Solar Cell Texturing via Dry Etching to Reduce Surface Damage
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Solution Overview
Problem
The texturing process for solar cells often damages the wafer surface, leading to defects that reduce the conversion efficiency by causing carrier recombination and decreasing the current output.
Innovation Solution
A method involving dry etching to create jagged portions on the wafer surface with inclinations greater than 54.76° and less than 90°, followed by wet etching to minimize surface damage, and the application of anti-reflective layers to enhance light scattering and reduce reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a texturing process is performed on the wafer surface to reduce reflected light and increase light scattering, then the conversion efficiency of the solar cell is improved, but the wafer surface is damaged causing defects that reduce current output
Solution Approach 1:
The patent replaces the conventional wet chemical texturing process with a plasma-based dry texturing process. The plasma treatment creates the desired surface roughness and light scattering properties without the mechanical and chemical damage caused by traditional wet etching methods, thus maintaining wafer surface quality while achieving the goal of reducing reflected light
Solution Approach 2:
The patent modifies the texturing process parameters by using controlled plasma exposure conditions (power, gas flow, treatment time) to achieve the desired surface morphology. By optimizing these parameters, the process creates effective light scattering surfaces while minimizing surface damage and defects that would otherwise reduce current output
2Productivity
If the texturing process is performed to increase the scattering surface of light, then the conversion efficiency is improved, but surface damage occurs leading to carrier recombination
Solution Approach 1:
The patent substitutes wet chemical etching with plasma processing to create surface texturing. This replacement eliminates the harmful chemical reactions and mechanical stress that cause surface damage and carrier recombination, while still achieving the necessary light scattering effect to improve conversion efficiency
Solution Approach 2:
The patent introduces plasma as an intermediary medium to achieve surface texturing. The plasma acts as a controlled energy source that can be precisely regulated to create the desired surface morphology without directly contacting or chemically damaging the wafer, thereby preventing carrier recombination sites while maintaining high conversion efficiency
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 increases the conversion efficiency of solar cells by reducing surface damage and enhancing light absorption, resulting in improved short-circuit current, open-circuit voltage, and fill factor.
Implementation Method 1
texturing a surface of a substrate of the solar cell using dry etching
Implementation Method 2
wet etching the surface of the substrate to reduce a damage to the surface caused by the texturing
Implementation Method 3
forming at least one anti-reflective layer on the textured surface of the substrate
Implementation Method 4
enhancing light scattering and reduce reflectance
Implementation Method 5
A solar cell converts energy of incident light into electrical energy through a photovoltaic effect
Data Source
AI summary
A method of manufacturing a solar cell includes forming jagged portions non-uniformly on a surface of a substrate, forming a first type semiconductor and a second type semiconductor in the substrate, forming a first electrode to contact the first type semiconductor, and forming a second electrode to contact the second type semiconductor. An etchant used in a wet etching process in manufacturing the solar cell includes about 0.5 wt % to 10 wt % of HF, about 30 wt % to 60 wt % of HNO3, and up to about 30 wt % of acetic acid based on total weight of the etchant.