Solar Cell Edge Region Structure for LPCVD Etching Control

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Solution Overview

Problem

The current process of forming semiconductor layers in solar cells using LPCVD leads to issues such as incomplete removal and over-etching of the doped silicon glass layer, resulting in surface defects and reduced photoelectric conversion efficiency.

Innovation Solution

The substrate is divided into an edge region and a center region, with different film layer designs for each, and a passivation layer covers the edge region to prevent over-etching, reducing surface defects and improving electrical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LPCVD is used to prepare the polycrystalline silicon layer, then the conductivity of majority carriers is improved, but incomplete removal and over-etching of the silicon glass layer occurs, causing surface defects

Engineering Contradiction:

Improveconductivity of majority carriersVSAvoidsurface quality of silicon glass layer

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the substrate into a center region and an edge region, applying different film layer designs to each. The center region receives the full stack including the polycrystalline silicon layer for high conductivity, while the edge region uses a simplified structure without this layer, preventing etching defects at the edges while maintaining optimal performance in the center.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the edge region substantially flush with or closer to the second surface than the center region, and selectively forming the polycrystalline silicon layer only in the center region. This local differentiation ensures that the edge region does not suffer from over-etching while the center region benefits from high carrier conductivity.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the edge region is made flush with or closer to the second surface than the center region, then over-etching is prevented, but additional processing steps are required

Engineering Contradiction:

Improveedge region flatnessVSAvoidsubstrate structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-forming the edge region to be substantially flush with or closer to the second surface than the center region before depositing the film layers. This preliminary structural preparation prevents over-etching issues during subsequent processing steps while maintaining a relatively simple overall device structure.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a passivation layer is formed over the edge region, then electrical recombination and leakage are reduced, but the device structure becomes more complex

Engineering Contradiction:

Improveelectrical performance at edgeVSAvoidfilm layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The passivation layer is applied selectively only to the edge region and not to the center region, where it is not needed. This localized application reduces electrical recombination and leakage at the edge while minimizing the overall structural complexity and material usage compared to a full-surface passivation layer.

Inventive Principle:

Principle #3Local quality

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

This approach enhances the photoelectric conversion efficiency by reducing electrical recombination and leakage at the cell edge, improving open circuit voltage and short circuit current.

Implementation Method 1

The solar cell generates carriers by using the photovoltaic effect principle and introduces the carriers out by using an electrode

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

Chemical passivation of the tunneling oxide layer and field passivation of the polycrystalline silicon layer can significantly reduce a recombination rate of minority carriers on the silicon surface

Methodology Applied

Scientific EffectChemical passivation:

Implementation Method 3

Chemical passivation of the tunneling oxide layer and field passivation of the polycrystalline silicon layer can significantly reduce a recombination rate of minority carriers on the silicon surface

Methodology Applied

Scientific EffectField passivation:

Implementation Method 4

Low pressure chemical vapor deposition (LPCVD) is a main technology to prepare the tunneling oxide layer and the polycrystalline silicon layer

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS20250221089A1Solar cell, method for preparing the same, and photovoltaic module

Publication Date: 2025.07.03 ZHEJIANG JINKO SOLAR CO LTD

AI summary

Provided are a solar cell, a method for preparing a solar cell, and a photovoltaic module, relating to the field of photovoltaics. The solar cell includes a substrate, a dielectric layer and a doped semiconductor layer which are stacked, a passivation layer, and electrodes. The substrate has a first surface. The first surface includes an edge region and a center region. The edge region surrounds the center region. The edge region is substantially flush with or closer to the second surface than the center region. The dielectric layer is formed over the center region. The passivation layer covers the edge region and a surface of the doped semiconductor layer facing away the dielectric layer. The electrodes are located in the center region, and penetrate the passivation layer in a thickness direction to be in electrical contact with the doped semiconductor layer.