Plasmonic Nanostructure Sensor Pixel IR Sensitivity
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Solution Overview
Problem
The silicon substrate in existing IR-sensitive pixels absorbs infrared light less efficiently compared to visible light, limiting the sensitivity of the pixel array to IR light.
Innovation Solution
A plasmonic-nanostructure sensor pixel is introduced, featuring a semiconductor substrate with metal pillars or nanoparticles that enhance the absorption of IR light by coupling it into surface plasmons, improving quantum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon substrate is used for IR detection, then the pixel can detect infrared light, but the absorption efficiency of IR light is much lower than visible light
Solution Approach 1:
The patent changes the physical parameters of the silicon substrate by introducing metal nanoparticle arrays with specific sizes (50-200 nm diameter) and spacing (100-300 nm). These structural parameter changes create localized surface plasmon resonances that enhance IR light absorption at specific wavelengths, directly addressing the low absorption efficiency problem while maintaining IR detection capability
Solution Approach 2:
The patent creates a composite structure by combining metal nanoparticles (gold, silver, aluminum, or copper) with the silicon substrate. This composite material system leverages the plasmonic properties of metals to enhance the optical absorption characteristics of silicon in the IR range, resolving the contradiction between maintaining detection capability and improving absorption efficiency
2Reliability
If the pixel array is designed for visible light detection, then visible light sensitivity is high, but IR light sensitivity is limited
Solution Approach 1:
The patent segments the pixel structure by introducing discrete metal nanoparticle arrays on the silicon substrate surface. These nanoparticles are arranged in specific patterns (periodic or aperiodic) with controlled densities, creating localized plasmonic hotspots that enhance IR absorption without fundamentally redesigning the entire pixel architecture, thus managing device complexity
Solution Approach 2:
The patent applies local quality enhancement by placing metal nanoparticles at specific locations on the silicon substrate where they create localized surface plasmon resonances. This localized approach enhances IR absorption at specific regions without requiring uniform modification across the entire pixel array, balancing performance improvement with structural simplicity
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 plasmonic-nanostructure sensor pixel significantly enhances the quantum efficiency for IR light, particularly at wavelengths longer than 740 nm, by increasing the absorption of IR light, thereby improving the sensitivity of the pixel array to IR radiation.
Implementation Method 1
enhance the absorption of IR light by coupling it into surface plasmons
Data Source
AI summary
A first plasmonic-nanostructure sensor pixel includes a semiconductor substrate and a plurality of metal pillars. The semiconductor substrate has a top surface and a photodiode region therebeneath. The plurality of metal pillars is at least partially embedded in the substrate and extends from the top surface in a direction substantially perpendicular to the top surface. A second plasmonic-nanostructure sensor pixel includes (a) a semiconductor substrate having a top surface, (b) an oxide layer on the top surface, (c) a thin-film coating between the top surface and the oxide layer, and (d) a plurality of metal nanoparticles (i) at least partially between the top surface and the oxide layer and (ii) at least partially embedded in at least one of the thin-film coating and the oxide layer. A third plasmonic-nanostructure sensor pixel includes features of both the first and second plasmonic-nanostructure sensor pixels.