polycrystalline silicon properties

Polycrystalline silicon is a kind of new form. Molten elemental silicon in cold conditions, the silicon atom to clot grid work arranged in a form of diamond nucleation, such as these forms many grow the grain and different faces orientation is the grain together, into polycrystalline silicon crystals. Polycrystalline silicon can be control of raw materials, polycrystalline silicon and monocrystalline silicon difference is mainly manifested in the physical properties. For example, in the mechanical properties, optical properties and thermal properties of the anisotropic aspects, rather than monocrystalline silicon is obvious; In the electrical properties, polycrystalline silicon crystals in the conductivity of the much less significant, and even almost no single crystal silicon electrical conductivity. In the chemical activity, two tiny differences. Polycrystalline and monocrystalline silicon can be distinguished from the outside, but the real identify must through the analysis of protein crystal orb direction, conductive type and resistivity, etc.
Polycrystalline silicon properties: grey metallic luster. Density 2.32 ~ 2.34. Melting point 1410 ℃. Boiling point 2355 ℃. Soluble in hydrofluoric acid and nitric acid in the mix, insoluble in water, nitric acid and hydrochloric acid. Hardness between ge and quartz, room temperature between very brittle, cutting apart easily. Heated to 800 ℃ above 1300 ℃ is ductility, show obvious when deformation. Under normal temperature, high temperature not lively with oxygen, nitrogen, and sulfur and reaction. High temperature melting state, has large chemical lively and sex, can and almost any material role. Has the properties of semiconductor, is a very important excellent semiconductor materials, but trace impurities can greatly affect its electrical conductivity. Electronic industry are widely used in the manufacturing of transistor radio, tape recorder, refrigerators, TVS, VCRS, electronic computers and other base materials. Silicon powder and dry by dry gas hydrogen in certain conditions, then through condensation, chlorinated distillation, reduction.
more about:Use of polysilicon

Use of polysilicon

Polycrystalline silicon is a kind of new form. Molten elemental silicon in cold conditions, the silicon atom to clot grid work arranged in a form of diamond nucleation, such as these forms many grow the grain and different faces orientation is the grain together, into polycrystalline silicon crystals. Polycrystalline silicon can be control of raw materials, polycrystalline silicon and monocrystalline silicon difference is mainly manifested in the physical properties. For example, in the mechanical properties, optical properties and thermal properties of the anisotropic aspects, rather than monocrystalline silicon is obvious; In the electrical properties, polycrystalline silicon crystals in the conductivity of the much less significant, and even almost no single crystal silicon electrical conductivity. In the chemical activity, two tiny differences. Polycrystalline and monocrystalline silicon can be distinguished from the outside, but the real identify must through the analysis of protein crystal orb direction, conductive type and resistivity, etc.

At present, crystalline silicon materials (including polycrystalline and monocrystalline silicon) is the main photovoltaic material, its market share in 90% above, and in the next a long time also is still the mainstream of solar cells material. Polycrystalline silicon production technology for a long time is in the U.S., Japan, Germany, etc. Of the three countries seven company 10 factories, forming technology blockade, hand the condition of the market monopoly.
The demand of polysilicon mainly comes from the semiconductor and solar cells. According to the different requirements for purity, divided into electronic level and the sun energy level. Among them, used in electronic level of about 55%, the sun polysilicon polysilicon accounted for 45%, with energy photovoltaic industry in the rapid development of polycrystalline silicon solar cells, and the speed of growth in the demand for higher than the development of semiconductor polysilicon, predicts 2008 solar polycrystalline silicon the demand for more than electronic level polycrystalline silicon.

more about:Polysilicon
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