Image Capture Device Light-Shielding Capacitor Structure

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Solution Overview

Problem

Laminate-type image capture devices face issues with false-signal generation due to light incidence on impurity regions, leading to noise and reduced image quality, as the photoelectric conversion layer is not effectively shielded from oblique light.

Innovation Solution

The image capture device incorporates a capacitor arrangement closer to the semiconductor substrate with electrodes functioning as light-shielding layers, reducing light incidence on impurity regions and incorporating a feedback circuit to cancel kTC noise, thereby enhancing image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the photoelectric conversion layer is arranged on an insulating layer above the semiconductor substrate, then the reading circuit can be formed on the semiconductor substrate, but light can incident on the impurity regions causing false-signal generation

Engineering Contradiction:

Improveformation of reading circuit on semiconductor substrateVSAvoidlight incidence on impurity regions causing false signals

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A light-shielding layer is introduced as an intermediary component between the photoelectric conversion layer and the impurity regions. This layer blocks oblique light from reaching the impurity regions while allowing the reading circuit to remain formed on the semiconductor substrate, thus resolving the contradiction between ease of manufacture and prevention of false signals.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The light-shielding layer is positioned in a different spatial dimension (between the photoelectric conversion layer and the impurity regions) to block light paths without interfering with the electrical connections and circuit formation on the substrate plane, thereby maintaining manufacturing ease while preventing light-induced false signals.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If the photoelectric conversion layer is positioned above the semiconductor substrate, then the device structure can be simplified, but oblique light can reach the impurity regions and generate noise

Engineering Contradiction:

Improvedevice structureVSAvoidimage quality affected by noise

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The light-shielding layer serves as a mediator that blocks oblique light paths to the impurity regions without adding significant structural complexity. It is integrated into the existing laminate structure, maintaining simplicity while improving reliability by preventing noise generation from light incidence.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If no light-shielding structure is provided, then the device structure remains simple, but false signals are generated due to light incidence on impurity regions

Engineering Contradiction:

Improvedevice structureVSAvoidimage quality

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The light-shielding layer is positioned between the photoelectric conversion layer and the impurity regions to block oblique light. This intermediary structure prevents false signal generation while maintaining relatively simple device architecture, thus resolving the contradiction between structural simplicity and image quality reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively suppresses false-signal generation and noise, improving image quality by shielding impurity regions from light and utilizing a feedback circuit to cancel noise, resulting in a more reliable image capture.

Implementation Method 1

charge generated by photoelectric conversion is accumulated in a charge accumulation region

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

a capacitor... includes a third electrode, a fourth electrode arranged between the third electrode and the semiconductor substrate, and a dielectric layer arranged between the third electrode and the fourth electrode

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10497739B2Image capture device including photoelectric converter supported by semiconductor substrate

Publication Date: 2019.12.03 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An image capture device includes pixels and a signal line that is arranged across two or more of the pixels. Each pixel includes: a semiconductor substrate, a photoelectric converter including a first electrode, a second electrode, and a photoelectric conversion layer; a first transistor including first and second impurity regions in the substrate; a wiring layer between the substrate and the second electrode; and a capacitor arranged between the wiring layer and the substrate in a normal direction of the substrate and including a third electrode, a fourth electrode between the third electrode and the substrate, and a dielectric layer. The first impurity region is electrically connected to the second electrode, the fourth electrode is electrically connected to one of the first and second impurity regions, and at least either the third or fourth electrodes covers the first impurity region when viewed along the normal direction.