Silicon crystal technology at semi conductor industry is advanced the development considering it as a purpose to make “what is the most suitable crystal for a device” clear. A semiconductor device like ultra large scale integration and so on, has become the key to modern industry and its importance has been growing more and more. The mono-crystalline silicon has many advantageous characteristics for device technology, such as a thermal stability, a simple formation of oxide as an insulator, precise controllability of electrical type, and so on. The controls of oxygen concentration and distribution are the most important subjects in the Czochralski crystal. The oxygen concentration depends upon that in the melt in front of the crystal. Some of them have fatal effects on the devices even in the ultra trace, then the greatest care for contamination control must be taken in the crystal growth. The gettering is powerful technology for contamination control.