Solid-State Image Sensor Voltage Control for Afterimage Reduction

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Solution Overview

Problem

Solid-state imaging devices with organic semiconductor materials outside the semiconductor substrate face challenges in enhancing afterimage characteristics due to kTC noise and signal charge overflow.

Innovation Solution

A solid-state imaging device with a configuration that includes a first and second electrode, a photoelectric conversion layer, and a voltage applier that applies different voltages to these electrodes during charge accumulation and non-accumulation periods, utilizing a barrier adjustment electrode to control potential differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If charges are accumulated in a floating diffusion layer formed inside the semiconductor substrate, then the device structure is simplified, but afterimage characteristics deteriorate due to kTC noise

Engineering Contradiction:

Improvedevice structureVSAvoidafterimage characteristics

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent transitions from horizontal charge accumulation in a floating diffusion layer to vertical charge accumulation in an organic photoelectric conversion layer disposed outside the semiconductor substrate. This dimensional change enables separation of the photoelectric conversion function from the charge accumulation function, allowing independent optimization of each and resolving the contradiction between structural simplicity and afterimage characteristics.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces an organic photoelectric conversion layer as an intermediary component between incident light and the semiconductor substrate. This layer serves as a mediator that converts light to charges outside the substrate, enabling charge accumulation without requiring internal floating diffusion structures, thus improving afterimage characteristics while maintaining structural efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a vertical transfer path with potential barrier layer is used, then afterimage characteristics are enhanced, but device complexity increases

Engineering Contradiction:

Improveafterimage characteristicsVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the organic photoelectric conversion layer: photoelectric conversion, charge generation, and charge accumulation. By merging these functions into a single external layer rather than using separate internal components like floating diffusion layers and potential barrier layers, the patent achieves good afterimage characteristics while avoiding increased device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the photoelectric conversion function from the semiconductor substrate and places it in an organic layer outside the substrate. This extraction eliminates the need for complex internal structures like floating diffusion layers and vertical transfer paths with potential barriers, achieving both good afterimage characteristics and structural simplicity.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If photoelectric conversion film is disposed outside semiconductor substrate, then new photoelectric materials can be used, but charge management becomes difficult due to kTC noise

Engineering Contradiction:

Improvephotoelectric material selectionVSAvoidcharge management

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies dynamic voltage control to the electrode adjacent to the organic photoelectric conversion layer, switching between a first voltage during photoelectric conversion and a second voltage during charge accumulation. This dynamic voltage adjustment actively manages charge transfer and accumulation, overcoming the charge management difficulties associated with external photoelectric conversion layers while maintaining material versatility.

Inventive Principle:

Principle #15Dynamics

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 afterimage characteristics by adjusting potential differences between electrodes, reducing kTC noise and improving charge management.

Implementation Method 1

kTC noise, which is one cause of the generation of an afterimage

Methodology Applied

Scientific EffectkTC noise:

Implementation Method 2

signal charges generated at a photoelectric transducer

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS12495222B2Solid-state imaging device and method of controlling solid-state imaging device

Publication Date: 2025.12.09 SONY SEMICON SOLUTIONS CORP

AI summary

Provided is a solid-state imaging device that includes a first electrode, a second electrode, a photoelectric conversion layer, and a voltage applier. The first electrode includes a plurality of electrodes independent from each other. The second electrode is disposed opposite to the first electrode. The photoelectric conversion layer is disposed between the first electrode and the second electrode. The voltage applier applies different voltages to at least one of the first electrode or the second electrode during a charge accumulation period and a charge non-accumulation period.