China PV 20 years: all rivers and lakes of wind and clouds record

To paraphrase the idiom of the annual industry review: "2020 will be an extraordinary year" for the polysilicon-photovoltaic industry.I have been writing about it for 10 years. From a full-time photovoltaic journalist to a staff member of an engineering company investing in polysilicon and photovoltaic industry, the polysilicon and photovoltaic industry has always been affecting my thoughts in the past 10 years.This "extraordinary" is not simply a writing habit or a simple copy. Instead, from the beginning of this century to the present, China's polysilicon and photovoltaic industry has experienced great changes and ups and downs in just 20 years, which has fully condensed the development track of other industries for decades or even hundreds of years.

"When all go forward, do not forget the road we have taken;No matter how far we go and how bright our future may be, we should never forget the past and why we set out."On the occasion of the critical juncture of the "13th Five-Year Plan" and the "14th Five-Year Plan", standing at the intersection of the "two centenary", looking back at the development of the industry, I hope that I can carry on the history with writing between the gains and losses, and accumulate the strength of steady progress for the next section of the road.

Think memorial, think wish.

Origin: the birth of photovoltaic

(19th century ~ 1960s)

China's silicon industry is in its infancy

Continuing to achieve major breakthroughs

But by then, germanium had been replaced in the United States with single silicon crystals, which dominated because of their more market-based properties and uses.In China's "12 years of science and technology development vision", the research and development of silicon single crystal was ranked in 1968, 10 years later, which means that China will lag behind foreign countries in this field for at least 10 years!

As mentioned above, silicon, an element abundant in the earth's crust, once successfully developed, purified and utilized, can be prepared into important semiconductor materials, which will have broad prospects in the preparation of transistors and integrated circuit chips.On this basis, in order to improve the life and motion speed of the electrons, researchers converted the polycrystalline structure of the material into a single crystal structure, this artificial culture of crystalline materials is called the single crystal growth technology.

In 1959, in order to catch up with the pace of foreign technology research and development, under the leadership of Lin Lanying et al., China started the production and research of silicon single crystal in advance of the planned time.

However, in the new China, argon, the most needed protective gas for making silicon single crystals, is extremely scarce.Argon is an important inert gas.In order to prevent oxides and other impurities from contamining the pulled single crystal during high temperature heating and thus affecting the quality of single crystal, argon is used as the protective gas in the furnace in the process of preparing single crystal of silicon.Argon was banned at the time and China could not produce it itself.Without argon, the development of silicon single crystal is almost impossible to succeed, which is the western consensus.

Against this background, Lin came up with the idea of "vacuuming", creatively using a mechanical pump and an oil diffusion pump to extract the vacuum, and using the seed protection cover she invented in the United States to make the process.After a period of scientific research, at the end of 1958, under her efforts, China's first silicon single crystal was born!The cylinder, 8 centimeters long and 5.08 centimeters in diameter, is like a small torch, igniting the hope of the development of China's semiconductor industry.China also became the third country in the world, after the United States and the Soviet Union, to produce single crystal silicon independently.

However, this single crystal is made by the furnace that produces single crystal of germanium. Due to the limitation of equipment conditions, the crystal integrity is poor and the dislocation density is large.The so-called "dislocation" is when the atoms are arranged in an irregular line, and the first one is lost, and the current passing through the line is confused.In order to produce disposition-free silicon single crystal, it is necessary to have a silicon single crystal furnace with reasonable design and high quality.For this reason, Lin Lanying also inspected the closed silicon single crystal furnace of the Soviet Union. After several months of tests, he found that the equipment of "Big Brother" also had defects that were difficult to make up for, so he decided to develop it separately.

In 1961, the first open-door silicon single crystal furnace was successfully manufactured in China, which solved the problem of "opening the door and maintaining high vacuum degree in the furnace".In 1962, the formal control work began, China's first dislocation - free silicon single crystal was successfully drawn, the quality of its products reached the world advanced level after testing.At the same time, this "meritorious furnace" also won the national new product award, and the next year in the Tokyo International Industry Fair on display, then mass production, exported to many countries.In 1962, Lin Lanying successfully prepared GaAs single crystal by horizontal Bridgman growth method. GaAs is the second generation semiconductor material, which is very important.During this period, Lin Lanying turned his attention to the development of silicon epitaxial materials.It is a material with two layers of silicon single crystal structure, which is of great strategic importance.On the basis of single crystal silicon, she succeeded again.Some new silicon devices made of this silicon epitaxial material make military radar, radio and remote sensing measuring instruments more accurate and reliable.It is worth mentioning that this material played a significant role in the construction of the first atomic bomb.Therefore, Lin Lanying became one of the scientists who made important contributions to the "two bombs and one satellite".

In the second year after Lin lanying successfully developed silicon single crystal, in September 1959, the silicon semiconductor workshop of 718 plant (North China radio equipment joint factory) also successfully pulled out the first silicon single crystal in China's semiconductor industry.In that year, Zhou Fengming, director of Beijing Electronic Tube Factory, accepted the task of developing silicon single crystal as required by Beijing, and made the furnace according to the drawing furnace blueprint he brought back, and began to develop silicon materials and silicon devices (he tried to produce silicon alloy triode).During this period, Beijing Electronic Tube Factory had 200 employees engaged in semiconductor production, with an annual output of nearly 1 million diodes and 30,000 triodes, and all germanium single crystals and components were produced by ourselves.