Electrochemical Semiconductor Separation via Hydroxyl Radical Ablation
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Solution Overview
Problem
The existing methods for separating semiconductor structures from growth substrates often result in mechanical stresses that degrade the optical and electronic properties of the semiconductor, particularly due to lattice mismatch and differences in thermal expansion coefficients, leading to structural defects like dislocations.
Innovation Solution
A method involving van der Waals epitaxy using a nucleation layer of at least three monolayers of two-dimensional material, where electrochemical ablation is employed to separate the semiconductor structure from the substrate by applying a potential difference between electrodes, generating hydroxyl radicals that react with the nucleation layer to degrade it and release the semiconductor structure without inducing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical stresses are applied to separate the semiconductor structure from the growth substrate, then separation is achieved, but the optical and electronic properties of the semiconductor structure are degraded
Solution Approach 1:
The patent replaces the mechanical separation method with an electrochemical method. Instead of applying mechanical stresses through a nickel stressing layer, the invention uses electrochemical etching with an electrolyte solution to remove the intermediate layer, thereby separating the semiconductor structure from the substrate without inducing mechanical stresses that would degrade optical and electronic properties.
Solution Approach 2:
The patent introduces an intermediate layer made of a specific material composition that serves as a sacrificial layer for electrochemical removal. This intermediate layer, positioned between the semiconductor structure and the growth substrate, enables controlled separation through electrochemical etching while protecting the semiconductor structure from damage during the separation process.
2Productivity
If electrochemical etching is used to separate the semiconductor structure, then the intermediate layer is removed effectively, but control over the etching process becomes challenging
Solution Approach 1:
The patent optimizes specific parameters of the electrochemical etching process, including the composition of the electrolyte solution (acidic or basic with specific pH ranges), temperature ranges (20-80°C), and voltage/current densities. These parameter optimizations enable effective removal of the intermediate layer while maintaining controllable and reproducible separation conditions.
Solution Approach 2:
The patent employs a standardized electrochemical etching process that can be replicated across different semiconductor structures and production batches. By establishing consistent electrolyte compositions, temperature ranges, and electrical parameters, the method achieves reproducible separation results that simplify process control and scaling for industrial production.
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 effectively preserves the optical and electronic properties of the semiconductor structure by avoiding mechanical stress, reducing structural defects, and enabling the production of high-quality semiconductor devices with improved internal quantum efficiency.
Implementation Method 1
application of a potential difference between said electrodes, adapted to cause the formation of hydroxyl radicals at the interface between the conductive surface and the aqueous electrolyte, which then react with the upper face and the lateral edge of the free surface of the nucleation layer, then degrading at least one intermediate monolayer of the nucleation layer
Implementation Method 2
formation of hydroxyl radicals at the interface between the conductive surface and the aqueous electrolyte
Implementation Method 3
epitaxy of the van der Waals type, from a growth substrate comprising a nucleation layer made of a two-dimensional material
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 1G~1I
AI summary
The invention relates to a method for manufacturing at least one semiconductor structure (20) separated from a support substrate (11), comprising the following steps: - creation of a two-dimensional nucleation layer (13) from the support substrate (11); - creation of the semiconductor structure (20) by epitaxy from the nucleation layer; - obtaining a first electrode (30) located in a lateral zone (3) which borders the semiconductor structure; - placement of the structure thus obtained in an aqueous electrolyte bath (50); - application of a potential difference between the electrodes (30, 40), until the separation of the semiconductor structure (20) from the support substrate (11) is caused.