Method for improving passivation performance of tunneling oxygen/polycrystalline silicon passivation contact structure

Abstract

The invention discloses a method for improving the passivation performance of a tunneling oxygen/polycrystalline silicon passivation contact structure. The method comprises the steps of: directly carrying out medium and low temperature heat treatment on the tunneling oxygen/polycrystalline silicon passivation contact structure, or firstly depositing an oxide film on the surface of the doped silicon thin layer of the tunneling oxygen/polycrystalline silicon passivation contact structure, and then carrying out medium and low temperature heat treatment. According to the method, the passivation contact structure can achieve a good passivation effect, and the passivation performance of the tunneling oxygen/polycrystalline silicon passivation contact structure with different passivation levels can be improved; treatment methods are diversified; repeatability is high; required equipment is simple; and the process of the method is completely suitable for the back passivation of TOPCon cells.

Description

Technical field [0001] The invention relates to the technical field of solar cells, in particular to a method for improving the passivation performance of a tunneling oxygen / polysilicon passivation contact structure. Background technique [0002] The tunneling oxygen / polysilicon passivated contact (TOPCon or POLO or polysilicon passivated contact) solar cell is a new type of silicon solar cell proposed by the Fraunhofer Institute in Germany in 2013. The battery adopts an n-type silicon wafer. The back of the silicon wafer is covered with an ultra-thin silicon oxide layer with a thickness of less than 2nm, and then covered with a thin layer of doped silicon. The thin doped silicon layer is doped polysilicon or non-doped silicon. Crystalline silicon layer. The basic battery structure and passivation structure are as follows figure 1 Shown. At present, the back passivation structure of the battery adopts ultra-thin silicon oxide + phosphorus-doped polysilicon passivation structure...

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Problems solved by technology

[0005] 1. The FGA treatment method is relatively simple, has low equipment requirements, and is easy to apply industrially. However, the disadvantage is that the improvement effect on passivation is limited (usually <5mV), and the effect is not stable.

[0006] 2. The RPHP method and the silicon nitride method can significantly improve the passivation, usually (10-15mV), but the disadvantages are that these two methods require custom-made special plasma generation equipment, which is expensive, and the process requires the use of vacuum conditions and high yield. Low cost, cumbersome operation, difficult to achieve mass production of the production line

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