SERS Substrate with Reflective Optical System for Hot Spot Density
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Solution Overview
Problem
Existing methods for manufacturing substrates for surface-enhanced Raman scattering (SERS) are complex, expensive, and limited in producing substrates with high densities of 'hot spots,' resulting in insufficient enhancement of the Raman signal intensity.
Innovation Solution
A method involving the deposition of a multilayer with selectively etchable interlayers, forming trenches and cavities to create metal pins, and integrating a reflective optical system that directs incident light into these cavities, enhancing the electromagnetic field and Raman signal intensity without producing SERS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high spatial resolution structuring technologies are used to form hot spots, then the precision of hot spot formation is improved, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The invention segments the substrate manufacturing into distinct functional layers (metal layers, dielectric layers, reflective layer) that can be processed independently through sequential deposition and etching steps. This allows hot spots to be formed through simple planar patterning rather than requiring complex 3D structuring technologies, thereby reducing device complexity while maintaining manufacturing precision.
Solution Approach 2:
The invention transitions from forming hot spots through complex lateral 3D structuring (spikes, cavities requiring high-resolution lithography) to a simplified planar approach where hot spots are created through the interaction of light with patterned reflective layers and metal structures in the same plane. This dimensional simplification reduces the required structuring technology complexity while maintaining hot spot formation precision.
2Quantity of substance
If conventional hot spot formation methods are used, then the manufacturing process is established, but the hot spot density remains limited and Raman signal enhancement is insufficient
Solution Approach 1:
The invention performs preliminary actions by pre-forming trenches and depositing reflective layers in specific patterns before final metal layer deposition. This preliminary structuring enables the subsequent formation of high-density hot spots through simpler processes, increasing both hot spot density and Raman signal enhancement efficiency without requiring complex manufacturing steps.
Solution Approach 2:
The invention uses composite material structures combining metal layers, dielectric layers, and reflective layers in a multilayer architecture. This composite structure enables the formation of high-density hot spots through the interaction between different material layers, significantly increasing hot spot density and Raman signal enhancement compared to single-material structures.
3Ease of manufacture
If simple manufacturing methods are used, then the ease of manufacture is improved, but the substrate cannot achieve high hot spot density for sufficient signal enhancement
Solution Approach 1:
The invention segments the manufacturing process into simple, sequential steps (depositing multilayer, etching trenches, depositing reflective layer, etching cavities) that can be performed using standard semiconductor fabrication equipment. This segmentation maintains ease of manufacture while enabling high hot spot density through the cumulative effect of each simple step.
Solution Approach 2:
The invention achieves high hot spot density by transitioning from complex lateral structuring to a planar multilayer approach where density is controlled by the pattern density of the reflective layer and metal structures. This allows simple manufacturing processes to produce high-density hot spots by optimizing the areal density of patterned features rather than relying on complex 3D geometries.
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 method allows for the simple, reproducible, and cost-effective production of substrates with a high density of hot spots, significantly increasing the Raman signal intensity, enabling faster detection of molecules at low concentrations.
Implementation Method 1
a reflective optical system in each trench, the reflective optical system being arranged to direct inside the cavities incident light arriving at an angle α with respect to the upper surface of the support
Implementation Method 2
the roughness of the metal surface of the substrate which carries the molecules of interest makes it possible to enhance the Raman signal emitted by the molecules of interest thanks to the excitation of localized plasmons of the metal (enhancement by electromagnetic effect)
Data Source
Figure 1a~1c
Figure 1d~1e
Figure 1f~2b
AI summary
The invention relates to a substrate (18) for surface-enhanced Raman scattering comprising: - a support (1) having an upper surface (3); - a multilayer (2) deposited on the upper surface (3) of the support (1), the multilayer (2) comprising at least two metallic layers (4) separated from each other by an interlayer (5), the interlayer (5) being able to be selectively etched with respect to the metallic layers (4), the multilayer (2) being traversed by at least one trench (6) delimited by ends (7, 8) of each of the layers (4, 5) of the multilayer (2), each end (8) of each interlayer (5) being recessed with respect to the end (7) of each metallic layer (4) adjacent to this interlayer (5) so that the ends (7) of two successive metallic layers (4) form metallic studs (7) separated by a cavity (11);- a reflective optical system (12) arranged in each trench (6), the reflective optical system (12) being arranged to direct into the cavities (11) an incident light (13) arriving at an angle α with respect to the upper surface (3) of the support (1).;