Heterojunction Solar Cell Structure With TOPCON Back Contact
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Solution Overview
Problem
Heterojunction solar cell technology faces high equipment costs due to expensive plate-type plasma-enhanced chemical vapor deposition (PECVD) coating equipment, making it less competitive with PERC technology in terms of comprehensive equipment investment.
Innovation Solution
A manufacturing method for heterojunction solar cells using tunnel oxide passivated contact (TOPCON) technology with a tunnel oxide layer and N-type polysilicon layer on the back surface, combined with a P-type oxygen-doped microcrystalline silicon layer on the front surface, which enhances passivation, conductivity, and optical band gap, while omitting roll coating and silicon nitride protective layers to reduce equipment investment and production complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If plate-type PECVD coating equipment is used for amorphous silicon or microcrystalline silicon, then high conversion efficiency is achieved, but equipment cost increases significantly
Solution Approach 1:
The patent replaces expensive plate-type PECVD equipment with more affordable deposition equipment, accepting that the equipment itself is less sophisticated while maintaining film quality through optimized process parameters and material selection
Solution Approach 2:
The patent modifies deposition parameters including temperature, pressure, gas flow rates, and layer thickness to achieve high conversion efficiency using simpler, lower-cost equipment instead of relying on complex plate-type PECVD systems
2Reliability
If heterojunction technology is adopted, then high conversion efficiency and high stability are achieved, but comprehensive equipment investment increases
Solution Approach 1:
The patent divides the semiconductor substrate into distinct regions with different passivating contacts (n-type on one surface, p-type on the other), allowing each region to be optimized independently while using simpler, more cost-effective equipment for each layer deposition
Solution Approach 2:
The patent combines multiple material layers including silicon oxide, silicon nitride, amorphous silicon, and microcrystalline silicon in a composite structure that achieves high stability and conversion efficiency without requiring expensive single-step PECVD equipment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves good passivation and conductivity, improves open-circuit voltage and fill factor, and significantly lowers the total cost of heterojunction devices by reducing the need for expensive flat-plate PECVD equipment, while ensuring high efficiency and stability.
Implementation Method 1
forming a tunnel oxide layer on a surface of a semiconductor substrate
Implementation Method 2
forming, by plasma-enhanced CVD (PEVCD) or hot-wire CVD, the P-type oxygen-doped microcrystalline silicon layer laminated by at least one oxygen-containing microcrystalline layer and at least one oxygen-free microcrystalline layer
Data Source
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AI summary
The present disclosure belongs to the technical field of solar cells, and provides a heterojunction solar cell and a manufacturing method thereof. The manufacturing method includes the following steps: A: forming a tunnel oxide layer on a surface of a semiconductor substrate; B: forming an N-type polysilicon layer on the tunnel oxide layer; C: forming a mask layer on the N-type polysilicon layer of a first main surface of the semiconductor substrate; D: performing texturing and cleaning on a second main surface of the semiconductor substrate, and removing the mask layer; E: forming a second intrinsic amorphous silicon layer on the second main surface of the semiconductor substrate; and F: forming a P-type oxygen-doped microcrystalline silicon layer on the second intrinsic amorphous silicon layer. With a simple process, the manufacturing method of the heterojunction solar cell keeps not only the high conductivity and low equipment investment of the N-type polysilicon layer, but also the desirable passivation and high open-circuit voltage of a heterojunction technology.