Coating equipment and method for tube-type PERC solar cells

Abstract

The invention discloses coating equipment for tube-type PERC solar cells. The coating equipment comprises a wafer loading region, a furnace body, a gas cabinet, a vacuum system, a heating system, a control system and a graphite boat; the gas cabinet is provided with a first gas pipeline for introducing silane, a second gas pipeline for introducing ammonia, a third gas pipeline for introducing trimethylaluminum, a fourth gas pipeline for introducing laughing gas and a fifth gas pipeline for introducing methane; the graphite boat is used for loading or unloading a silicon wafer; before being used or after being coated many times, the graphite boat needs to be subjected to pretreatment comprising the steps: drying the graphite boat; and coating at least one layer of silicon carbide film on the surface of the dried graphite boat. Correspondingly, the invention further discloses a coating method for tube-type PERC solar cells. By using the coating equipment and method, the pretreatment step of the graphite boat is simplified, the consumption of the silicon wafer is reduced, the silicon wafer is prevented from being scratched, and the EL yield of the cells is increased.

Description

technical field [0001] The invention relates to the field of PERC solar cells, in particular to a coating device for a tubular PERC solar cell and a coating method for a tubular PERC solar cell. Background technique [0002] With the higher and higher requirements for the photoelectric conversion efficiency of crystalline silicon cells, people began to study the back passivation solar cell technology. The current mainstream method is to use plate PECVD to coat the back. Plate PECVD consists of different chambers. Each chamber is coated with a layer of film. Once the equipment is fixed, the number of layers of the composite film has been fixed. Therefore, the disadvantages of plate PECVD are: The combination of composite films cannot be flexibly adjusted, and the passivation effect of the back film cannot be better optimized, thereby limiting the photoelectric conversion efficiency of the battery. At the same time, plate PECVD uses an indirect plasma method, and the passivat...

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Problems solved by technology

[0007] However, using tubular PECVD to make the back film of the PERC battery, scratches seriously affect the qualified rate of the finished battery. The problem is that, during the process of inserting the wafer into the graphite boat, the front side of the silicon wafer will contact the graphite boat wall, and the PN junction on the front side will be damaged. Scratches, resulting in scratches in the EL test, affecting the electrical performance of the battery

[0010] However, the resistivity of silicon nitride is very high, which affects the uniformity of the aluminum oxide coating on the back. EL testing will produce black edges at the corners, black edges at stuck points, etc., which will affect the EL yield of the battery. It is also found in production that there are The battery conversion efficiency of EL black edge is obviously lower

Silicon nitride plating on inserts consumes a lot of silicon wafers, because it takes a long time for the inserts to be coated, and the silicon wafers will be greatly bent because the surface coating is too thick, resulting in the interruption of the coating process and the need for re-plating, which takes up production time

Use some unqualified chips, the degree of bending is greater, so the silicon wafers inserted into the boat should not be too bad, which will seriously consume the silicon wafers, and the cost is high

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