The main functions of silicon carbide boat support and quartz boat support are the same. Silicon carbide boat support has excellent performance but high price. It constitutes an alternative relationship with quartz boat support in battery processing equipment with harsh working conditions (such as LPCVD equipment and boron diffusion equipment). In battery processing equipment with ordinary working conditions, due to price relations, silicon carbide and quartz boat support become coexisting and competing categories.
① Substitution relationship in LPCVD and boron diffusion equipment
LPCVD equipment is used for battery cell tunneling oxidation and doped polysilicon layer preparation process. Working principle:
Under low-pressure atmosphere, combined with appropriate temperature, chemical reaction and deposition film formation are achieved to prepare ultra-thin tunneling oxide layer and polysilicon film. In the tunneling oxidation and doped polysilicon layer preparation process, the boat support has a high working temperature and a silicon film will be deposited on the surface. The thermal expansion coefficient of quartz is quite different from that of silicon. When used in the above process, it is necessary to regularly pickle and remove the silicon deposited on the surface to prevent the quartz boat support from breaking due to thermal expansion and contraction due to the different thermal expansion coefficient from silicon. Due to frequent pickling and low high-temperature strength, the quartz boat holder has a short life and is frequently replaced in the tunnel oxidation and doped polysilicon layer preparation process, which significantly increases the production cost of the battery cell. The expansion coefficient of silicon carbide is close to that of silicon. The integrated silicon carbide boat holder does not require pickling in the tunnel oxidation and doped polysilicon layer preparation process. It has high high-temperature strength and long service life. It is a good alternative to the quartz boat holder.
Boron expansion equipment is mainly used for the process of doping boron elements on the N-type silicon wafer substrate of the battery cell to prepare the P-type emitter to form a PN junction. The working principle is to realize chemical reaction and molecular deposition film formation in a high-temperature atmosphere. After the film is formed, it can be diffused by high-temperature heating to realize the doping function of the silicon wafer surface. Due to the high working temperature of the boron expansion equipment, the quartz boat holder has low high-temperature strength and a short service life in the boron expansion equipment. The integrated silicon carbide boat holder has high high-temperature strength and is a good alternative to the quartz boat holder in the boron expansion process.
② Substitution relationship in other process equipment
SiC boat supports have tight production capacity and excellent performance. Their pricing is generally higher than that of quartz boat supports. In general working conditions of cell processing equipment, the difference in service life between SiC boat supports and quartz boat supports is small. Downstream customers mainly compare and choose between price and performance based on their own processes and needs. SiC boat supports and quartz boat supports have become coexistent and competitive. However, the gross profit margin of SiC boat supports is relatively high at present. With the decline in the production cost of SiC boat supports, if the selling price of SiC boat supports actively declines, it will also pose a greater competitiveness to quartz boat supports.
Usage ratio
The cell technology route is mainly PERC technology and TOPCon technology. The market share of PERC technology is 88%, and the market share of TOPCon technology is 8.3%. The combined market share of the two is 96.30%.
As shown in the figure below:
In PERC technology, boat supports are required for the front phosphorus diffusion and annealing processes. In TOPCon technology, boat supports are required for the front boron diffusion, LPCVD, back phosphorus diffusion and annealing processes. At present, silicon carbide boat supports are mainly used in the LPCVD process of TOPCon technology, and their application in the boron diffusion process has been mainly verified.
Figure Application of boat supports in the cell processing process
Note: After the front and back coating of PERC and TOPCon technologies, there are still links such as screen printing, sintering and testing and sorting, which do not involve the use of boat supports and are not listed in the above figure.
Post time: Oct-15-2024