Image Sensor Photoelectric Conversion Layer Integration
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Solution Overview
Problem
Current image sensors face challenges in optimizing the integration of photoelectric conversion layers and color filters to enhance light detection efficiency and pixel integration, particularly in CMOS image sensors.
Innovation Solution
The proposed image sensor design includes an active region, a peripheral region, and a dummy region with specific electrode and insulation structures, where a photoelectric conversion layer is interposed between top and active bottom electrodes, and color filters are embedded in the insulation structure to separate and manage light signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a photoelectric conversion layer is shared between active and dummy regions, then device complexity is reduced and manufacturing is simplified, but light detection precision may be compromised without proper isolation structures
Solution Approach 1:
The patent segments the photoelectric conversion layer into distinct active and dummy regions using isolation structures. The dummy region is further divided into sub-regions (first dummy region with first photoelectric conversion layer, second dummy region with second photoelectric conversion layer) that are electrically isolated from each other and from the active region, allowing independent control and measurement functions.
Solution Approach 2:
The patent introduces intermediary components including isolation trenches filled with insulating material, isolation dielectric layers, and transfer gates that act as mediators between the shared photoelectric conversion layer and the respective readout circuits. These intermediaries enable precise control and measurement while maintaining the shared structure.
2Measurement precision
If color filters are embedded in the insulation structure, then light signal management and wavelength separation are improved, but manufacturing precision requirements increase
Solution Approach 1:
The color filters are formed in advance within the insulation structure before the photoelectric conversion layer is deposited. This preliminary formation of color filters in the insulation structure (first and second color filters in first and second color filter regions) establishes the wavelength separation framework before the shared photoelectric conversion layer is created, simplifying subsequent manufacturing steps.
Solution Approach 2:
The insulation structure serves multiple functions: it provides electrical isolation between doped regions, supports embedded color filters for wavelength separation, and acts as a structural foundation for the photoelectric conversion layer. This multi-functionality reduces the need for separate components and simplifies the overall device architecture.
3Productivity
If dummy regions are introduced between active and peripheral regions, then pixel integration and light detection efficiency are improved, but device area increases
Solution Approach 1:
The patent merges the dummy region functionality with the active region by using a shared photoelectric conversion layer. The dummy regions (first and second dummy regions) are integrated alongside active regions in the same semiconductor substrate, sharing common structures such as the photoelectric conversion layer, insulation structure, and electrode connections, thereby improving integration efficiency without proportionally increasing area.
Solution Approach 2:
The patent utilizes vertical dimensionality by forming doped regions (first and second doped regions) at different depths within the semiconductor substrate. The photoelectric conversion layer is positioned in the vertical space above these doped regions, allowing efficient use of the substrate volume and reducing the horizontal footprint of the sensor.
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 design improves light detection efficiency and pixel integration by allowing shared photoelectric conversion layers and color filters to manage different wavelengths of light, increasing the overall performance of the image sensor.
Implementation Method 1
A photoelectric conversion layer is disposed on the insulation structure of the active region. A top electrode is disposed on the photoelectric conversion layer... The photoelectric conversion layer is interposed between the top electrode and the active bottom electrode
Implementation Method 2
A color filter is embedded in the insulation structure... increasing the overall performance of the image sensor
Data Source
AI summary
An image sensor having active, peripheral and dummy regions is provided as follows. A dummy through electrode is disposed in the substrate. An active through electrode is disposed in the substrate. An insulation structure in which a color filter is embedded is disposed on the substrate. A dummy bottom electrode is disposed on the insulation structure and connected electrically to the dummy through electrode. An active bottom electrode is disposed on the insulation structure and connected electrically to the active through electrode. A photoelectric conversion layer is disposed on the insulation structure. A top electrode is disposed on the photoelectric conversion layer and the dummy bottom electrode. The top electrode is connected electrically to the dummy bottom electrode. The photoelectric conversion layer is interposed between the top electrode and the active bottom electrode which are separated from each other.