2017年1月9日星期一

The two kinds of single crystal furnace control method

The two kinds of single crystal furnace control method
Do you know about single crystal furnace? Single crystal furnace in the process control method specific how should do?
The first: zone melting method
Zone melting method, the operation of the process is to avoid the pollution caused by chemical reaction between melt and crucible, and developed without crucible crystal growth process.
This method applies only to melt the surface tension coefficient of crystal growth. Vertical installed a polycrystal bar, use water cooled rf, melt heat should make one end of the stick. On the surface tension of the melt and levitation force produced by the electric field, make the melt and crystal rod sticking together. Put a treated with directional seed crystal end into the melt, using the relative motion of heater and crystal melt polycrystalline rods melt unceasingly, but on the other side gradually generated crystals. This method makes the growth of crystals will not polluted by the crucible.
The second: the czochralski method
Czochralski method is also called "klaas base method" (Czochralski method, hereinafter referred to as CZ method. Is the main method of single crystal silicon growth. The law is in czochralski method (CZ) single crystal furnace, the raw material (polysilicon) is placed in a crucible of the heated to a molten state, seed crystal, introduced into the molten silicon, seed crystal sandwiched between the lower end of the rod, appropriate control temperature. When the seed crystal and molten silicon to achieve balance, to support the surface tension of liquid and will be against the adsorption in the bottom of the seed crystal. The rotation while tyra seed crystal, the adsorption of melt movement will be as the seed crystal up. Upward movement in the process of the melt temperature to drop, will make the melt condensation into crystalline and grow into a single crystal rods as seed crystal direction.

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