First, polysilicon is a form of elemental silicon. There is no particularly obvious essential difference between the two, except that the crystal form of the chemical substance structure is different.

When molten elemental silicon solidifies under supercooling conditions, silicon atoms are arranged in the form of a diamond lattice into many crystal nuclei. If these crystal nuclei grow into crystal grains with different crystal plane orientations, these crystal grains combine to crystallize into polysilicon .

Polycrystalline silicon can be used as a raw material for pulling monocrystalline silicon. The difference between polycrystalline silicon and monocrystalline silicon is mainly manifested in physical properties. For example, in terms of mechanical properties, optical properties, and thermal properties, the anisotropy is far less obvious than that of single crystal silicon; in terms of electrical properties, the conductivity of polycrystalline silicon crystals is far less significant than that of single crystal silicon, or even almost no conductivity.

Polycrystalline silicon is a direct material for the production of elemental silicon. It is a silver-gray crystal with a metallic color. It is a non-metallic material that is purified by a series of physical and chemical reactions with industrial silicon as a raw material.

Polysilicon has the properties of semiconductors and is the basic material of semiconductor products widely used in contemporary artificial intelligence, automatic control, information processing, and photoelectric conversion.