Question about BCl3 boron pre-deposition

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Hello I'm a newbie process engineer in a semiconductor fab.
In our fab we have a process using BCl3 gas for boron pre-deposition, however it randomly generates defects on silicon wafers.
The defect is like triangular dislocation (since the silicon substrate is <111>)
Does anyone know the reason that generate this kind of defect and how to avoid or reduce the risk??

 

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The most likely cause of the triangular dislocation defects is due to an inadequate process temperature. BCl3 gas is highly reactive at elevated temperatures and can react with other elements in the chamber, forming a volatile boron-containing species that can deposit on the wafer surface. This deposition can form a stress gradient across the wafer surface, resulting in the formation of a dislocation. To reduce or avoid these types of defects, it is important to ensure that the process temperature is appropriate for the BCl3 gas being used. Additionally, the rate of gas flow should be monitored and controlled to prevent excessive deposition of boron-containing species on the wafer surface. Finally, proper maintenance of the process chamber is also essential to ensure a clean environment free from any contaminants that may lead to the formation of these types of defects.