Stacked Imaging Sensor Insulator Layout for Reliable Charge Transfer

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Solution Overview

Problem

The existing imaging devices face challenges in reliably transferring electric charges stored in the photoelectric conversion layer to the first electrode during charge transfer, which affects the accuracy and efficiency of the imaging process.

Innovation Solution

The imaging device incorporates a configuration with a first electrode, a charge storage electrode, and a photoelectric conversion layer, where the insulating layer between them is divided into regions with different materials and polarities, optimizing the transfer of electric charges by varying the fixed charge density and polarity, ensuring reliable charge transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single uniform insulating layer is used between the charge storage electrode and photoelectric conversion layer, then the device structure is simple, but the charge transfer reliability is insufficient

Engineering Contradiction:

Improvecharge transfer reliabilityVSAvoidinsulating layer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The insulating layer is divided into multiple regions (first insulating layer and second insulating layer) with different fixed charge densities. The first insulating layer has a higher fixed charge density than the second insulating layer, creating distinct functional zones that improve charge transfer reliability while maintaining manageable structural complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the insulating layer are assigned different material compositions and fixed charge densities according to their specific functional requirements. The first insulating layer region closer to the charge storage electrode has higher fixed charge density for efficient charge extraction, while the second insulating layer region has lower fixed charge density for stable charge storage, optimizing local properties for each zone.

Inventive Principle:

Principle #3Local quality

2Productivity

If the fixed charge density is increased in the insulating layer to improve charge transfer, then charge transfer efficiency improves, but noise increases

Engineering Contradiction:

Improvecharge transfer efficiencyVSAvoidnoise

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The insulating layer is segmented into two regions with different fixed charge densities. The first insulating layer has higher fixed charge density to ensure efficient charge transfer, while the second insulating layer has lower fixed charge density to minimize noise generation, thus balancing transfer efficiency and noise control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fixed charge density parameter is varied across different regions of the insulating layer. By changing the fixed charge density from high in the first insulating layer to low in the second insulating layer, the system achieves both efficient charge transfer and reduced noise, resolving the contradiction between transfer efficiency and noise.

Inventive Principle:

Principle #35Parameter changes

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 enhances the reliability of electric charge transfer to the first electrode, improving the imaging process by reducing noise and maintaining high imaging quality.

Implementation Method 1

a photoelectric conversion layer that is formed in contact with the first electrode and is located above the charge storage electrode

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

the portion of the insulating layer that occupies the first region is formed with a first insulating layer, the portion of the insulating layer that occupies the second region is formed with a second insulating layer, and the absolute value of the fixed charge of the material forming the second insulating layer is smaller than the absolute value of the fixed charge of the material forming the first insulating layer

Methodology Applied

Scientific EffectFixed charge: Electrostatic Induction

Data Source

PatentUS11985838B2Imaging device, stacked imaging device, and solid-state imaging apparatus

Publication Date: 2024.05.14 SONY SEMICON SOLUTIONS CORP

AI summary

An imaging device includes: a first electrode; a charge storage electrode disposed at a distance from the first electrode; a photoelectric conversion layer in contact with the first electrode and above the charge storage electrode, with an insulating layer between the charge storage electrode and the photoelectric conversion layer; and a second electrode on the photoelectric conversion layer. The portion of the insulating layer between the charge storage electrode and the photoelectric conversion layer includes a first region and a second region, the first region is formed with a first insulating layer, the second region is formed with a second insulating layer, and the absolute value of the fixed charge of the material forming the second insulating layer is smaller than the absolute value of the fixed charge of the material forming the first insulating layer.