CMOS Image Sensor Metal Pattern Layer Surface Plasmon Resonance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional CMOS image sensors suffer from reduced sensitivity due to the size reduction of photodiodes and light absorption by color filters, as well as signal distortion from light cross-talk caused by metal wiring, leading to inefficient light detection and image processing.
Innovation Solution
A CMOS image sensor incorporating a p-n junction photodiode with a metal pattern layer that utilizes surface plasmon resonance, eliminating the need for a separate color filter and reducing light absorption, while the metal pattern acts as a wavelength-specific filter, enhancing light detection and reducing cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional color filter is used to filter light wavelengths, then light filtering is achieved, but light absorption increases and sensitivity decreases
Solution Approach 1:
The patent changes the physical and chemical parameters of the metal pattern layer by controlling particle size (50-200 nm), material composition (Au, Ag, Cu, Al, W), and layer thickness (3-100 nm) to achieve wavelength-specific filtering through surface plasmon resonance, replacing conventional color filters and improving light transmission to the photodiode
Solution Approach 2:
The patent uses composite structures combining metal nanoparticles with dielectric films (SiO2, SiON, HfO2, Si3N4) to create a metal pattern layer that provides both filtering and structural functions, eliminating the need for separate color filter layers while maintaining or improving sensitivity
2Volume of moving object
If the photodiode size is reduced to compensate for vertical distance, then the sensor can be more compact, but sensitivity is reduced
Solution Approach 1:
The patent changes the optical interaction parameters by introducing surface plasmon resonance through metal patterns, which enhances light-matter interaction efficiency and allows for improved sensitivity even with reduced photodiode dimensions, breaking the traditional scaling limitation
3Ease of manufacture
If metal wiring is used for peripheral circuits, then electrical connectivity is achieved, but light reflection causes optical cross-talk and signal distortion
Solution Approach 1:
The patent applies local quality by making the metal pattern layer wavelength-selective through surface plasmon resonance, allowing it to transmit specific wavelengths (red, green, blue sub-pixel regions) while blocking others, thereby enabling color filtering at the pixel level and reducing optical cross-talk between adjacent pixels
Solution Approach 2:
The patent converts the harmful light reflection from metal wiring into a beneficial wavelength-selective filtering mechanism by using surface plasmon resonance in the metal pattern layer, which actively manages light transmission and reduces optical cross-talk rather than merely reflecting light
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 solution increases the sensitivity of the image sensor by allowing more light to reach the photodiode, reduces signal distortion, and enables a more compact design without a separate color filter, thereby improving light detection efficiency and image quality.
Implementation Method 1
a metal pattern layer that utilizes surface plasmon resonance
Implementation Method 2
The photodiode and the transistors may be integrated on a single chip. The p-n junction photodiode may generate charges by detecting external light
Data Source
AI summary
Provided are photodiodes, image sensing devices and image sensors. An image sensing device includes a p-n junction photodiode having a metal pattern layer on an upper surface thereof. An image sensor includes the image sensing device and a micro-lens formed above the metal pattern layer. The metal pattern layer filters light having a first wavelength.