Crystal Growth

 

Atoms of highly pure molten silicon are attached to a small seed crystal. This silicon mixture consists of many electrically active elements that change its electrical properties. The process is executed under temperature at 2700F or 1482C. By accurately controlling the temperature gradients, rate of pulling and speed of rotation, it is possible to extract a large, single-crystal, cylindrical ingot from the melt.

 

This is normally performed in an inert atmosphere, such as argon, and in an inert chamber, such as quartz. The seed crystal is lowered into the molten polysilicon at the rapid rise of heat in the furnace. Cooling follows thereafter, and crystal growth occurs around the seed.