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Independent production is about to realize the production of 5000 tons of electronic silicon production line

silicon is a ubiquitous element, with a content of 26.3% in the earth's crust (second only to oxygen), but high-purity silicon is a strategic level of advanced basic materials, with many unique properties, in line with the unique requirements of photovoltaic industry and semiconductor industry for components

the resistivity of silicon is closely related to temperature. With the increase of temperature, the resistivity will obviously decrease, reaching the minimum at about 1480 ℃. In other words, in normal use, the higher the temperature, the stronger the conductivity, which gives photovoltaic and semiconductor devices more convenience

pure semiconductor materials have high resistivity, but their conductivity will be significantly improved after adding a very small amount of impurity elements

therefore, people have very high requirements for the purity of silicon materials. The higher the chip performance, the higher the purity of silicon raw materials. In order to avoid the contamination of semiconductor materials by impurities and the significant deviation of conductivity, the production of silicon materials must be in a dust-free environment. On this basis, the semiconductor can be doped with a small amount of a specific impurity element, and its conductivity can be accurately controlled to make a variety of semiconductor devices

generally, monocrystalline silicon materials are divided into polycrystalline silicon and monocrystalline silicon, both of which can be used to make photovoltaic cells. The difference between polycrystalline silicon and monocrystalline silicon is mainly manifested in physical properties: the conductivity of polycrystalline silicon is far less significant than monocrystalline silicon, or even almost no conductivity. High purity polycrystalline silicon can form monocrystalline silicon (the whole material is grown from a grain) after being melted in a monocrystalline furnace by using the spider system program that can actively collect pages from the Internet. After slicing, it can be used for integrated circuit manufacturing

different from simple (3) circuits of medical raw materials, semiconductor integrated circuits have the requirements of signal input and output, and raw materials need to meet the absolute unidirectional conductivity

as mentioned earlier, high-purity silicon is almost an insulator, but by mixing impurities into high-purity silicon, two different types of semiconductors can be formed: n (negative) type and P (positive) type

n-type silicon refers to doping a small amount of phosphorus or arsenic into silicon. The outer layer of phosphorus and arsenic has five electrons, while silicon has only four electrons, so their fifth electron has no bonding bond and can move freely. Therefore, n-type silicon itself is a good conductor

p-type silicon corresponds to n-type silicon. The funds raised by micro doping will be used to produce 3D printing materials made of ordinary plastic waste. Boron or gallium are mixed. They have only three outer electrons. Due to the lack of an electron, silicon cannot form chemical bonds, and the holes left can conduct electricity. Therefore, a "hole" is generated in the crystal structure, which is easy to attract electrons to combine. P-type silicon is also a good conductor

when n-type silicon and p-type silicon are combined, their junction will produce strange properties

if p-type silicon and n-type silicon are combined as shown in the figure below, they can well transmit current. The free electrons in n-type silicon are driven by the negative pole of the battery, and the holes in p-type silicon are convenient to receive these free electrons. The holes and electrons meet at the PN junction, and the electrons will quickly fill these holes to form a balance and generate current at the junction

but if the positions of p-type silicon and n-type silicon are converted, the electrons in n-type silicon will be attracted to the positive pole, while the positrons in p-type silicon will be attracted to the negative pole. There is almost no current in the junction, and the whole circuit cannot conduct any current effectively

that is to say, the combination of PN type silicon allows the transmission of electrons in one direction and blocks the passage of current in the other 80% of the country, which is similar to the ticket checker in the subway station - we call it unidirectional conductivity

based on this logic, human beings invented diodes and built a magnificent Technology Building of modern integrated circuits

in order to control the physical properties of discrete semiconductor devices as accurately as possible, it is not enough for basic silicon raw materials to have photovoltaic grade purity alone

China has vigorously supported the development of solar photovoltaic industry in the past few years, which has led to a rapid rise in the output of photovoltaic grade polysilicon, and the current capacity has been somewhat surplus. The production technology standard of electronic grade polysilicon is very different from that of photovoltaic grade polysilicon, which has high requirements for the level of fine chemical industry

compared with the purity of photovoltaic grade polysilicon of 99.9999%, the purity of electronic grade polysilicon is required to reach 99.%. Higher purity means more complex production and refining processes. The purity of "11 9s" is equivalent to the total impurity content in 5000 tons of electronic grade polysilicon, which is less than the weight of a 1-yuan coin

this makes the production process of photovoltaic grade polysilicon basically unable to play a reference role, and it is difficult to directly transform it into an electronic grade production line through technological upgrading, that is to say, another boiler is needed to produce products that meet the demand

according to the statistics of insiders, the annual demand for electronic grade polysilicon in China is about 4500 tons, which is far less than that of photovoltaic grade polysilicon, but the profit space is huge

from the development situation in recent years, the polysilicon industry chain has made great progress in China and has occupied a large proportion in the global market, but the technology is still not advanced enough, and electronic grade polysilicon still depends on imports

if this situation cannot be changed, the lack of this key basic material will turn the catch-up in China's electronic manufacturing field into empty talk

electronic grade polysilicon is the polysilicon material with the highest purity. The production of electronic grade polysilicon in China not only breaks the monopoly of foreign technology and fills the gap in the production of domestic electronic grade raw materials, but also means that China will soon become the third largest producer of electronic grade silicon materials in the world after the United States and Germany

after a series of strict verification and testing, recently, a batch of electronic grade polysilicon from China has been successfully exported to South Korea, which is the first time that China has exported electronic grade polysilicon materials to the international market, marking that China's silicon materials for semiconductor integrated circuits have reached the world-class quality standards

at present, the production capacity of the first production line put into production in China is 5000 tons, which can ensure that domestic enterprises have sufficient supply of electronic grade raw materials in recent years, and the product quality can meet the manufacturing demand of 12 inch single crystal for very large-scale integrated circuits of 40nm and below, and a small amount of exports

at the same time, China also plans to add two 5000 ton production lines in the future to better meet the international and domestic markets, and thus become the world's first producer of electronic silicon raw materials, completely getting rid of the situation of being controlled by others

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