Polycycloolefinic Dielectric for OFETs

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Solution Overview

Problem

Conventional organic field effect transistors (OFETs) face challenges with dielectric layers that lack cross-linking functionality, leading to increased permittivity and reduced performance due to the generation of polar or charged by-products during cross-linking, and require the use of fluorinated solvents, which are environmentally and cost-inefficient.

Innovation Solution

A polycycloolefinic polymer with pendant olefinic groups is used in the dielectric layer, allowing for controlled isomerization and providing solubility, cross-linking functionality, and low permittivity, enabling photo-patterning and stack integration without generating undesired by-products, and can be deposited from non-halogenated solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluorodielectrics like Cytop or Hyflon polymers are deposited from fluorosolvents to provide low permittivity and good orthogonality, then the dielectric layer achieves low k value and compatibility with OSC materials, but the use of fluorinated solvents causes environmental and cost issues

Engineering Contradiction:

Improvedielectric performanceVSAvoidenvironmental impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the solvent parameter from fluorinated to non-fluorinated (hydrocarbon-based) while maintaining the dielectric performance by using polycycloolefinic polymers with specific chemical structures that achieve low k values without requiring fluorinated solvents

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive and environmentally problematic fluorinated solvents with cheaper, more environmentally friendly hydrocarbon-based solvents, reducing both cost and environmental impact while achieving the same functional results

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Adaptability or versatility

If cross-linking functionality is incorporated into the dielectric to enable photo-patterning, then via interconnect formation is enabled, but polar or charged by-products are generated as side products

Engineering Contradiction:

Improvephoto-patterning capabilityVSAvoidpolar by-products

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potential harm of by-product generation into a benefit by selecting cross-linking reactions that produce non-polar, neutral by-products (such as water or neutral molecules) that do not interfere with the OSC layer, thus enabling photo-patterning without compromising device performance

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent uses specific cross-linking agents and reaction mechanisms that act as intermediaries to achieve cross-linking while minimizing harmful by-products, selecting reactions that proceed through pathways that avoid generating polar or charged species

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If cross-linking is performed to enable photo-patterning, then stack integration is improved, but the k value increases due to incorporated by-products

Engineering Contradiction:

Improvestack integrationVSAvoidpermittivity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent converts the potential harm of k-value increase into a benefit by selecting cross-linking reactions that produce neutral, non-polar by-products that do not increase the dielectric constant, thus enabling stack integration while maintaining low k values

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of manufacture

If conventional dielectrics are used without cross-linking functionality, then the dielectric layer is simple to deposit, but via interconnect patterning cannot be achieved

Engineering Contradiction:

Improvedeposition simplicityVSAvoidvia interconnect formation

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent merges the simplicity of conventional dielectric deposition with the functionality of cross-linking by using polycycloolefinic polymers that can be deposited from solution and then cross-linked in situ, combining the ease of manufacture with photo-patterning capability in a single integrated process

Inventive Principle:

Principle #5Merging (Combining)

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 results in high mobility and low off-currents in OFETs, maintaining low permittivity and orthogonality to organic semiconductor materials, while allowing for efficient photo-patterning and stack integration, improving the overall performance and environmental sustainability of the devices.

Implementation Method 1

wherein preferably the isomerization of the C—C double bond in the olefinic chain can be controlled

Methodology Applied

Scientific EffectIsomerization:

Implementation Method 2

can be cross-linked to enable photo-patterning

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS9978944B2Organic electronic compositions and device thereof

Publication Date: 2018.05.22 FLEXENABLE TECH LTD

AI summary

The present invention relates to organic electronic devices, and more specifically to organic field effect transistors, comprising a dielectric layer that comprises a polycycloolefinic polymer with an olefinic side chain.