Plasmonic Infrared Detector Structure for Fast SWIR Absorption
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Solution Overview
Problem
Existing photodetectors face challenges in achieving high-speed operation, increasing light absorption rates, and enhancing integration degree while minimizing dark current and parasitic impedance.
Innovation Solution
The proposed solution involves an infrared detector with a substrate, an infrared absorption layer containing a metal nanostructure aligned to match the mode period of incident light, and electrode layers spaced apart to increase light absorption and trapping time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the size of the light detection layer is reduced to improve high-speed operation characteristics, then operation speed is improved, but light absorption rate decreases
Solution Approach 1:
The patent uses a composite structure combining semiconductor material (e.g., InGaAs) with metal nanopatterns (e.g., gold nanoparticles) in the light detection layer. This composite approach enables the layer to maintain thin dimensions for high-speed operation while the metal nanoparticles provide enhanced light absorption through plasmonic effects, thus resolving the contradiction between speed and absorption rate
Solution Approach 2:
The patent modifies the optical parameters of the light detection layer by introducing metal nanopatterns with specific sizes, shapes, and arrangements. These parameter changes enable resonant enhancement of light absorption at specific wavelengths, allowing the thin detection layer to achieve high absorption rates without compromising operation speed
2Object-generated harmful factors
If the size of the light detection layer is reduced to decrease dark current, then dark current is reduced, but light absorption rate decreases
Solution Approach 1:
The composite structure of semiconductor material with embedded metal nanopatterns allows the detection layer to be made thinner, which inherently reduces dark current. Simultaneously, the metal nanoparticles compensate for the reduced absorption area by providing plasmonic enhancement, thus achieving both low dark current and high light absorption rate
3Device complexity
If electrode layers are placed closer to increase integration degree, then integration density is improved, but parasitic impedance increases
Solution Approach 1:
The patent transitions from planar electrode arrangement to a three-dimensional configuration where electrodes are positioned at different vertical levels (e.g., top and bottom surfaces of the detection layer). This dimensional change allows compact integration while maintaining sufficient electrical distance to minimize parasitic impedance between electrodes
4Speed
If the light detection layer is made thinner to improve operation speed, then operation speed is improved, but light absorption rate decreases
Solution Approach 1:
The patent changes the optical parameters of the thin detection layer by incorporating metal nanopatterns with specific resonant properties. These nanoparticles are designed to resonate at the operating wavelength, creating localized surface plasmon resonances that dramatically enhance the optical field and absorption efficiency within the thin layer, thus maintaining high absorption rates despite reduced thickness
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 configuration enables high-speed operation, increased light absorption rates, and enhanced integration degree, while reducing dark current and parasitic impedance, thus improving the performance of photodetectors in optical interconnection structures.
Implementation Method 1
a metal nanostructure embedded in a center of the infrared absorption layer and positioned to correspond to a mode period of incident light
Data Source
AI summary
An infrared detector, a manufacturing method thereof, and an optical interconnection structure including an infrared detector are provided. The infrared detector according to an embodiment includes an infrared absorption layer that is in contact with a substrate and is provided to absorb short-wavelength infrared rays and first and second electrode layers connected to the infrared absorption layer and spaced apart from each other. The infrared absorption layer includes a metal nanostructure embedded in the center of the infrared absorption layer and positioned to correspond to a mode period of incident light. A light reflection layer may be further provided at an end portion of the infrared absorption layer.