The Czochralski Process and Silicon Wafers

Crystal silicon is a very essential part of the modern life. Most of the semiconductor devices are made up of mono-crystalline silicon. There are different methods used in growing crystals for silicon wafers. The Czochralski process is the most preferred method for high volume production of silicon single crystals.

History of Czochralski Method:

In 1916, a Polish metallurgist published a method for measuring maximum crystallization rates of metals. He was drawing metal wires from melts, eventually through these single crystalline wires growth occurs. He recognized that with this technique, a single crystal can be grown successfully if single crystal seed is used. The very first crystal grown by this technique is single geranium crystals in 1948. In 1949, it was recognized that silicon was a better semiconductor material. Crystals grown using this method are referred to as Cz-Si crystals or monocrystalline Czochralski silicon.

Overview of Czochralski Process:

The process begins by melting high purity silicon in a crucible. The Dopants are added into the melt at this point. The choice of the impurity depends upon the end result of the wafer. Boron or phosphorus is often added to alter the silicon into p-type or n-type Si wafer. The electrical properties of silicon also change with the addition of dopant. After this a rod mounted with seed crystal which is slowly pulled upwards, this rod has already been dipped into the molten silicon. There are several factors on which wafer size and diameter depends. The speed of rotation and pulling rate determines the production of a large, single crystal, cylindrical ingot. The diameter of the crystal is dependent on the pull velocity. Once the crystal is produced, they can be cut into thin slices and polished to be used as starting materials for chip production.

There are several processes in which crystalline materials are grown for the end use of the wafer. The one of the processes used by various silicon wafer supplier is known as the Czochralski Process. All most all electronic devices today are depended on the Czochralski Process for wafer development for the production of silicon wafers.

#siliconwafersupplier