Chemistry What is amorphous silicon What is the role of amorphous silicon in semiconductor processes

Amorphous silicon (A-Si), also known as amorphous silicon, is an allotropic form of silicon.

Crystalline silicon is usually tetrahedral in shape.

arrangement, each silicon atom is located at the apex of the tetrahedron and covalently bonds with the other four silicon atoms.

Tightly bonded. This structure can be extended to a very large size, resulting in a stable lattice structure. However, amorphous silicon does not have such a ductive lattice structure, and the lattice network between atoms is disordered.

In other words, not all atoms are arranged in a tetrahedral strict alignment with other atoms. Due to this instability, some of the atoms in amorphous silicon contain dangling bonds. These dangling bonds have a significant negative impact on the properties of silicon as a conductor.

However, these dangling bonds can be filled with hydrogen, and upon hydrogenation, the density of the dangling bonds of amorphous silicon decreases significantly and is sufficient to reach semiconductor materials.

standards. However, the electrical conductivity of hydrogenated amorphous silicon will be significantly reduced under the irradiation of light, which is known as the WE effect (STAEBLER-WRONSKI effect).

Amorphous silicon (A-Si) has a variety of uses in semiconductor processes, including:

1.As the bottom layer of photoresist: amorphous silicon can form a flat film layer on the surface of the wafer, so that the photoresist can be evenly spread on the surface of the wafer, thereby improving the accuracy and stability of lithography.

2.As a diffusion inhibition layer: Amorphous silicon can form a thick film layer on the surface of the wafer, which can effectively inhibit the diffusion process, thereby controlling the size and performance of the macrocelery.

3.As the bottom layer of gate dust oxide: amorphous silicon can form a flat film on the surface of the wafer, so that the gate oxide can be evenly covered on the surface of the wafer, thus improving the performance of the transistor.

4.As a material for thin-film transistors (TFTs): Amorphous silicon can be used to fabricate the active layer of TFTs, enabling high-resolution liquid crystal displays and organic light-emitting dicast bipolar therapods (OLEDs).

In conclusion, amorphous silicon has a wide range of applications in semiconductor processes, which can improve the performance and stability of devices and promote the development of the semiconductor industry.

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To chemically extract amorphous silicon from polysilicon, a certain amount of polysilicon sample is obtained. Ensure that the sample is of high purity and free of impurities. The polysilicon sample is pretreated to remove oxides and organic impurities from the surface.

Common pretreatment methods include pickling, caustic washing, and hydrofluoric acid treatment. Dissolve the pretreated polysilicon sample in an appropriate solvent. Through appropriate chemical treatment, the amorphous silicon is separated from other impurities.

This can be achieved by adjusting solvent concentration, temperature, and pH parameters. After the amorphous silicon is separated, the amorphous silicon can be separated from the solution by precipitation filtration. The separated amorphous silicon is washed to remove residual solvents and impurities.

Appropriate solvents, alcohol water, and repeated washes can be used several times. Finally, the washed amorphous silicon is dried, and the oven vacuum drying method can be used.

How to chemically use amorphous silicon in polysilicon.

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To chemically extract amorphous silicon from polysilicon, a certain amount of polysilicon sample is obtained. Ensure that the sample is of high purity and free of impurities. The polysilica-like sail is pre-treated to remove oxides and organic impurities from the surface.

Common pretreatment methods include pickling, caustic washing, and hydrofluoric acid treatment. Dissolve the pretreated polysilicon sample in an appropriate solvent. Through appropriate chemical treatment, the amorphous silicon is separated from other impurities.

This can be achieved by adjusting solvent concentration, temperature, and pH parameters. After the amorphous silicon is separated, the amorphous silicon can be separated from the solution by precipitation filtration. The separated amorphous silicon is washed to remove residual solvents and impurities.

Appropriate solvents, alcohol water, and repeated washes can be used several times. Finally, the washed amorphous silicon is dried, and the oven vacuum drying method can be used.

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Extension: Amorphous silicon refers to an amorphous form of silicon. In general, crystal field bodies are composed of highly ordered arrangement of atoms and molecules, while amorphous substances lack this long-range ordered structure.

Due to the lack of lattice structure, the physical and chemical properties of amorphous old spine silicon are different from those of crystalline silicon.

Silica is used in the manufacture of flat glass, glass products, foundry sand, fiberglass, ceramic glaze, sandblasting for rust prevention, sand for filtration, fluxes, refractories, and in the manufacture of lightweight bubble concrete. Silica has a wide range of uses. Crystals, which are relatively rare in nature, can be used to make important components for the electronics industry, optical instruments and handicrafts.

Silica is an important raw material for the manufacture of optical fibers. Generally, the purer quartz can be used to make quartz glass. Quartz glass has a very small expansion coefficient, equivalent to 1 18 of ordinary glass, can withstand drastic changes in temperature, and has good acid resistance (except HF), therefore, quartz glass is often used to manufacture chemical instruments with high temperature resistance.

Quartz sand is often used as a raw material for glass and as a building material. Silica is used in the manufacture of glass, quartz glass, water glass, optical fibers, electronic industry....