Organic Image Sensor Protection Layers for Plasma Damage

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Solution Overview

Problem

Conventional organic CMOS image sensors face performance degradation due to plasma damage from plasma vapor deposition processes used in forming electron- or hole-blocking layers, which can damage the exposed surface of the organic photoelectrical conversion structure, and are also susceptible to degradation from oxygen and moisture.

Innovation Solution

Incorporating protection layers formed through atomic layer deposition (ALD) to shield the organic photoelectrical conversion structure from plasma damage and enhance electron- or hole-blocking capabilities, while using transparent electrodes and charge-blocking layers to manage charge movement and prevent leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plasma vapor deposition is used to form electron- or hole-blocking layers, then the blocking capability is improved, but plasma damage occurs to the organic photoelectrical conversion structure

Engineering Contradiction:

Improveblocking capabilityVSAvoidplasma damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An aluminum oxide protection layer is introduced as an intermediary between the organic photoelectrical conversion structure and the plasma vapor deposition process. This protection layer acts as a barrier that prevents direct plasma contact with the organic structure, thereby eliminating plasma damage while allowing the blocking layers to be formed with high capability on top of the protection layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The aluminum oxide protection layer is formed beforehand using atomic layer deposition (ALD) to create a protective barrier before the plasma vapor deposition process begins. This pre-formed protection layer cushions the organic photoelectrical conversion structure against subsequent plasma exposure, preventing damage before it can occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of manufacture

If the organic photoelectrical conversion structure is exposed to oxygen and moisture, then manufacturing is simplified, but degradation occurs

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidstability against degradation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A thin film aluminum oxide protection layer is deposited over the organic photoelectrical conversion structure to create a protective shell that seals the organic material from environmental exposure. This thin film approach maintains manufacturing simplicity while providing effective barrier protection against oxygen and moisture-induced degradation.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The aluminum oxide protection layer creates an inert environment around the organic photoelectrical conversion structure, effectively isolating it from reactive oxygen and moisture in the external environment. This inert barrier prevents chemical degradation while allowing the device to be manufactured and operated in standard atmospheric conditions.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 protection layers improve the reliability and efficiency of the organic image sensor by preventing plasma damage and enhancing blocking capabilities, leading to better performance and reduced noise in digital images.

Implementation Method 1

Incorporating protection layers formed through atomic layer deposition (ALD) to shield the organic photoelectrical conversion structure from plasma damage

Methodology Applied

Scientific EffectPhysical barrier protection:

Implementation Method 2

are also susceptible to degradation from oxygen and moisture

Methodology Applied

Scientific EffectBarrier protection against environmental degradation:

Implementation Method 3

a first charge blocking structure disposed between the first electrode and the organic photoelectrical conversion structure to restrain a first kind of electric charge to move from the first electrode to the organic photoelectrical conversion structure

Methodology Applied

Scientific EffectCharge blocking:

Implementation Method 4

The organic photoelectrical conversion structure is configured to convert one or more photons having wavelength falling within a predetermined wavelength range into an electrical signal

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS20150380669A1Protective layer(s) in organic image sensors

Publication Date: 2015.12.31 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

The present disclosure relates to an organic image sensor and an associated method. By inserting an inorganic protective layer between an electrode and an organic photo active region of the image sensor, the organic photo active region is protected from moisture, oxygen or following process damage. The inorganic protective layers also help to suppress the leakage in the dark. In some embodiments, the organic image sensor comprises a first electrode, an organic photoelectrical conversion structure disposed over the first electrode and a second electrode disposed over the organic photoelectrical conversion structure. The organic image sensor further comprises a first protective structure covering a top surface and a sidewall of the organic photoelectrical conversion structure.