Everyone knows that quartz crucibles have many advantages, but if we don't pay attention to their production, manufacturing, and use, it can cause deformation. So, what are the reasons for the deformation of such crucibles? This article has explained the specific content to everyone.
1、 Improper loading method
1. The contact between the material on the liquid level line and the quartz crucible is in a surface contact state, which can easily cause edge hanging and crucible deformation during the melting process.
2. The upper part is filled with small and fine particles, which can easily cause deformation when the lower part has already dissolved and the upper part is in a crystalline state during melting.
2、 Improper melting method
At present, hot screen technology is commonly used in the production of solar single crystals, and the use of hot screens is generally divided into two types: top mounted and bottom mounted. There are two reasons for deformation caused by improper melting methods:
1. If the upper part is melted first in the hanging type heat screen, that is, the crucible position is lowered to a lower position first, allowing the upper material to melt first, this method is prone to deformation during the melting process.
2. In a bottom mounted thermal screen, the upper part is generally not easily deformed, but if the upper silicon material melts and sinks, and the crucible position is not raised in time, it will cause bulging deformation at the bottom.
3、 Improper melt power
1. The temperature is too high
Due to the melting point of silicon being 1420 ℃, the typical melt temperature is around 1550-1600 ℃. If the melt temperature is too high, deformation is prone to occur during the melt process.
2. Low temperature
When the temperature of the molten material in a quartz crucible is low, the upper part of the crucible is prone to a state of melting but not melting at the contact point with the crucible wall. When the lower part of the material has melted and the block material with hanging edges on the upper part is pulled down, deformation occurs.
4、 Raw material issues
The quality of raw materials varies greatly, with impurities much higher than the original polycrystalline material. The acid washing process is not perfect, which has a significant impact on the normal use of crucibles, mainly manifested in the easy occurrence of severe crystallization.
5、 Improper operation
During production cleaning and packaging, if contaminated, crystallization may occur, causing the original thickness to thin and the strength to decrease, resulting in deformation. And during the process of placing products and filling silicon materials, improper operation can cause contamination and deformation.
We have learned that there are many reasons for the deformation of quartz crucibles, so in the future use process, we should pay attention to analyzing the reasons and make corresponding solutions.