The semiconductor material is refined through a process is known as zone refining. It is used for the production of high purity crystals; silicon for example has a melting temperature, so any impurity present in the crystal decreases the melting temperature. Thus zone refining process is based on the principal that the effect of impurities on the melting point of a material will control the impurity concentration of impurities material the molten and the just frozen. By maintaining the melt at specific temperature a single crystal of the material can be inserted into the molten mass on the end of the rod. After which it is possible to withdraw the single crystal having the molten material adhere to the crystal and solidify maintaining the same orientation. The phase diagram of silicon with impurity near the low-concentration region.