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Method for fabricating N-type solar cell

A technology of solar cells and fabrication methods, which are applied to circuits, photovoltaic power generation, electrical components, etc., can solve the problems of destroying the passivation effect of the TOPCon structure, reducing the open-circuit voltage and conversion efficiency of solar cells, etc. Voltage and conversion efficiency improvement, effect of improving open circuit voltage and conversion efficiency

Inactive Publication Date: 2019-08-06
KINGSTONE SEMICONDUCTOR LIMITED COMPANY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved in the present invention is to overcome the process of screen printing conductive paste and then high-temperature sintering to make metal electrodes in the prior art, which will cause silver paste to burn through polysilicon and tunnel oxide layer to directly contact with silicon substrate, destroying the TOPCon structure The passivation effect, the direct contact between metal and silicon will bring serious minority carrier recombination, which will reduce the open circuit voltage and conversion efficiency of solar cells, and provide an N-type solar cell that can effectively reduce the negative impact of minority carrier recombination on solar cells. Production Method

Method used

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  • Method for fabricating N-type solar cell

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Embodiment 1

[0046] refer to Figure 1-Figure 6 , to introduce the fabrication method of the N-type solar cell of this embodiment. First, the N-type silicon substrate 1 is textured on both sides, and then the N-type silicon substrate 1 is diffused with boron to form a P-type doped layer 2 on the front surface of the N-type silicon substrate 1 as a front emitter. During the boron diffusion process, the back edge of the N-type silicon substrate is also affected by the boron diffusion, forming a P-type doped region (not shown in the figure). Therefore, after boron diffusion, the N-type silicon substrate is etched backside to remove the P-type doped regions at these edges, resulting in the following image 3 structure shown.

[0047] Then refer to Figure 4 Phosphorus ion implantation is performed on the entire back surface of the N-type silicon substrate to form an N-type doped layer 3 as a phosphorus back field, wherein the implantation energy of phosphorus ions is 10keV, and the dose is ...

Embodiment 2

[0052] First according to the front process described in embodiment 1 to obtain such as image 3 The structure shown, next, differs from Example 1 in that:

[0053] refer to Figure 7 , in the back field process, local phosphorus implantation is used to form an N-type doped region 31 only in a local region of the N-type silicon substrate 1, and the width of the N-type doped region 31 is 200um. Phosphorus ion implantation energy is 10keV, dose is 2e15 / cm 2 .

[0054] Then refer to Figure 8 , using a thermal oxidation process to form silicon oxide 4 with a thickness of 2nm. Subsequently, N-type polysilicon is formed on silicon oxide 4 , specifically, phosphorous-doped polysilicon with a thickness of 300 nm is formed by PECVD, followed by annealing at 850° C. for 30 minutes to form N-type polysilicon 5 . Then screen print the back electrode 6 on the N-type polysilicon 5 at the position corresponding to the N-type doped region 31, and then sinter to obtain Figure 9 structu...

Embodiment 3

[0057] The basic principle of embodiment 3 is the same as that of embodiment 1, and between step S6 and step S7 also includes forming a passivation layer on the front surface of the N-type silicon substrate. In this embodiment, Al with a thickness of 5nm 2 o 3 as a passivation layer.

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Abstract

The invention discloses a method for fabricating an N-type solar cell, comprising steps of texturing the double sides of an N-type silicon substrate; performing boron diffusion on the N-type silicon substrate to form a P-type doped layer as a front emitter in the front surface of the N-type silicon substrate; etching the back side of the N-type silicon substrate to remove a P-type doped region formed in the back surface of the N-type silicon substrate during diffusion; performing N-type doped element ion implantation on the back side of the N-type silicon substrate to form an N-type doped backfield; forming an oxide layer on the back side of the N-type silicon substrate; and forming an N-type polycrystalline silicon layer on the oxide layer. Because of the presence of the heavily doped back field, low recombination is formed at the joint of metal and silicon, and the open-circuit voltage and the conversion efficiency of the solar cell are improved.

Description

technical field [0001] The invention relates to a method for manufacturing a solar cell, in particular to a method for manufacturing an N-type solar cell. Background technique [0002] N-type solar cells have attracted more and more attention because of their high conversion efficiency, ultra-low light-induced attenuation, and double-sided power generation characteristics. At present, N-type double-sided cells have achieved large-scale mass production. However, limited by the passivation of the back side and the minority carrier recombination at the metal-semiconductor contact, the conversion efficiency of N-type bifacial cells will reach a bottleneck at 22%. The development of TOPCon (Tunneling Oxide Polysilicon Passivation Contact) technology provides space for further improving efficiency of N-type solar cells. The back of the N-type solar cell adopts TOPCon technology, and uses the N-type polysilicon on the back to form the carrier selective electrode on the back, whic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L31/18
CPCH01L31/18H01L31/1864H01L31/1868Y02E10/50Y02P70/50
Inventor 何川
Owner KINGSTONE SEMICONDUCTOR LIMITED COMPANY