Question

Method used for obtained highly pure silicon, used as a semiconductor material, is

• A. oxidation
• B. electrochemical
• C. crystallization
• D. zone refining

Answer 1

The correct option is D zone refining

High purity silicon is required for the semiconductor industry and the needed levels cannot be reached by chemical methods alone. So for this;
A standard technique for purifying semiconductors (zone refining process) is used. In this, a horizontal semi-cylinder of material is held in a boat made from an unreactive material such as quartz and a narrow molten zone is passed from one end to the other of the charge. At the end of the pass the heater is rapidly moved to the beginning of the charge and the process is repeated. Impurities are dissolved in the molten zone and preferentially segregated to the first to freeze or last to freeze ends of the charge.