The polycrystalline graphite bottom plate is located under the crucible in the thermal field structure of the polycrystalline furnace, and is close to the graphite side plate on all sides. There is a directional solidification block under the graphite bottom plate.

The reasonable use of the graphite bottom plate can achieve a reasonable effect of the solid-liquid interface distribution of polycrystalline silicon in the growth process, which is conducive to impurity impurity during the growth process and can greatly improve the overall quality of the crystal.

In the polycrystalline thermal field, there are four graphite side plates. Each of the two graphite side plates in the four graphite side plates is connected to each other to form a square tube shape. 

The graphite electrode holder is used in the graphite crystal thermal field of the single crystal furnace to stabilize the graphite electrode in the thermal field and play a stable supporting role.