Monocrystalline Silicon Dual-Scale Texture for Low-Damage Anti-Reflection
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Solution Overview
Problem
Existing laser texturing methods for monocrystalline silicon surfaces suffer from serious processing damage such as recast layers and hot cracks, and femtosecond laser processing is inefficient for material removal.
Innovation Solution
A combination of nanosecond-laser-assisted waterjet and femtosecond laser technologies is used to create a monocrystalline silicon micro-nano dual-scale anti-reflection texture, where nanosecond lasers prepare V-shaped grooves and femtosecond lasers induce sub-wavelength structures on these grooves to reduce damage and enhance light trapping and anti-reflection effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional nanosecond laser texturing is used, then material removal efficiency is improved, but serious processing damage such as recast layers and hot cracks occurs
Solution Approach 1:
The processing is divided into two distinct stages: first, nanosecond laser creates V-shaped grooves for material removal; second, femtosecond laser processes the grooves to eliminate damage. This segmentation allows each laser type to perform its optimal function without compromising the other.
Solution Approach 2:
The nanosecond laser performs preliminary action by creating V-shaped grooves that remove bulk material efficiently. This preliminary material removal reduces the workload for the subsequent femtosecond laser, enabling it to focus on eliminating processing damage with minimal additional material removal.
2Object-affected harmful factors
If femtosecond laser is used for texturing, then processing damage is reduced, but material removal efficiency becomes low
Solution Approach 1:
The nanosecond laser performs preliminary material removal to create V-shaped grooves, significantly reducing the amount of material that needs to be processed by the femtosecond laser. This enables the femtosecond laser to operate at low power settings focused on damage removal rather than bulk material removal.
Solution Approach 2:
The processing functions are segmented between two laser types: nanosecond laser handles bulk material removal, while femtosecond laser handles precision damage removal. This segmentation allows each component to operate in its optimal performance range.
3Object-affected harmful factors
If chemical etching method is used to remove processing damage, then recast layers can be removed, but technological process complexity and cost increase
Solution Approach 1:
The patent replaces chemical etching with a physical laser-based approach. The femtosecond laser directly removes recast layers and processing damage through ablation, eliminating the need for separate chemical etching steps and reducing process complexity.
Solution Approach 2:
The patent changes the processing parameter from chemical to physical by using ultrashort pulse laser ablation. This parameter change allows direct removal of recast layers through controlled vaporization rather than chemical dissolution, simplifying the overall process.
4Object-affected harmful factors
If chemical reagents are used for damage removal, then processing damage can be eliminated, but environment pollution is caused
Solution Approach 1:
The patent substitutes chemical reagents with a physical laser ablation process. The femtosecond laser removes processing damage through precise material vaporization, eliminating the need for harmful chemical reagents and their associated environmental pollution.
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 low processing damage, small recast layers, and reduced surface reflection by creating a hybrid structure with geometry light trapping and effective dielectric effects, while minimizing heat-affected zones.
Implementation Method 1
after being heated and softened by the nanosecond lasers in a to-be-processed area, a monocrystalline silicon material is sheared and removed by the waterjet in a plasticity mode
Implementation Method 2
Because of the ultrashort pulses, femtosecond laser can realize 'cold processing' of materials, so the heat affected zone is small
Implementation Method 3
a monocrystalline silicon material is sheared and removed by the waterjet in a plasticity mode
Implementation Method 4
incident light can be reflected several times in structure gaps so that a material can absorb most of incident light to form a light trapping effect
Implementation Method 5
an anti-reflection effect similar to a multi-layer gradient medium film is generated, namely an effective medium effect, and then reflection of the incident light can be restrained to a great degree
Data Source
AI summary
A monocrystalline silicon micro-nano dual-scale anti-reflection texture and a preparation method therefor. The preparation method combines nanosecond-laser-assisted waterjet near-damage-free processing and femtosecond laser scanning, and subsurface damage caused by a re-cast layer phenomenon and a hot crack in a monocrystalline silicon laser texturing process can be effectively reduced by combining a nanosecond-laser-assisted waterjet near-damage-free processing technology and an ultra-short pulse femtosecond laser cold processing technology; and meanwhile, a micro-scale frame structure and a nano-scale structure can be flexibly modified respectively by adjusting nanosecond-laser-assisted waterjet technological parameters and femtosecond laser technological parameters, a geometry light trapping effect and an effective dielectric effect can be achieved in a micro-nano dual-scale hybrid structure at the same time, and surface reflection is reduced.