The role of molybdenum weight in single crystal furnace

The mainstream manufacturing method for single crystal is the Czochralski method. A very important component in the single crystal furnace of the Czochralski method is the weight. The weight is used to connect the seed crystal and the tungsten wire rope. The quality of the weight will directly affect the pulled single crystal.During the Czochralski method of growing single crystal silicon, a weight is connected to the seed crystal through a tungsten wire rope. The weight of the weight keeps the seed crystal in place and controls the growth rate of the crystal during the pulling process. The design and material selection of the weight need to consider its stability in a high temperature environment to ensure that the performance of the weight is not affected by temperature changes during the crystal growth process.The molybdenum content of the heavy hammer is not less than 99.95%, the physical density is above 9.9 g/cm3, and the high temperature resistance can reach above 1600°-1700°. The concentricity is the same as that of the molybdenum seed crystal chuck, the tolerance is within 0.02mm, the thread mouth is required to be smooth, without rotten teeth, and the product has a high finish.

Function of the weight：

1.Seed crystal connection: The weight is usually connected to the seed crystal (i.e. the initial part of the single crystal silicon). The weight of the weight is used to stabilize the position of the seed crystal, and the seed crystal is driven up by the pulling mechanism to achieve the pulling of the crystal, ensuring its verticality and stability during the growth process.

2.Rotation control: During the crystal growth process, the rotation speed of the crystal and the crucible needs to be controlled. The weight can drive the entire system to rotate through the connection with the seed crystal to control the rate and quality of crystal growth.

3.Weight balance: The weight of the weight needs to match the weight during the crystal growth process to maintain the balance of the system and prevent crystal growth defects caused by uneven weight.