Silicon electronic grade polycrystalline

Aside from experimental and developing processes, there are three competing commercial processes for further refining metallurgical silicon into semiconductor grade polycrystalline silicon (polysilicon) Siemens, Union Carbide Chemicals, and Ethyl Corporation methods. This industry exists primarily to support the electronics industry. 

Purified polycrystalline CVD silicon from this reaction is then melted and a single-crystal boule weighing as much or more than 50 kg, and having a diameter up to 20 cm, is pulled from the melt by Czochralski growth (8). Metallurgical-grade silicon is not sufficiendy pure for applications in electronics... 

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