Solar Cell Passivation Layer for Thin Wafer Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solar cells face inefficiencies due to high silicon wafer thickness requirements and manufacturing costs, as well as issues with light absorption and recombination velocities, especially when using thin silicon wafers without effective passivation layers.
Innovation Solution
A solar cell design incorporating a passivation layer with a three-layer structure of silicon oxide, silicon nitride, and silicon oxynitride, positioned between the semiconductor unit and the back surface electrode, which reduces back surface recombination velocity and increases light absorption efficiency, allowing for thinner silicon wafers and lower manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a thin silicon wafer is used, then manufacturing cost is reduced, but photoelectric transformation efficiency deteriorates due to insufficient light absorption
Solution Approach 1:
The passivation layer is divided into three distinct sub-layers (first passivation sub-layer, second passivation sub-layer, third passivation sub-layer) with different materials and functions. This segmentation allows each layer to address specific issues: the first layer provides basic passivation, the second layer enhances reflectance, and the third layer prevents material penetration, collectively solving the light absorption problem in thin wafers while maintaining efficiency
Solution Approach 2:
The patent employs a composite passivation layer structure combining silicon oxide, silicon nitride, and silicon oxynitride in specific sequences. This composite structure leverages the complementary properties of each material to achieve both high reflectance for light absorption and effective barrier properties, enabling thin wafer usage without sacrificing photoelectric efficiency
2Productivity
If a passivation layer is added to reduce recombination velocity, then photoelectric transformation efficiency is improved, but device complexity increases
Solution Approach 1:
The passivation layer is segmented into three functional sub-layers, each with specific thickness ranges and material compositions. This segmentation allows the complex passivation function to be distributed across multiple specialized layers, achieving high photoelectric efficiency through coordinated action of each layer while maintaining manufacturing feasibility
Solution Approach 2:
The patent optimizes specific parameters including the thickness of each passivation sub-layer (first: 50-200nm, second: 100-300nm, third: 50-200nm), material composition ratios, and deposition conditions. By precisely controlling these parameters, the complex three-layer structure achieves optimal performance with manageable manufacturing complexity
3Ease of manufacture
If high-temperature firing process is used to form back surface electrode, then electrode formation is improved, but passivation layer integrity deteriorates due to material penetration
Solution Approach 1:
The third passivation sub-layer is strategically positioned at the interface between the passivation layer and back surface electrode, specifically designed with materials having high thermal stability and low permeability. This localized quality enhancement at the critical interface region prevents material penetration during high-temperature firing while maintaining overall passivation layer integrity
Solution Approach 2:
The patent uses composite material composition in the passivation layer, particularly the third sub-layer containing silicon oxynitride or silicon oxide, which provides excellent thermal barrier properties. This composite structure allows the passivation layer to withstand high-temperature firing processes (above 700°C) used for electrode formation without degradation
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 passivation layer enhances photoelectric transformation efficiency by increasing back surface reflectance and reducing recombination velocities, enabling stable efficiency even with thinner silicon wafers and reducing manufacturing costs while preventing material penetration during high-temperature firing processes.
Implementation Method 1
the passivation layer 130 increases a back surface reflectance (BSR)
Implementation Method 2
the passivation layer 130 reduces a back surface recombination velocity (BSRV)
Implementation Method 3
The anti-reflective layer 110 may be positioned on the semiconductor unit 100 to suppress a reflection of light incident on the semiconductor unit 100
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A solar cell and a method of manufacturing the same are provided. The solar cell includes a semiconductor unit, an electrode, and a passivation layer between the semiconductor unit and the electrode. The passivation layer includes a first layer containing silicon oxide (SiOx), a second layer containing silicon nitride (SiNx), and a third layer containing silicon oxide (SiOx) or silicon oxynitride (SiOxNy).