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Introduction to the principle of silicon crystal growth furnace
- Mar 12, 2018 -

Firstly, the high purity polysilicon raw material is put into the high purity quartz crucible, which is melted by the high temperature produced by the graphite heater. Then, the molten silicon liquid slightly to cool down, so that it produces a certain degree of supercooled, and then a fixed on the seed crystal axis of the silicon crystal (called Seed crystal) into the melt surface, to the seed crystal and melt melt, slowly upwards pull the seed crystal , the crystals will grow at the bottom of the seed crystal; the control seed crystal grows a length to be about 100mm, the diameter is 3~5mm the fine neck, uses in eliminates the high temperature solution to the seed crystal intense thermal shock to produce the atomic permutation dislocation, this process is the crystallization; Subsequently, enlarges the crystal diameter to the craft request the size, generally is 75~ 300mm, this process is called the shoulder; then, a sudden increase in the speed of the shoulder operation, so that the shoulder approximate right angle; Then, into the equal-diameter process, by controlling the temperature of the thermal field and crystal lifting speed, the growth of a certain diameter of the size of a single crystal column; Finally, when most of the silicon solution is finished, The crystal is gradually reduced to form a tail-shaped cone, called the finishing process. Such a single crystal pull process is basically completed, after a certain heat preservation cooling can be removed.

The direct pull method, also called Chekrauski (J.czochralski) method. This method was established in 1917 by the Chekrauski of a crystal growth method, using direct-pulling growth of single crystal equipment and technology is relatively simple, easy to achieve automatic control, high production efficiency, easy to prepare large diameter single crystals, easy to control the concentration of impurities in single crystals, can be prepared with low resistivity single crystal. According to statistics, the world's production of Silicon Monocrystalline 70%~80% is produced by direct-pull method.