Components

1. Furnace: It includes fused silicon crucible $(SiO_2)$, a graphite susceptor, a rotation mechanism (clockwise), heating element and power supply.
2. A crystal pulling mechanism: It includes a seed holder and a rotation mechanism counter clockwise.
3. Ambient control: It is very important in growth system. There must not be any oxygen inside the system. The graphite susceptor and graphite heater will react with oxygen to form $CO_2$. It should not react with Si. Therefore, oxygen should be removed from the chamber and fill it with Argon. It includes gas source, a flow control & an exhaust system.
4. Control system: A puller has microprocessor based control system to control the process parameters such as temperatures, crystal diameter, pull rate & rotation speed.

Working

1. Pieces of EGS (Electronic Grade Silicon) are placed in silicon $(SiO_2)$ crucible along with a small amount of doped silicon & melted. The melt temperature is stabilized at just above the silicon melting point $(1417^0 C)$
2. A small single crystal seed suitably oriented is suspended over the crucible in a chuck.
3. For growth the seed is lowered into the melt until its end is molten.
4. It is now slowly withdrawn resulting in a single crystal which grows by progressive fusing at the liquid – solid interface.
5. The crystal orientation of this seed will determine the orientation of the resulting pulled crystal and wafers. The amount of dopant placed in a crucible with silicon charge will determine the doping concentration in the resulting crystal.
6. The silicon atoms from the melt bond to the atoms in the seed, lattice plane by lattice plane forming a single crystal as the seed is pulled upwards.
7. The diameter is controlled by the pull rate. Fast pulling results in smaller diameter crystal.
8. The seed & crucible are rotated in opposite direction to promote more uniform growth.

Advantages

1. Capable of easily producing large diameter crystals from which large diameter wafers can be cut.
2. $O_2$ in interstitial sites improves yield strength up to $6.4 \times 10^{17} O_2$ concentrations, but if it is more then there is problem of $O_2$ precipitate. Precipitate attracts metallic impurities as well as it can act as a sink and they are called gettering centers. For power devices it reduces breakdown voltages.