silicon, silicon wafer, silicon wafer and other raw materials.

The mid-stream industry is generally composed of single polycrystalline cells, crystalline silicon modules and thin film photovoltaic modules.

The downstream industry is generally composed of inverter, power station EPC system and operation.

Although the solar photovoltaic industry in China started late, it has developed rapidly, especially since 2013, driven by policy, solar photovoltaic power generation has shown explosive growth in our country. According to statistics from the National Energy Administration, China's newly installed photovoltaic power generation capacity reached a record high of 53.06GW in 2017. Under the influence of the Photovoltaic 531 New deal in 2018, new photovoltaic power generation projects around the country declined and continued to affect 2019. In the first half of 2020, new 11.52GW was installed in photovoltaic power generation across the country.

With the continuous development of the photovoltaic market, high-efficiency cells will gradually occupy the dominant position in the market. According to the forecast of China Photovoltaic Industry Association, the market share of single crystal silicon cells will gradually increase in the next few years. The market share of single crystal silicon wafers has exceeded 40% in 2018 and more than half in 2019, among which the market scale of N-type single crystal silicon wafers will also increase year by year.

At present, due to the overhaul and reduction of more than half of the production capacity of polysilicon enterprises, the price of silicon continues to rise. There are 11 enterprises producing polysilicon in China. Among them, four are undergoing maintenance, all of which are concentrated in Xinjiang. The silicon branch of the china non-ferrous industry association predicts that total silicon output is expected to fall by about 15% month-on-month in august. Among them, polysilicon production in Xinjiang is expected to decrease by 30% month-on-month, which is about 48% lower than the normal production in June.

two。 Chip semiconductors: monocrystalline silicon, silicon wafer, silicon wafer

High purity monocrystalline silicon is an important semiconductor material, and many parts of the world are named after "Silicon Valley". In addition, widely used diodes, transistors, thyristors, field effect transistors and various integrated circuits (including chips and CPU in people's computers) are all made of silicon.

According to the process, semiconductor wafers are divided into polished wafers, epitaxial wafers and SOI wafers. The polished wafer is obtained after the single crystal silicon ingot is cut, ground and polished. The polished wafer is epitaxially grown to form an epitaxial wafer, and the polished wafer is formed into SOI wafer after oxidation, bonding or ion implantation. SOI silicon wafer is mainly used in RF front-end chips of smart phones, WiFi and other wireless communication devices, as well as automotive electronics, power devices, sensors and other products.

Semiconductor silicon wafers are developing in the direction of large size. The sizes of semiconductor wafers are mainly 300mm (12 inches), 200mm (8 inches), 150mm (6 inches), 100mm (4 inches), 75mm (3 inches), 50mm (2 inches) and so on. With the continuous reduction of the semiconductor process, the chip production process is becoming more and more complex, the production cost is increasing, and the cost factor drives the silicon wafer to the direction of large size.

The semiconductor industry chain is divided into upstream, middle and downstream.

Upstream chip manufacturing closed test support industry, mainly semiconductor equipment and material providers, equipment representative manufacturers have ASML.

The mid-stream semiconductor manufacturing industry is divided into three parts: integrated circuit design, manufacturing and closed testing. IC designers include Huawei, Qualcomm, AMD and Nvidia.

Downstream semiconductor terminal applications include automotive electronics, industrial electronics, communications, consumer electronics, PC and other fields.

3. Smelting metal: ferrosilicon, industrial silicon

Silicon metal is widely used in metallurgy, chemical industry, electronics and other industries. In the metallurgical industry, it is mainly used as an additive for non-ferrous alloys. When silicon is added to some non-ferrous metals, it can improve the strength, hardness and wear resistance of the matrix metal, and sometimes enhance the castability and weldability of the matrix. Silicon is widely used in aluminum alloy and aluminum profile industry. Silicon metal is mainly used to produce silicon-based compounds in the chemical industry, such as silane, silicone, silicone, silicone oil and so on.

Ferrosilicon is a ferroalloy composed of iron and silicon. Ferrosilicon is an iron-silicon alloy made from coke, steel shavings, quartz (or silica) and smelted in an electric furnace. Because silicon and oxygen can be easily synthesized into silicon dioxide, ferrosilicon is often used as a deoxidizer in steelmaking. At the same time, because a large amount of heat is released during the formation of SiO2, it is beneficial to increase the temperature of molten steel at the same time of deoxidization. At the same time, ferrosilicon can also be used as alloy element additive, which is widely used in low alloy structural steel, spring steel, bearing steel, heat resistant steel and electrical silicon steel. Ferrosilicon is often used as reducing agent in ferroalloy production and chemical industry.

In addition, there are cermets and important materials for aerospace. Cermet composites are made by mixed sintering of ceramics and metals, which are resistant to high temperature, rich toughness and can be cut, which not only inherits the respective advantages of metals and ceramics, but also makes up for their congenital defects. It can be used in the manufacture of military weapons.

Optical fiber communication, the latest modern means of communication. Glass fibers with high transparency can be drawn from pure silica. The laser can be transmitted forward through numerous total reflections in the path of fiberglass, replacing the bulky cable. Optical fiber communication capacity is high, a glass fiber as thin as a hair can transmit 256 telephones at the same time, and it is not subject to electrical and magnetic interference, is not afraid of eavesdropping, and has a high degree of confidentiality. Optical fiber communication will revolutionize human life in the 21st century.

Silicone plastic is an excellent waterproof coating material. Spraying organosilicon on the four walls of the subway can solve the problem of water seepage once and for all. Coating a thin layer of silicone plastic on the appearance of ancient cultural relics and sculptures can prevent the growth of moss and resist wind and rain and weathering.

Current situation of foreign trade

In the downstream demand of China's industrial silicon, exports account for a very important part, accounting for about 30%, but because Western countries implement anti-dumping against China, the efficiency of China's industrial silicon export is low; secondly, aluminum alloy, organosilicon and polysilicon are the main downstream applications of industrial silicon in China.

With the continuous improvement of the quality of silicon materials and the continuous decline in prices of the leading domestic enterprises, the supply of imported silicon materials has dropped sharply since the second quarter of 2020, with the market share falling below 20%. The market share of China's silicon material imports is 30% in 2019. It is expected that the proportion of decline in the imported silicon market for the whole of 2020 will be even greater. According to the production and operation plans of overseas silicon enterprises, the Silicon Industry Branch expects polysilicon imports in the first half of 2020 to be about 55000 tons, and the total imports in the second half of the year may be less than 40, 000 tons, and the monthly imports are about 6500 tons.

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