Back passivation contact structure, preparation method thereof and solar cell

Abstract

The invention discloses a back passivation contact structure, a preparation method thereof and a solar cell. The method comprises the following steps: depositing a tunneling oxide layer on the back surface of a silicon wafer; sequentially and alternately depositing intrinsic polycrystalline silicon layers and doped polycrystalline silicon layers on the surface of the tunneling oxide layer in a direction far away from the silicon wafer to form a laminated film layer, wherein the last layer of the laminated film layer is a doped polycrystalline silicon layer; and eactivating doped atoms in the doped polycrystalline silicon layer, and diffusing the doped atoms to the intrinsic polycrystalline silicon layer, so that the laminated film layer becomes a complete doped film layer, and the passivation contact structure is obtained. The intrinsic polycrystalline silicon layers and the doped polycrystalline silicon layers are alternately deposited to form the laminated film layer, the doped atoms in the doped polycrystalline silicon layers are activated, so that the doped atoms are diffused into the intrinsic polycrystalline silicon layers, and all parts of the laminated film layer are doped with the doped atoms. The intrinsic polycrystalline silicon layers are prepared in the laminated film layer, and the deposition speed of the intrinsic polycrystalline silicon layers is high, so that the preparation time is shortened under the condition that the thickness of the doped film layer is the same.

Description

technical field [0001] The present application relates to the field of photovoltaic technology, in particular to a back passivation contact structure, a preparation method thereof, and a solar cell. Background technique [0002] In solar cells, the TOPCon (Tunnel Oxide Passivated Contact) cell has a passivation contact structure formed by a tunnel oxide layer and a doped polysilicon film on the back, which can block the recombination of minority carriers and holes, and increase the open circuit voltage and short circuit current of the cell. At present, when preparing doped polysilicon thin films, one preparation method is to use LPCVD (Low Pressure Chemical Vapor Deposition, low pressure chemical vapor deposition) method to deposit in-situ doped polysilicon thin films, and perform heat treatment to activate dopant atoms, but the in-situ The deposition rate of doped polysilicon film is quite slow, which is less than half of the deposition rate of intrinsic polysilicon film, w...

AI Technical Summary

Problems solved by technology

At present, when preparing doped polysilicon thin films, one preparation method is to use LPCVD (Low Pressure Chemical Vapor Deposition, low pressure chemical vapor deposition) method to deposit in-situ doped polysilicon thin films, and perform heat treatment to activate dopant atoms, but the in-situ The deposition rate of doped polysilicon film is quite slow, which is less than half of the deposition rate of intrinsic polysilicon film, which seriously affects the production capacity of solar cells. Too slow deposition rate greatly limits the application of LPCVD method to deposit in-situ doped polysilicon film in the photovoltaic industry Applications

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