N-Type Silicon Back Layer for Solar Cells Without Film Explosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solar cell panel production methods experience film explosion issues due to hydrogen escape during high-temperature annealing, leading to reduced passivation effect and open-circuit voltage, especially on polished or textured cell pieces.
Innovation Solution
A process involving the formation of multiple N-type silicon layers with varying phosphine concentrations on a silicon oxide layer, where the phosphine concentration increases with thickness, effectively binding hydrogen atoms and preventing film explosion, thereby enhancing passivation and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of hydrogen is introduced during PECVD to enhance passivation effect, then the passivation effect is improved, but film explosion occurs during high-temperature annealing due to hydrogen escape
Solution Approach 1:
The patent changes the chemical composition parameter of the silicon layer by introducing phosphine (PH3) during PECVD deposition. This creates a phosphorus-doped silicon layer that binds hydrogen atoms, preventing the film explosion that occurs when pure hydrogen-rich layers are subjected to high-temperature annealing. The phosphine concentration is controlled within 0.1-10% to achieve optimal hydrogen binding without compromising passivation quality.
Solution Approach 2:
Phosphorus atoms introduced via phosphine serve as an intermediary substance that binds hydrogen atoms in the silicon layer. This intermediary mechanism prevents direct hydrogen escape during annealing, thereby avoiding film explosion while maintaining the passivation benefits of hydrogen in the silicon oxide interface.
2Reliability
If phosphine concentration is increased to bind hydrogen and prevent film explosion, then film explosion is prevented, but manufacturing complexity increases due to multi-layer deposition
Solution Approach 1:
The silicon layer is segmented into multiple sub-layers with different phosphine concentrations. The first silicon layer has lower phosphine concentration (0.1-5%) for initial hydrogen binding, while the second silicon layer has higher phosphine concentration (0.5-10%) for enhanced hydrogen binding and film stability. This segmentation allows optimization of hydrogen binding at different depths while maintaining process control.
Solution Approach 2:
Different regions of the silicon layer structure have different phosphine concentrations tailored to local requirements. The lower phosphine concentration near the silicon oxide interface provides sufficient hydrogen binding for passivation, while the higher phosphine concentration in the upper layer provides additional hydrogen binding capacity and film stability, creating a gradient structure that optimizes both passivation and explosion prevention.
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 solution significantly increases open-circuit voltage, conversion efficiency, and filling factor while preventing film explosion, improving the overall quality of the solar cell panel.
Implementation Method 1
a phosphine concentration of the N-type silicon layer is within a first preset concentration range... so as to bind hydrogen atom during a high-temperature annealing process
Implementation Method 2
forming a silicon oxide layer on a backside of an N-type silicon wafer
Implementation Method 3
forming an anti-reflection layer on the N-type silicon layer
Data Source
AI summary
A silicon oxide layer is formed on the back surface of an N-type silicon wafer; an N-type silicon layer is formed on the silicon oxide layer, wherein the phosphine concentration of the N-type silicon layer is within a first preset concentration range; and an antireflection layer is formed on the N-type silicon layer and a back electrode is formed on the antireflection layer. In the high-temperature annealing process, hydrogen atoms can be bound by phosphine, such that membrane explosion caused by the escape of hydrogen atoms is avoided, an open-circuit voltage, the conversion efficiency and a filling factor can be improved, a back passivation effect can be enhanced, and the quality of a cell piece can be improved.