Effect of reduction furnace operating pressure on silicon deposition
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Let’s discuss the effect of the reduction furnace pressure on the silicon deposition rate.
Experiments have shown that it is beneficial for silicon deposition.
There is no definite mathematical relationship; generally speaking, an increase in pressure facilitates deposition. However, process conditions such as material ratio, reduction furnace structure, and air supply volume must be fully considered.
Sir, how is the operating pressure of 0.5 MPA calculated, and what should be the spray velocity?
Regarding this issue, from the perspective of molecular dynamics and thermodynamics of chlorosilanes, a higher pressure results in a higher deposition rate; high pressure is mainly due to smaller intermolecular distances, leading to a higher gas density per unit volume.
Increasing the operating pressure of the reduction furnace can boost the silicon deposition rate, but excessive pressure can disrupt the flow field of the reaction gases, resulting in a low primary conversion rate; therefore, it is necessary to find the optimal balance between the two.
It is recommended that you check the design values for various aspects such as the gas flow pattern, temperature, and pressure in your reduction furnace. The equipment manufacturers or design firms will establish corresponding parameters for you in advance; by controlling these parameters properly, you can achieve the optimal silicon deposition rate!
The typical range for this parameter is quite large; the optimal value still needs to be adjusted manually.
This is why skilled workers are necessary for restoration production. Everyone understands the principle behind it, but actual debugging requires practical experience!
Yes, at this time, the advantage of work experience becomes evident.
Reply to 5# luoye888: Agree. Research shows that high stress definitely increases the deposition rate (as described in polysilicon processing literature), and the principle behind this should be explained through kinetics.